These instructions are the work of Mike 94PGT and have been re-designed to fit with the site and hosted here as a service to the Probe and MX6 community.

What's In Here ?

This page outlines the basic procedure for retrieving malfunction codes from the PCME (Powertrain Control Module - Engine) on your 1993 through 1995 Ford Probe GT. Other Mazda MECS-II (Mazda Engine Control System - II) equipped vehicles like the 1.8L V6 Mazda MX3 can also use the general procedure outlined below though some of the code descriptions may not be exactly applicable to the vehicle. If possible, always consult a service manual before attempting to pull codes from your car and by all means, DO NOT simply start shorting wires together at random to get codes to flash as damage may occur to the car.

I cannot be held responsible for any damage resulting to any vehicle from using the directions given on this page. This stuff works as is on my car, a 1994 Probe GT and should be okay on yours. Don't take my word for it.

GT Special Exceptions:

Not all Probes are created equal. This page applies, in general, to 1993 through 1995 Probe GTs (or "24V" models as they are known in Europe, Australia and elsewhere.) In 1996, Ford equipped the PGT with OBD-II which is a much different engine control system than the OBD-I system used on the 93-95 models. OBD-II regulations state that malfunction codes cannot be extracted by simply shorting a pin somewhere and watching the Check Engine Lamp (CEL). Instead, the system requires you to either purchase a scan tool to read the serial data and malfunction codes or to take the car to a dealership and have them do it.

Got a 4-cylinder (Base or SE) 2nd-gen Ford Probe ?

1993 to 1995 Ford Probes in the SE and base trim levels use Ford's very own EEC-IV system which is much, much different than the MECS-II system used on the 2nd-gen GT. Do NOT use the information on this page to get codes from these cars. Instead, go to this excellent site here to see how to read and interpret the codes from the EEC-IV system and perform other system tests.

Reading the Codes for the 1993-1995 GT

• Locate and open the "Diagnostic" box under the hood. It's between the battery and the fender. Below is shown a representation of the pins inside the Diagnostic box
• The pins labelled "TEN" (which stands for "Test ENgine" by the way) and GND (ground) are the pins of interest.
• Make sure the ignition is OFF and use a paperclip to jumper the TEN and GND pins together.
• Turn on the ignition (do not start the car)
• Watch the CEL. After about 4-seconds, it will begin to flash any codes that may be stored.
• If there are no codes stored, the CEL will not flash (it will go out.)

Malfunction codes are generally 2-digit affairs although Mazda decided to get tricky. They include 2-digit codes that involve '0' (zero) as a digit. Code 02 is one example. Code 10 is another.

The codes are broken into a 10's digit and a 1's digit. The 10's digit is flashed first, followed by the 1's digit. The digits are distinguished by the length of time they flash the CEL. 10's digits flash the CEL on for 1.2-sec while 1's digits flash the CEL for 0.4-sec. Digits that are '0' (zero) flash the CEL exactly zero times.

The diagram below illustrates graphically how two typical malfunction codes might be flashed out

Note how the presumably single-digit code '3' flashes the CEL for short-pulses only. This indicates the 10s digit is zero for this code.

The image below illustrates what the CEL would do if, say, a code 24 were the only code present. Note that it's "dark" (off) for 4-seconds, then the code flashes (long flashes are 10s digits, short flashes are 1s digits). Since this is the only code, there is a 4-second pause between flashing sequences.

If you find yourself saying "Uh-oh"...

Notice in the above drawing that the TEN pin is located right next to the B+ pin... If you screw up and connect the B+ pin to the GND pin, you'll cause a short circuit when the ignition is switched on. You'll probably notice that the instrument cluster gauges don't work any more, along with other systems of the car. If you've done this, check the METER fuse in the fuse panel inside the car. Once you've replaced it, your gauges should operate as normal.

The Diagnostic Connector

The diagnostic connector is located under the hood near the battery. The following lists the populated pins on North American vehicles. My documentation does not list several of the pins since these features weren't included in North American cars.

Pin	Pin Name	Function
A	FEN	Trouble code output (engine control computer)
B	MEN	Switch monitor output (engine control computer)
C	TEN	Diagnostic-mode input (engine control computer)
D	+B	Switched battery voltage
E	GND	Ground
F	FAT	Trouble code output (automatic transmission control computer)
G	FBS	Trouble code output (anti-lock brakes (ABS) control computer)
H	FAC	Trouble code output (? not documented for North American vehicles)
J	FWS	Trouble code output (? not documented for North American vehicles)
K	FSC	Trouble code output (cruise (speed) control computer)
L	-	Not Used
M	TAT	Diagnostic-mode input (automatic transmission control computer)
N	TBS	Diagnostic-mode input (anti-lock brakes (ABS) control computer)
P	TAC	Diagnostic-mode input (? not documented for North American vehicles)
Q	TWS	Diagnostic-mode input (? not documented for North American vehicles)
R	TSC	Diagnostic-mode input (cruise (speed) control computer)
S	-	Not Used
T	FAB	Trouble code output (air-bag diagnostic monitor computer)
U	IG-	Igniter coil output (for connection to external tachometer)
V	GND	Ground
W	TFA	Diagnostic-mode input (? not documented for North American vehicles)
X	F/P	Fuel pump relay coil (ground to activate fuel pump)
Y	TAB	Horn relay
Z	-	Not used
3	-	Not used

Interpreting the codes :

Automatic Transmission (ATX) Malfunction Codes

Automatic transmission codes can be read by connecting the TAT and GND pins (see above for the location of this pin) and watching the "hold" light on the instrument cluster. The codes are read exactly as they are when reading the engine codes, except that the Hold light flashes, not the Check Engine Light. You will find a complimentary PDF document at the top of the page with detailed instructions for each of the error codes.

A summary of the codes and the reasons :

Code	Affected System or Component
01	NE1 (crankshaft position sensor)
06	Vehicle speed sensor
12	Throttle position sensor
14	BARO sensor (located within PCME)
55	Vehicle speed pulse generator
56	ATF thermosensor
57	Reduce torque signal 1
58	Reduce torque signal 2
59	Torque reduced/ECT sensor
60	1-2 shift solenoid valve
61	2-3 shift solenoid valve
62	3-4 shift solenoid valve
63	converter lock-up solenoid valve
64	3-2 timing solenoid valve
65	converter lock-up valve
66	line pressure solenoid valve

Anti-Lock Braking System (ABS) Malfunction Codes

Anti-lock braking (ABS) system codes are read when the TBS and GND pins are connected in the Diagnostic connector (see above). The codes are read, again, like the engine codes, but now on the ABS light on the instrument cluster. You will find a complimentary PDF document at the top of the page with detailed instructions for each of the error codes.

A summary of codes and the reasons :

Code	Affected System or Component
11	Right front wheel speed sensor or rotor
12	Left front wheel speed sensor or rotor
13	Right rear wheel speed sensor or rotor
14	Left rear wheel speed sensor or rotor
15	Wheel speed sensor
22	Hydraulic unit harness
51	Fail-safe relay
53	Motor or motor relay
61	ABS control unit

Supplemental Restraint System (SRS) Malfunction Codes

The supplemental restraint (SRS), better known as "air bag" system will flash the highest priority code on the air-bag lamp on the dash with no need for any pin in the Diagnostic box to be grounded. The codes are read, again, like the engine codes, but now on the Air Bag light on the instrument cluster.

NOTE: these are from a 1993 Ford Service Manual. Later models with dual airbags (1994+) may have additional codes not covered here. Email me if you encounter one. Also, I hope but am unsure if these apply to the MX-6...

A summary of codes and the reasons :

Priority	Code	Fault
Highest	-	No air bag lamp: diagnostic monitor (DM), ignition power or bulb circuit
|	-	Continuous lamp: DM disconnected or inoperative
|	12	Low battery voltage
|	13	Air bag circuit or crash sensor shorted to ground
|	21	Safing sensor mounted incorrectly
|	22	Safing sensor: output shorted to battery voltage
|	23	Safing sensor input feed or return circuit open
|	24	Open in circuit 944B or low-resistance in crash sensor(s)
|	32	Driver's side air-bag / safing sensor: high resistance or open
|	33	Pin 7 not grounded at DM
|	34	Driver's side air-bag / safing sensor: low resistance or shorted
|	35	Low resistance across pins 8 and 9 of DM
|	41	Crash sensor circuit: high resistance or open
|	44	RH crash sensor not mounted properly
|	45	Center (radiator) crash sensor not mounted properly
|	46	LH crash sensor not mounted properly
|	51	DM internal fuse: blown and short to ground no longer exists
|	52	Backup-power supply: voltage boost fault
|	53	Internal DM fault
Lowest	-	Rapid continuous flashing or air-bag lamp: all crash sensors disconnected

Engine Management Malfunction Codes

There are quite a few codes. The following table shows the codes for the 1994 Probe GT (and a couple for the 1993) and what they mean, click on the code number to take you to the explanation and resolution.

Code	Circuit Diagnosed	Memorized
02	'NE2' crankshaft position sensor	Yes
03	'G' camshaft position sensor	Yes
04	'NE1' camshaft/crankshaft position sensor	Yes
05	Knock sensor	Yes
08	Volume Air Flow sensor (VAF)	Yes
09	Coolant temperature sensor (CTS)	Yes
10	Intake air temperature sensor (IAT)	Yes
12	Throttle position sensor (TPS)	Yes
14	Barometric pressure sensor	Yes
15	LHO2S inactivation error	Yes
16	Exhaust gas recirculation (EGR) system	Yes
17	LHO2S inversion error	Yes
23	RHO2S inactivation error	Yes
24	RHO2S inversion error	Yes
25	Fuel pressure regulator control solenoid	Yes
26	Canister purge solenoid	No
28	EGR vacuum solenoid	No
29	EGR vent solenoid	No
34	Idle air control (IAC) solenoid	No
41	VRIS #1 solenoid	No
46	VRIS #2 solenoid	No
67	LFAN relay (1993 only)	No
69	ECTF sensor (1993 only)	Yes

V6 Configurations

The V6 configuration appears in 1.8, 2.0, 2.25 and 2.5 litre displacements.

2.25 V6 - worlds only Miller-Cycle (MC) as opposed to Otto-Cycle engine. The Miller Cycle uses an 8 to 1 compression ratio with 10 to 1 power ratio for improved power & reduced fuel consumption. The MC uses a twin-intercooled Lysholm-screw Autorotor supercharger (world's most compact & most efficient) to deliver 210-230lb/ft at 3500rpm and 0-60 of 7.9secs from the 4-speed ATX. It effectively achieves the power of a 3.2 - 3.5 V6, yet fuel economy of a 2.1 V6. The 0-60 time through torque-converter slippage masks the accelerative capability.

2.5 V6 - two variations of the 2.5 V6 exist, KL for ex-Japan, KL-ZE for within Japan. The KL is a detuned variant of the KL-ZE offering power and fuel economy of a 2.2 V6 (based on the 2.0 V6 output). The KL-ZE offers 200bhp and achieves up to 94bhp/litre.

All V6s - all Normally Aspirated V6s feature a Variable Resonance Intake System (VRIS), the same concept as later used by Porsche on their 3.6 and Ferrari in much more sophisticated form on their V12. VRIS first appeared in Mazda's in their older 158bhp 2.0i-16 UK engine in 1989, it's purpose is to maximise the area under the torque curve rather than peak figures so aiding low-end driveability. In addition, the VRIS aids fuel efficiency and averages of 27-29mpg (Imperial) in urban driving and up to 32-34mpg (Imperial) on the highway readily attained.

The I4 engines are special derivatives of the Miata & 1.8 I4 235bhp turbo engines. The V6 has been used in the SuperTouring Mazda Xedos6 & 323 V6 5dr (Xedos6 floorpan, not related to the 323), and by Ford in 2.0 V6 form in Mondeo/Contour. The Mazda V6 is not related to the Duratec engine which lacks a forged crankshaft. The 2.5 V6 MX6 raced in several countries successfully. The IMSA 2.5 V6 engines produced 430 - 480bhp from the 2.5 V6, the 2.0 V6 was 380 - 420 bhp, all in race only form.

Engineering Data

Mean Piston Speed

• V6 Engines - all-alloy DOHC 24V 60-degree V6 configuration
• Split Crankcase - as 911 flat-6 offers increased rigidity over traditional bearing-cap solutions for high-rpm capability (7800rpm 2.0V6) and low NVH (winning 1992 German engine award)
• Bearings - 4-bolt Mains, with a further pair of bolts at each bearing section. Key journals & bearings are oversized regarding width. Bearings are triple-layer heavy duty
• Crankshaft - Forged, nitrided, triple-lapped, mirror-finished
• Piston Squirters - Upper bearing journals contain piston oil-squirters to aid cooling
• Exhaust-Valves - Stainless steel & sodium cooled
• Pistons - Lightweight to reduce reciprocating mass, piston skirts are moly coated to reduce friction
• Head Gaskets - Stainless steel is used, with torque-to-yield bolt
• Stroke - Very short stroke creates low crank angles & low rod/bearing loads

Engine Dynamic Stress Levels

Mean Piston Speed, MPS

• 2.5 V6 MPS = 0.167 * 2.92 * 7000 = 3170 ft/min at 7000rpm
• 2.0 I4 MPS = 0.167 * 3.62 * 6500 = 3929 ft/min at 6500rpm
• F1 engine MPS = 4519 ft/min at 16,400rpm

As a benchmark, MPS

• under 3,500 ft/min - Good reliability
• 3,500-4,000 ft/min - Stressing
• over 4,000 ft/min - Very short lived

Bore & Stroke

• 2.0 Bore*Stroke of 83x92mm (3.62" long stroke)
• 2.5 Bore*Stroke of 84.5x74.2mm (just 2.92" stroke)
• For comparison F1 engines have 70x42mm (1.65" stroke)

Ring Loadings Top-rings must balance high-rpm capability and wear, a thin ring allows high-rpm capability, too thin and wear becomes an issue. With reduced crank angles from a short stroke ring wear is reduced. A 1.5mm ring is beneficial over a 1.0mm ring for high-rpm.

Maximum-Piston-Acceleration (MPA):

• 2.5 top-ring - 1.49mm/0.06"

MPA Permitted = 77,000ft/sec^2
MPA Experienced = 51,354ft/sec^2 at 7000rpm

• 2.0 top-ring - 1.17mm/0.046"

MPA Permitted = 105,000ft/sec^2
MPA Experienced = 70,157ft/sec^2

The BMW M5 in comparison experiences MPA of 90,000ft/sec^2 on a 1.5mm ring.

Lighter rings create reduced accelerative forces, reduced ring/piston interface overheating and reduced hammering of the piston-ring-groove. Too light and ring longevity is adversely affected.

MPA = (rpm^2 * stroke"/2189)*(1/2A), A = ratio between rod-length-between-centres to stroke.

2.0 rod-centre-dist = 135mm; stroke = 92.0mm; A = 1.47

MPS-2.0 = (6500^2*3.62/2189)*(1.2*1.47) = 51,354 ft/sec^2

2.5 rod-centre-dist = 138mm; stroke = 74.2mm; A = 1.87

MPS-2.5 = (7500^2*2.92/2189)*(1.2*1.87) = 70,157 ft/sec^2

Both the 2.5V6 & 2.0I4 engines are engineered for longevity. The 2.5 engine is likely to be the longer lived engine subject to identical maintenance to the 2.0 engine. Mazda V6 engines are assembled entirely by robots, not humans, at the Osaka engine plant in Japan alongside Rotary engines.

Ford bench testing, with very minor changes, showed the V6 to be capable of continuous running at 8900rpm - well beyond redline 7500rpm.

SAE paper "SAE920677" covers detailed design of the engine.

Engine Longevity

Long Term Testing

A USA oil company researched engine longevity using their own oil :

"After 300,950 miles the Mazda MX6-V6 passed an IM 240 Exhaust Emission Test in Aurora, Colorado, with results well within new car limits. At more than 310,000 miles, the test engine was disassembled for inspection and measurement. No wear was evident on valve stems and guides, main and rod bearings, crankshaft main and rod journals, or cylinder walls. The cylinder hone marks from original factory machining were all clearly evident. While piston skirts showed no wear, piston rings showed an average of only 0.0015" of face wear."

The V6 rivals the Lexus V8 for longevity, which is unsurprising considering the original application was a Xedos6-2.0V6, Xedos9-2.25/2.5V6 & Sentia rotary luxury lines. Many V6s & I4s have exceeded 350,000 miles, the only failures on one was a Mitsubishi alternator at over 200,000 miles and the pre-Jan-1995 rear calipers on another.

The replacement for the V6 will come in two forms, a 2.3-DOHC-I4 in the Mazda-6 and a 3.0-DOHC-V6 in a larger saloon. There is of course the innovative 4 door sports car, the RX-8, with the 250-280bhp Renesis rotary engine and potential for a series of rotary sports cars should the market demand. The Renesis engine is a non-turbo rotary engine using side-port exhausts to greatly improve fuel economy, reduce emissions and improve performance.

Foreward

What follows is the originally submitted SAE by Mazda reagrds the KL series engine and goes into great detail. Re-formatted to fit onto this site and hosted for the benefit of the 'KL' engine community.

Mazda New Lightweight and Compact V6 Engines

Authors : Takashi Sakono, Shinobu Takizawa, Setsuo Harada, Tatsuji Ikeda, and Hiroshi Abe

Mazda Motor Corp.

ABSTRACT

Mazda has developed new-generation V6 engines. The new V6 series comprises 2.5-litre, 2.0-litre and 1.8-litre engines. The development objective was to ensure high output performance for excellent "acceleration and top-end feel", while satisfying "Clean & Economy" requirements. The engines also had to have a pleasant sound. Mazda selected for these engines a short stroke, 60? V-shaped 24 valve DOHC with an aluminum cylinder block. Various techniques are adopted as follows :

• Combustion improvement and optimization of control to achieve high fuel economy and low emissions
• Improvement of volumetric efficiency, inertia reduction of rotating parts and optimization of control to achieve excellent "acceleration and top-end feel"
• Adoption of a high-rigidity, two-piece cylinder block and crankshaft and weight reduction of reciprocating parts to achieve a pleasant engine sound
• Material changes and elimination of dead space to achieve a compact, lightweight engine

Introduction

These days, people are not as concerned with material wealth as they are with spiritual wealth. As for automobiles, there is a growing demand for a vehicle which can be deeply satisfying to drive and is environmentally safe (low emission and high fuel economy). V6 engines are becoming popular for their smooth and quiet characteristics. However, in the "family-use" and "compact-speciality" car classes, conventional V6 engines can not meet the lightweight, compact and pleasant drive requirements. Newly developed K-series engines are small, matching stylish and compact vehicles and appeals to the customer's sensitivity and is pleasant to drive. The K-series comprise 2.5-litre V6 DOHC(KL), 2.0-litre V6 DOHC(KF) and 1.8-litre V6 DOHC(K8) engines.

Development Objectives

To achieve drive feeling which appeals to total human sensitivity and as a contribution to the unique "low hood & short nose" styling, the following four major objectives were set in developing the K-series engines :

• Low fuel consumption, low emissions
• Excellent "acceleration and top-end feel" and pleasant engine sound
• Most compact and lightweight engine of all mass produced V6 engines
• Long-life durability with high performance

Main Specifications and Performance

To achieve high combustion efficiency, excellent acceleration and top-end feel, the K-series engines were designed with bore and stroke of 84.5 x 74.2 mm for KL, 78 x 69.6 mm for KF and 75 x 69.6 mm for K8. To contribute to the "low hood & short nose" vehicle style, 60-degree bank angles, which are superior in reducing vibration, noise, and packaging size, were selected.

Fig. 1 shows a sectional view of the KL engine and Table 1 shows the main engine specifications.

Fig. 1

To achieve excellent top-end feel in the high speed range while ensuring driving performance in normal operating range, high torque was realized in all engine speed ranges. The engine performance curves are shown in Fig. 2.

Fig. 2

The following represents the techniques employed in the K-series engines, focusing on the "KL" engine.

Table 1 Engine specifications

	KL	KF	K8
Type	Gasoline, 4-cycle	< --	< --
No. of Cyl. & Arrangement	6 cylinders, 60? V type	< --	< --
Displacement (cc)	2497	1995	1845
Bore x Stroke (mm)	84.5x74.2	78x69.6	75x69.6
Valve Mechanism	DOHC Belt-driven	< --	< --
Valves/Cyl.	4	< --	< --
Combustion Chamber	Pentroof	< --	< --
Compression Ratio	9.2	9.5	9.2
Max. Output (kW/rpm)	123/5600	104/6000	97/6500
Max. Torque (N ? m/rpm)	221/4800	170/5000	156/4500
Fuel System	EGI	< --	< --
Dimensions (L x W x H)(mm)	620x675x640	650x685x660	650x685x655

TECHNIQUES

LOW FUEL CONSUMPTION AND LOW EMISSIONS - Regarding "clean and economy" as basic requirements, work was done to improve combustion and optimize control.

Combustion improvement

Efforts were concentrated on the development of a combustion chamber which offers high thermal efficiency over the entire operation range with lowered emissions.

First, an optimum intake air throat diameter was selected to maintain volumetric efficiency in the high-speed range and maximize intake air flow velocity in the low- and mid-speed ranges, thus enhancing volumetric efficiency in all speed ranges with the output performance in high speed range being ensured. The valve angle was then narrowed for optimization and the combustion chamber made more compact (reduction of surface/volumetric ratio) to reduce cooling loss for higher thermal efficiency, without relinquishing adequate throat diameter. (Fig. 3) Squish area, which creates turbulance of the air/fuel mixture (squish) during the compression stroke, was given around the valves to ensure high volumetric efficiency and high combustion speed. (Fig. 4) (1) As a result, the combustion chamber is a compact pentroof with intake and exhaust valve angles of 27 degrees. Squish area to bore area ratio is 17.3% and the squish clearance is 0.68 mm. The throat diameter is 28.5 mm on the intake side; and 25 mm on the exhaust side. (Fig. 5)

Fig. 3

Fig. 4

Fig. 5

The emission of hydrocarbons has been greatly reduced by eliminating the crevice volume, the space around the piston top land, valves, and spark plug that extinguishes the flame. Fig. 6 shows the locations of these changes and the hydrocarbon reduction effect.

Fig. 6

Optimization of Control

To attain superior running performance, low fuel consumption, low emissions, and other targets, the overall control of KL engine is handled by a microcomputer. The main controls include those for fuel injection, air/fuel ratio feed-back, idle speed, EGR, Purge.

Each injector's fuel injection volume and timing were optimized by a multi-point sequential fuel injection system. The effect of this system on reductions of fuel consumption and emission depends on how air/fuel ratio is controlled to handle sudden changes in engine speed and load in acceleration and deceleration.

Presision of each bank's A/F ratio is enhanced with air/fuel ratio feed-back control made on right bank and left bank individually to reduce emission.

Improved control system made it possible to reduce idle engine speed and extend the engine speed range where fuel is saved, thus enhancing fuel economy.

EGR flow rate is optimized by electronic control of the duty-solenoid valve as required for engine speed and load to achieve low emissions and low fuel consumption.

The evaporated fuel absorbed in the canister is sent to the engine via the solenoid valve to avoid gasoline volatilization. Fig. 7 shows the engine control systems.

Fig. 7

LIGHTWEIGHT

KL engine became the lightest in their displacement classes among V6 engines by the implementation of several measures: using aluminum alloy for the cylinder blocks and auxiliary brackets; resinating the belt cover and airflow meter; utilizing a short stroke; integrating the inlet manifold and surge tank; and decreasing the exhaust manifold size.

Fig. 8

EXCELLENT ACCELERATION AND TOP-END FEEL

To improve drive feeling, much effort was put into achieving excellent "acceleration and top-end feel." Fig. 8 shows a quantitative method that uses vehicle acceleration characteristics in which "response" and "acceleration" make up "acceleration feel"; and the area of further extension from the top of vehicle acceleration curve, makes up "top-end feel". (2) The object was to get smooth vehicle acceleration characteristics in the "response" area, powerful and linear vehicle acceleration in the "acceleration" area, and to keep high vehicle acceleration characteristics in "top-end feel" area. These objects were attained by ensuring high continuous torque characteristics in all engine speed ranges, reducing the inertia weight of rotating parts, and optimizing ignition timing. (Table 2)

Table 2 Techniques for improvement of acceleration and top-end feel

	Acceleration feel		Top-end feel
	Response	Acceleration
Torque improvement techniques	XX	XX	XX
DOHC 24valve	X	X	X
Short Stroke	X	X	X
Weight reduction of rotating parts	XX	X	X
Active IG timing control	XX

High Continuous Torque Characteristics

Fig. 9

Efforts were concentrated on the improvement of volumetric efficiency and the optimization of setting. The technical features incorporated in each area are shown in Table 3.

Table 3 Techniques for torque enhancement

	Engine speed
	Low	Mid	High
4-stage VRIS	X	X	X
Semi-dual exhaust system		X
Crank angle sensor			X
Trace knock control	X

To obtain high torque in all engine speeds, a multi-stage Variable Resonance Induction System(VRIS) was adopted in the intake system. In the VRIS, surge tanks in both banks were connected to each other by resonance tubes. The resonance induction generates high torque characteristics around the resonant frequency. The resonant frequency changes by changing the tube's length.(3) Each resonance tube of multi-stage VRIS has a switching valve, which are operated according to the engine speed and load. And the system of multi-stage VRIS changes the resonant frequency to use the effect of resonance charge in all engine speed ranges. In the K-series engines, to optimize the resonance effect with small packaging size, the length of each resonance tube was optimized by simulation research.(Fig. 9)

Because the switching valves are operated according to driving conditions, it is possible to utilize the different resonance tube characteristics, thus realizing smooth and high torque in all engine speed ranges. The structure of VRIS is shown in Fig. 10. Fig. 11 shows the valve drive controls and 4-stage VRIS torque characteristics in low, mid and high speed ranges.

Simulation was also utilized to optimize the exhaust system specifications, obtaining exhaust-pulse scavenging in the desired engine speed ranges as shown in Fig. 12.

By adopting the semi-dual exhaust system in which two exhaust pipes have almost the same length, torque was raised in the desired, mid speed range. (Fig. 13)

Fig. 10

Fig. 11

Fig. 12

Fig. 13

Ignition control was optimized to raise torque in low and high engine speed ranges. First, to improve the control of ignition timing in the high speed range, a new direct crank-angle- detection method (crank-angle-sensor) was chosen over the conventional method, in which the angle was detected by a distributor attached to the camshaft. (Fig. 14) Fig. 15 shows the effect of the crank angle sensor on torque enhancement.

Fig. 14

Fig. 15

With trace knock control, a single sensor between the engine V-banks detects small knocking, and the ignition timing is then set at a point just prior to the generation of the knocking in low speed ranges. In the conventional method, ignition timing was set in consideration of engine compression ratio and fuel octane number. (Fig. 16) The trace knock control optimizes ignition timing. And this optimizes engine potential, which in turn raises torque. (Fig. 17)

Fig. 16

Fig. 17

Reduction of Inertia Weight of Rotating Parts

24-valve DOHC short stroke was adopted as the basic specifications. Furthermore, the rotating inertia weight of the flywheel, crankshaft, and connecting rod was drastically lowered by making full use of Finite Element Method (FEM) analysis and acceleration response was greatly improved.

Fig. 18

Optimization of Control

Ignition timing is actively controlled with crank angle sensor which detects changes in angular velocity of engine during acceleration; if vehicle vibration is generated, the timing is retarded, thus quickly converging vehicle acceleration value fluctuations which diminish acceleration feel, and improving acceleration in response area. (Fig. 18)

Because of the above new technologies and structure, KL engine can deliver the demanded torque characteristics and acceleration performance, while maintaining high and smooth acceleration characteristics.

PLEASANT ENGINE SOUND

Great efforts have been made not only to reduce engine vibration and noise levels but also to produce a more pleasant engine sound. To realize these objectives, engine development efforts were concentrated on the following two areas: 1) elimination of unpleasant rumbling sounds and 2) reduction of low-frequency sounds. Table 4 shows the incorporated techniques and the objectives.

Table 4 : Techniques for sound quality improvement

Technical menu	Decrease of rumbling noise	Decrease of low frequency noise
Lower block	X
No.4 journal widened up	X
Forged steel crankshaft	X
Lightweight piston & conn-rod	X	X
Increased transmission coupling rigidity		X

Fig. 19

Elimination of Rumbling Noise

Unpleasant rumbling noises are often caused by crankshaft bending vibration due to flywheel face runout. This vibration is propagated through the cylinder block main bearing, block body, engine mount and vehicle body and results in an unpleasant rumbling interior noise. To reduce the noise, the engine mount's vibration level (inertance level), which responds to excitation in the cylinder, should be lowered.

Fig. 19 shows the engine mount vibration level when each cylinder is excited, the resonance mode increases the vibration level of the nonfundamental order components at which the unpleasant sound is often noticed. (4) To improve the flywheel resonance mode, that is, to reduce the inertance level and increase frequencies, cylinder block rigidity and crankshaft support rigidity of the main journal were increased.

The vibration characteristics depends on dimensions and configurations, and the optimal configurations were studied through FEM analysis. As a result of the study, a two-piece cylinder block was employed to increase rigidity of both the cylinder block itself and its crankshaft supporting area. The cylinder block was divided into upper and lower sections at the crank center face and the lower block was given a ladder frame construction integrating the main-bearing cap and bearing beam.

Fig. 20 shows a comparison of rigidity between the cast-iron cylinder block and the two-piece cylinder block employed in KL engine. The conventional cast-iron cylinder block was fitted with a bearing beam and a plate connecting the cylinder block skirts to increase the rigidity of the cylinder block itself. Generally, open-decked aluminum cylinder blocks give a lower rigidity than cast-iron blocks. Nevertheless, by adopting the new cylinder block construction, the natural frequency of the block itself was increased.

For further reduction of flywheel face runout, the lower deck's No.4 journal near the flywheel was made wider than the other journals. In addition, a forged steel crankshaft was used to increase crankshaft bending rigidity. Fig. 21 shows the reduced inertance level and the increased frequency of flywheel resonance mode. By improving the vibration transmission structure, nonfundamental order components decreased from those of cast-iron block with the conventional construction. (Fig. 22)

Fig. 20

Fig. 21

Fig. 22

Reduction of Low-Frequency Noise

To reduce low-frequency noise, particular attention was paid to the second order components. To do this, powerplant bending (PPB) vibration and second-order inertia couple were reduced.

To reduce PPB vibration, coupling areas between the cylinder block and transmission should be made highly rigid. Transmission coupling rigidity was understood to be increased effectively by lengthening the cylinder block skirt and widening the coupling flange (cone flange). Fig. 23 shows the improvement effect of the above changes on in-line 4-cylinder engines' PPB vibration level calculated with FEM.

Fig. 23

Based on these results, PPB vibration in the KL engine was reduced by adopting a cone flange with high rigidity as well as a longer skirt. Fig. 24 shows the PPB natural frequency characteristics of the KL engine. PPB resonant frequency was increased to the point where no resonance was produced in the engine operating speed range (less than 7,500 rpm) - even with second-order excitation.

To decrease second-order inertia couple, piston and connecting rod weight, which cause excitation, were reduced by making full use of FEM analysis. As shown in Fig. 25, the reciprocating inertial weight of the piston and connecting rod is lower than all the other reciprocating inertia weight with equal diameter. Because of the reduction of PPB vibration and second-order inertia couple, the KL engine reduces the second-order vibration level which causes most low-frequency noise.

Fig. 24

Fig. 25

COMPACTNESS

To match the low hood & short nose vehicle style, the engine height, width and length were reduced. With a unique direct valve drive, combined with the adoption of a compact intake manifold and a compact cylinder block, the low hood could be realized. The valve drive system, as shown in Fig. 26, employs gears which directly engage each bank's intake and exhaust camshafts, and a timing belt attached to the rear bank's inner camshaft and the front bank's outer camshaft. This layout made it possible to reduce the height of the engine front as shown in Fig. 27. Also, this system, along with the adoption of a compact exhaust manifold, has reduced engine width. The combination of these design features gives KL engine the most compact packaging sizes in their displacement classes.

Fig. 26

LONG LIFE AND MAINTENANCE-FREE

Efforts were made to extend the life of these engines and make them as maintenance-free as possible so that customers can be pleased with the vehicle's quality long after the initial driving period.

Long Life : The following achievements were made to ensure extended low engine oil consumption: Piston land volume and piston ring configuration were optimized through simulation analyses for stable ring behavior; and wear resistance of the cylinder liner was improved by the use of alloyed cast-iron.

The oil seal material (camshaft and crankshaft oil seals) was changed to fluorine to improve thermal resistance.

Maintenance-Free : Mazda's unique ventilation system comprises a PCV valve in the left bank and a forked ventilation hose connecting the air hose and both banks, providing the right bank a higher rate of air flow than the left bank (7:3). With this mechanism, fresh air flows in the crankcase and cylinder head cover effectively, thus ensuring stable oil characteristics.

A timing belt having STS-teeth and a hydraulic auto tensioner were designed as follows to have long-life quietness :

• Optimization was made on timing belt pitch, ejector force and leak-down time of the auto tensioner.
• H-NBR having high heat resistance and glass fiber having high bending resistance were used for the timing belt, realizing the reduction of belt width to 30mm while ensuring a satisfactorily long life.

Fig. 27

The Hydraulic Lash Adjuster (HLA) has oil recirculation passages in its plunger to recycle the less-air-contaminated oil in the high-pressure chamber. This construction minimizes the influence of air-contaminated oil -- even in the engine-startup condition with high-air-contaminated oil -- resulting in improved quietness and the elimination of the need for valve clearance adjustment.

MAIN STRUCTURAL COMPONENTS

In this section, techniques other than those discussed above are summarized on the basis of components and systems :

BASIC ENGINE

Cylinder Block

Die casting was utilized in the production of the aluminum cylinder block. Making use of this method's high precision and ability to produce thin-walled components, a lightweight cylinder block was realized.

In the upper block, a 3mm-thick cast-iron cylinder liner is cast-in to add durability, and plateau honing with a GC grindstone is performed for the liner to stabilize initial oil consumption. A siamese open deck with optimized liner thickness and bolt pattern ensures cooling between bores and suppression of liner deformation. In the lower block, a cast-iron main bearing cap is cast-in to control main bearing clearance fluctuations resulting from temperature changes. This new Mazda technology has been implemented to achieve quietness and improve reliability.

Fig. 28

Cylinder Head

Low-pressure casting was utilized to refine the aluminum micro-structure, improving strength and thus reliability. Further, AC4D, with its superior thermal conductivity, is used to improve antiknock performance.

The gear housing is mounted on the front of the cylinder head and is supported on both sides of the gears by camshaft caps. In addition, a camshaft cap beam which attenuates gear engagement vibration is used on the right bank to improve supportability (Fig. 28)

The engine's asbestos-free laminated cylinder head gaskets are composed of two sheets of stainless steel and have the ability to resist the high explosive pressures of the combustion chamber. They form an effective seal against oil and water leaks, and pose no threat to the environment. The cylinder head bolts, which join the cylinder head and cylinder block, are tightened in the plastic region to stabilize axial forces.

Camshaft Friction Gear

Between the two camshafts are drive and driven gears with 55 teeth each and a friction gear with 56 teeth. The friction gear, superimposed on the driven-gear by spring force, was designed to be free from backlash with its extra tooth. The friction resulting from this structure absorbs fluctuations in drive-gear rotation, effectively suppressing gear rattle noise. In addition, tooth flank precision is optimized through simulation techniques to eliminate gear engagement noise. (Fig. 29)

Fig. 29

Piston

The die-cast aluminum short-skirt pistons developed are light and yet reliable for continuous high-speed operation. The piston rings comprise two compression rings and one oil ring. By applying Molybdenum disulfide coating on the sliding face of the piston skirt, a decrease in piston clearance was achieved with no increase in sliding resistance, thus preventing piston "slapping." This results in improved quietness in the high-speed range.

Connecting Rod

To reduce both weight and weight variation, a weight adjustment cut-off boss is mounted to the large end, with the actual adjustment taking into account the weight variation of the small end. A connecting cap is joined to the rod by means of plastic-region tightening bolts (without nuts). This tightening method reduced weight in the large end and ensures highly stable axial forces.

Crankshaft

To ensure reliability, the crankshaft is composed of forged steel; five counterweights are adopted to achieve light-weight; the bearing fillets are heavy-duty rolled to increase fatigue resistance; the journals are high-frequency hardened, then mirror finished; and heavy-duty three-layer copper-lead bearings are used to ensure adequate durability.

Fig. 30

LUBRICATION SYSTEM

Mounted to the front of the engine is a highly efficient trochoid oil pump, which is directly driven by the crankshaft and has nine internal and ten external teeth. To reduce vibration and noise caused by oil pressure fluctuations on the delivery side, the clearance with the inner rotor on the crankshaft was adjusted and the configuration of the partition between the suction and delivery sides was optimized.

To control output loss caused by crankshaft oil diffusion and to reduce the amount of air in the oil, superior oil baffle plate configuration has been adopted. Combined with the revision to the oil strainer configuration, it ensures stable pressure even when the oil level varies during high-speed cornering.

A water-cooled oil cooler and piston-cooling oil jet are employed to increase durability against high-temperature loads. (Fig. 30)

COOLING SYSTEM

A belt-driven centrifugal pump supplies coolant evenly to the left and right banks. To prevent the temperature of the coolant in the cooling circuit from rising too rapidly, such as during a cold start, an inlet thermostat mechanism is utilized. Adoption of a two-stage electric cooling fan brought about noise reduction. (Fig. 31)

FUEL SYSTEM

A microcomputer-controlled sequential electronic fuel injection system containing several unique characteristics has been adopted. First side-feed method, where fuel is supplied from the side of the injectors, is used to reduce the discharge of vapor produced from rising fuel temperatures. This results in improved engine restartability after high-speed and/or high-load driving. Second, the weight of the injector's mobile parts has been reduced to improve response and lessen operating noise. Third, an internal fuel control mechanism is utilized to ensure that injected fuel quantities will not change with vehicle age. Finally, a harness attached to fuel distribution pipe improves the exterior view of the engine and adds to its compactness.

Fig. 31

MANUFACTURING INPUT

To guarantee top-quality engines, several manufacturing technologies had to be developed.

Casting Techniques

To obtain consistently high quality, automatic casting of the cylinder head and cylinder block was introduced. All important technical casting data such as mold temperatures and pressures, are fed back to the control unit.

Machining Techniques

The following highly precise machining techniques were adopted to ensure high reliability under high-load/speed driving conditions: Precise mirror-like surfaces of the crankshaft pins and journals with oil passages are obtained from triple-lapping and a precise surface of the cylinder block main bearing is achieved through triple-honing. Simulating the conditions when head bolts are tightened, machining of the holes in the cylinder head cam journals is done to prevent changes in precision caused by tightening head bolts.

Assembling Techniques

To obtain consistent product quality in the production line in which various types of engine are produced, 60% of the assembly line for K-series engines are controlled automatically by computer.

CONCLUSION

The K-series engines contain all the design techniques Mazda has developed, including combustion chamber, intake/exhaust systems, electrical controls, noise reduction and reliability, for high performance engines.

The K-series engines described in this paper are mounted in the new Mazda 626, MX-6 and MX-3 vehicles. The authors are quite confident that the various development objectives required to these vehicles have been achieved at a high level, making use of the above techniques. The following four points summarize the accomplishments made in developing the K-series engines.

• K-series engines have achieved low fuel consumption and low emissions by adopting a compact, high-squish combustion chamber and optimizing all controls by microcomputer.
• High smooth vehicle acceleration characteristics that give excellent "acceleration and top-end feel" have been gained because of two improvements: a compact design that makes full use of intake and exhaust dynamic effect; and an engine control system that optimizes ignition timing.
• With a more rigid cylinder block and a more rigid crankshaft support structure, low-frequency noise was reduced and rumbling noise suppressed, resulting in a pleasant engine sound.
• A design that aimed for reduced weight and compactness, realized by such modifications as an aluminum cylinder block and an integrated surge tank/inlet manifold, has made the K-series engines the lightest and most compact in the same displacement class of V6 engines, thus contributing to improve fuel consumption and realize a lower hood styling.

ACKNOWLEDGEMENTS

The authors would like to express their gratitude for the full support given by all those inside and outside of Mazda involved in the development and production of the K-series engines.

REFERENCES

• N. Hashimoto et al., "Development of High Efficient Combustion Chamber for 4 Valved Engine", The 9th Internal Combustion Engine Symposium, Japan, 1991, pp. 233 - 238
• H. Yamamoto et al., "A Study Based on Investigation of Consciousness for Drive Feeling", Mazda Technical Report, No.4, 1986, pp. 3 - 10
• K. Hatamura et al., "Mazda's New V-6 Gasoline Engine and Its Innovative Induction System", SAE Paper No. 871977
• H. Abe et al., "Study on Evaluation and Improvement of Acoustic Quality in Vehicle Passenger Compartment", Mazda Technical Report, No.6, 1988, pp. 44 - 51

Sockets

USA - Facom or Snap-On, UK BriTool. Ideally pick tools where the socket grips the flat of the nut rather than the edge of the nut (thus doesn't round them off and transmits more torque, thus better from an ergonomic perspective).

• 10mm - 12pt - interior & underhood nuts, undertray plastic, battery terminals & cold air duct on radiator.
• 12mm - 6pt - airbox bolts & nuts, ABS connector fittings.
• 14mm - 6pt - high quality - strut top nuts, antiroll bar linkage nuts & bushing nuts/bolts.
• 14mm - 6pt deep - high quality - antiroll bar linkages & bushing nuts/bolts.
• 17mm - 6pt - high quality - suspension components, last tightened 50yrs ago.
• 19mm - 6pt - high quality - suspension components, last tightened 50yrs ago.

Open/Closed Wrenches

10mm, 12mm, 14mm, 17mm, 19mm

Extensions & Adapters

• 12" extension - spark-plugs & airbox bolts/nuts (car tool kit has spark-plug wrench).
• 5" extension - general use.
• 1/2" & 3/8" - high quality - general use, spares in case one fails
• 1/2" breaker bar - high quality - removes Ingersoll-Rand-T9000 tightened nuts.

Torque Wrench

Dial-type are more popular than the beam but verify quality. Do not drop a wrench or leave it set on a high setting for long, or use it as a breaker bar.

Ratchet

Choose a ratchet as large a number of click-intervals in one rotation as possible. This provides good tactile feedback, easier/faster usage.

Oil Filter Wrench

The ideal oil filter wrench is a dealer item or "cap wrench". These are a short socket-type wrench that fits on the end of the oil filter easing fitting & removal. The official Mazda item for USA filters only is 7.49$US from Trussville Mazda, Part # 49-G014-001.

Hydraulic Jack & Jack Stands

Cheap ?20/US$30 hydraulic jacks are unsuitable, with far too small jacking platforms. Instead source from a larger more stable unit from "Motor Factors"/trade/retail suppliers.

Appropriate jack stands have a minimum of 2-tonne rating, large stance and wide flat U-top. They should only be used at the appropriate points only and on firm ground. Ensure your jack can lift high enough to get the stands under. Jack stands under suspension arms will crack & destroy the arms.

Hydraulic Jack & Safety Stand Positioning

The graphic below illustrates Jacking points & jack stand points. The car's scissor jack uses it's own specific jacking points too.

Cheap hydraulic jacks should not be used - they are unstable. Trade suppliers offer a range of discount workshop-style jacks.

A complimentary PDF file containing full jack and support areas and important safety information can be found at the top of this page.

Springs

Eibachs springs for MX6/626 reduce ride height 25-30mm (UK) or 25mm (US). H&R offer 35mm drop for the UK. On both, cutting the foam-antiroll-stops regains some lost suspension travel however on EU-Eibachs their spring-rate is too low to allow this without a harsh spring-rate transition point resulting. Eibach-US springs are similar to the softer US (not Euro) M3 springs, although they will provide less wallow/plough than the low US M3 front-rate.

Alternative approaches use adjustable coil-over systems. These range from Ground Control T6061 Anodised aluminium adaptors using 2.5" springs, through to true double-adjustable coilover-shocks from LEDA, AVO and others using 2.25" springs.

The rates of the various spring options are shown below graphically with regard to their profile and suspension travel.

All Linear Spring Rates

The use of an all linear spring rate, eg, very long spring (8"), with sufficient rate (325lb/in for V6s), and slightly-soft dampened (Tokico-3) provides an excellent compromise between ride & handling. The use of very long springs is unconventional and breaks the miss-perception of single "high" rates being rough. The miss-perception assumes little travel and that the stock spring-rate is 190lb/in, when in reality the anti-roll foam-stop rate (300lb/in+) is additive resulting in 490lb/in+ rates. To contrast the EU-Eibach rate is even higher than a single 500lb/in rate.

Ride

An all-linear rate combined with considerable travel avoids harshness due to sudden rate transitions and limited suspension travel. Such travel is the key as hitting a pothole at 60mph even with a 325-rate, uses up a full 2" of travel (linear potentiometer datalogging). In corners an all-linear rate shines, as potholes in the corner feel no worse than if impacted on in a straight line. Such a linear ride even in corners is something that the stock suspension can not achieve, instead crashing into the foam antiroll stops. The dampening rate is slightly under-dampened to eliminate vibration, passengers being left to enjoy the remaining taut yet unnervingly supple ride over potholes.

Handling

An all-linear rate provides for the most predictable handling possible, quite unlike other road cars and much easier to drive and co-operative when called upon in emergency maneouvres. The rate is sufficiently high to limit roll below most other spring options both at low & normal speeds, and only at very high cornering speeds will roll be greater - considering most peoples driving habits this is a reasonable compromise.

Dampening

Non-linear rates require shock absorbers to be either under-dampening when the rate is high or over-dampening when the rate is soft, with both wallow & harshness quickly resulting from poor compromises. The benefit of the reduced load on shock absorbers & linear rate is audible, with reduced rattles.

Spinal Advantage

Drivers or passengers with spinal problems will probably prefer an all linear rate, as it does not load the body with jolts from sudden rate-increases. For example, softer dampening on stock suspension can be counter productive: the higher rate is impacted on more per unit time due to the reduced dampening (ironically). A 8"-300lb/in rate will ride better but provides less road feel, and less travel so custom 8.5-300s are probably the ideal unless real coilovers are used.

Real coilovers

Real coilovers (LEDA, AVO, etc) allow the use of a tender/main spring setup (225/450lb/in) or progressive-tender/main setup (170/250/450) so with tuning a better ride (softer-initial) and handling (less roll) can be achieved. The stock anti-roll kinaesthmatic foam-stop solution follows this school of thought, but lacks tuning and later 95+ cars simply raised ride height in an awful aesthetic/handling attempt to improve ride: kin-unaesthetic stops. Many prefer all-metal spring solutions as the foam-stops vary in rate with temperature, just as wheel-rate (tire/tyre) varies similarly and the ride can be better on a warm day with with warm tyres than a cold day with cold tyres. The true ideal is a custom taper-wound spring (as used by Porsche on the 935) which has no sharp transition points to deteriorate handling or ride.

Anti-roll Bars

Anti-roll bars have a benefit for road cars in providing only an increased spring rate in corners, thus having less impact on ride than typical uprated springs. Offerings range from Eibach (Xedos6/MX6/626/PGT in Europe) with 19mm rear and uprated front bar, to Mazda Competition rear bar (16mm) and Addco rear bar (22mm), stock rear being a toothpick or 12mm in size. Eibach Europe delivery timeline on bars is several months.

Torque Specs

Ignition Area

• Distributor Cap torque bolts - 19-25Nm, 14-18lb/ft.
• Spark Plug Torque - 15-22Nm, 11-16lb/ft with engine cold (hot aluminium tears)

Exhaust Area

• Exhaust stud tightening torque - 2.5V6 - 19-25Nm, 14-18lb/ft in 2-3 steps
• Exhaust stud tightening torque - 2.0I4 - 20-28Nm, 14-18lb/ft (Nut), 16-22Nm, 12-16lb/ft) (Bolt) in 2-3 steps

Coolant Area

• Block Drain, right side of 2.5V6 engine - 19-25Nm, 14-18lb/ft
• Thermostat bolt 19-25Nm, 14-18lb/ft
• Water (Fan) Thermosensor - 16-23Nm, 12-17lb/ft

Oil Area

• Oil Pressure Sender - 11.8-17.7Nm
• Oil Filter Torque - 14-17Nm
• Oil Pan Drain Plug - Nm
• MTX Drain & Fill Plug - 40-58Nm, 29-43lb/ft

Airbox Area

• Fresh Air Duct across radiator - 7.8-10.7Nm; 10mm skt
• Airbox bolts & nuts - 19-25Nm, 14-18lb/ft; 12mm skt

Seatbelt Area

• Seat Belt Anchoring Points - 38-54Nm, 28.2-29.8lb/ft

Wheel Area

• Wheel lug nut - 89-117Nm, 66-87lb/ft
• Front & Rear Suspension Strut Bottom Two Cross Bolts - 94-116Nm, 69-86lb/ft; 19mm skt
• Front & Rear Antiroll Bar Linkage Nuts & Bracket Nuts/Bolts - 37-53Nm, 27-39lb/ft
• Front & Rear ABS Sensor lead strut bracket - 16-22Nm, 12-16lb/ft
• Front Calliper Guide bolts - 44-49Nm, 33-36lb/ft
• Rear Calliper Guide bolts - 34-39Nm, 25-29lb/ft
• Front Calliper Bracket bolts - 78-102Nm, 58-74lb/ft
• Rear Calliper Bracket bolts - 45-67Nm, 33-49lb/ft
• Front & Rear Calliper Bleed Screw - 6.9-9.8Nm
• Front Tie-Rod End to Tie-Rod - 69-98Nm, 51-72lb/ft
• Front Tie-Rod End (Cotter Pin locked) - 31-44Nm, 23-33lb/ft
• Flexible Brake Line to Fixed Brake Line - 12.8-21.5Nm
• Front & Rear Flexible Brake Line to Calliper - 22-29Nm, 16-22lb/ft
• Front & Rear Strut-Top nuts - 46-63Nm, 34-46lb/ft
• Steering Wheel Centre Lock Nut - 39-49Nm, 29-36lb/ft
• Steering Rack Mount Bushings (Type I & II) - 36-54Nm, 27-40lb/ft

Technical Data

Ignition Area

• Spark-plug gap: 1.0-1.1mm on 2.0 & 2.5
• Spark plugs - 2.5: NGK ZFR5F-11 (standard), NGK ZFR6F-11 (for UK & USA)
• Spark plugs - 2.0: NGK BKR5E-11 (standard), NGK BKR6E-11 (for UK & USA)
• Ignition Timing - 2.5V6 - 10 +/- 1 degree; ECU modifies between 6-8o degrees.
• Ignition Timing - 2.0I4 - 12 +/- 1 degree, not ECU modified (no knock sensor)

Cooling System Area

• Coolant Capacity - 2.5V6 - 7.5litres
• Coolant Capacity - 2.0I4 - 7.0litres
• Thermostat 2.0I4 & 2.5V6 - Initial-opening 80-84oC, full-open 95oC, full-open lift 8.5mm Fan operation temperature 2.0I4 - Approximately 97oC at the radiator cap filler neck
• Fan operation temperature 2.5V6 - Approximately 100oC at the radiator cap filler neck
• Fan Motor - 2.0I4 - MTX Single Speed, 5.8-7.6Amps, ATX Two Speed, 8.0-14.0Amps; 11.5-17.5Amps
• Fan Motor - 2.5V6 - MTX Two Speed, 8.0-14.0Amps & 11.5-17.5Amps, ATX Two Speed, 7.9-13.9Amps & 13.2-19.2Amps
• Water (Fan) Thermosensor - 2.0I4 - 91oC 1.70-1.84Kohm; 97oC 1.42-1.53Kohm; 108oC 1.03-1.11Kohm
• Water (Fan) Thermosensor - 2.5V6 - 91oC 1.70-1.84Kohm; 97oC 1.42-1.53Kohm; 108oC 1.03-1.11Kohm

Oil System Area

• Oil Capacity - 2.5V6 - Engine+Filter 4.0litres
• Oil Capacity - 2.0I4 - Engine+Filter 3.5litres
• Oil Dipstick L to F mark represents 1-litre
• Oil Pressure Specs - 2.5V6 - 28psi @1000rpm, 49-71psi @3000rpm
• Oil Pressure Specs - 2.0I4 - 57-71psi @3000rpm
• HLA Wear Limit - 0.18mm, replace at 0.15mm (feeler guage between slowly-rotated cam & HLA)
• MTX Oil Capacity - 2.7litres

General Specs 2.5 V6

• Valve Timing - Intake - Open BTDC - 8 degrees, Close ABDC - 50 degrees
• Valve Timing - Exhaust - Open BBDC - 54 degrees, Close ATDC - 8 degrees
• Bore & Stroke - 84.5mmx74.2mm, 3.33"x2.92"
• Spec Compression - 9.2:1; pressure 203psi at 250rpm, min 142psi at 250rpm
• Throttle Body - 2.5V6 - 60mm dia

General SPecs I4 2.0

• Valve Timing - Intake - Open BTDC - 8 degrees, Close ABDC - 47 degrees
• Valve Timing - Exhaust - Open BBDC - 50 degrees, Close ATDC - 5 degrees.
• Bore & Stroke - 83mmx92mm, 3.27"x3.62"M
• Spec Compression - 9.0:1; pressure 171psi at 300rpm, min 119psi at 300rpm
• Throttle Body - 2.0I4 - 55mm dia

Fuel System Area

• Fuel Pressure Regulator - 2.0I4 - 37-36psi
• Fuel Pressure Regulator - 2.5V6 - 41psi
• Max Pump Pressure - 2.5V6 - 72-92psi
• Max Pump Pressure - 2.0I4 - 64-85psi
• Injector Resistance - 2.0I4 - 12-16 Ohms at 20oC
• Injector Resistance - 2.5V6 - 12-16 Ohms at 20oC

Power Steering Area

• Power Steering Fluid - ATF Dexron-II or M-III
• Steering Wheel Free Play - 0-30mm

Brakes Area

• Master Cylinder i.d. 23.81mm, 0.937"
• Front Disc - Cylinder Bore - 57.15mm, 2.250"
• Front Disc - Pad Dimensions - 4800mm^2 & 10mm thick
• Front Disc - Dimensions - 258mm x 24mm (Probe/MX6 can be 264mm)
• Rear Disc - Cylinder Bore - 30.16mm, 1.187"
• Rear Disc - Pad Dimensions - 2900mm^2 & 8mm thick
• Rear Disc - Dimensions - 261mm x 10mm
• Power Brake Unit - MTX - 239mm, 9.4"; ATX - 188+215mm, 7.4+8.5"
• Brake Pedal Lever ratio - 4.1, Max Stroke 125mm, 4.92"

Wheels

• Tyre Rotation - 6200 miles
• Wheel Imbalance - max at wheel edge on 15" wheel - 9 grammes
• Front Wheel Alignment - Toe-in - 3mm +/-3mm
• Front Wheel Alignment - Camber - MX6: -0o42' +/- 45'; 626: -0o36' +/- 45'
• Front Wheel Alignment - Caster - MX6: 3o01' +/- 45'; 626: 2o37' +/- 45'
• Front Left/Right differences - Camber: 30' max, Caster: 45' max
• Rear Wheel Alignment - Toe-in - 3mm +/-3mm
• Rear Wheel Alignment - Thrust Angle - 0o +/- 0.1o

Manual Gearbox Ratio's

94 UK 626V6-2.5	94 UK 626I4-2.0	94 UK 626I4-1.8
1st - 3.307	1st - 3.307	1st - 3.307
2nd - 1.833	2nd - 1.833	2nd - 1.833
3rd - 1.310	3rd - 1.233	3rd - 1.233
4th - 1.030	4th - 0.914	4th - 0.914
5th - 0.795	5th - 0.717	5th - 0.717
Rev - 3.166	Rev - 3.166	Rev - 3.166
Fin - 4.105	Fin - 4.105	Fin - 3.850

VRIS System

RPM	0-3250	3250-4250	4250-6250	6250-7500
VRIS#1	Closed	Open	Open	Closed
VRIS#2	Closed	Closed	Open	Closed