ENGINE COMPRESSION
Check engine compression with engine at normal operating temperature, all spark plugs removed, fuel injector harness disconnected and throttle wide open.
Note. Connect coil high tension wire to ground before cranking engine for compression test.
| Application | Specification | |
|---|---|---|
| Compression Ratio | 10.3:1 | |
| Compression Pressure | ||
| Normal | 156-228 psi (11-16 kg/cm 2 ) | |
| Minimum | 128 psi (9 kg/cm 2 ) | |
| Maximum Variation Between Cylinders | 44 psi (3 kg/cm 2 ) | |
COMPRESSION SPECIFICATIONS
VALVE CLEARANCE
Model uses hydraulic valve lifters. No adjustment is necessary.
| WARNING: | If lifters are replaced, DO NOT start engine for 30 minutes, as valves may hit pistons. Lifters must be allowed to bleed down before starting engine. |
IGNITION TIMING
Ignition timing is electronically controlled and cannot be adjusted. See IDLE SPEED & MIXTURE.
IDLE SPEED & MIXTURE
Note. Mixture adjustment is not a part of normal tune-up procedure and should not be performed unless mixture control unit is replaced or vehicle fails emissions testing.
Note. Idle speed is electronically controlled and cannot be adjusted.
Scheme 1
Scheme 2
- Ensure engine is at normal operating temperature. Turn ignition off. Ensure all electrical accessories and cooling fan are off. Remove adjustment screw cap and pry out plastic plug from CO potentiometer installed in MAF housing. (Scheme 1)
- Connect CO tester to CO tap tube on right exhaust manifold. (Scheme 2) Read and record CO content. Repeat test on left CO tap tube. Content must be 0.3-1.2% by volume.
- If CO content is less than 0.3% by volume, eliminate leak in area of CO tap tube or adaptor.
- If CO content is more than 1.2% by volume, eliminate leak in exhaust system between engine and HO2S.
- Install a NEW plastic plug over CO adjusting screw. Press on the cap.
- Check idle speed. Idle RPM must be within specification. See IDLE SPEED & CO LEVEL SPECIFICATIONS table. If idle speed is not within specification, check air intake system for leaks. Idle speed is electronically controlled and is not adjustable. IDLE SPEED & CO LEVEL SPECIFICATIONS Application Idle RPM CO Level Checking Value 720-860 0.3-1.2%
- If necessary, check differential pressure regulator current with oxygen sensor connected. Reading must fluctuate between -4 and 6 mA and CO level must be 0.3-1.2%.
Note. If idle speed drops severely when A/C system is turned on, check idle stabilization system.
CLOSED THROTTLE POSITION SWITCH (CTP)
- Remove noise dampener and disconnect harness connector from TP assembly. Using DVOM, measure resistance between terminals No. 4 and 6. (Scheme 3) Resistance must be zero ohms. Operate TP slightly. Resistance must be infinite. If specified resistance is not obtained or is obtained only after opening TP further, adjust CTP switch.
- Remove throttle body assembly. Loosen both potentiometer screws. Turn potentiometer counterclockwise until stop is reached. Ensure linkage is not moved. Tighten potentiometer screws in this position. Install throttle body and adjust cable. (Scheme 4)
- Check CTP again. If specified resistance value is still not obtained, replace throttle position potentiometer.
Scheme 3
Scheme 4
KICKDOWN SWITCH
- Remove noise damper. Disconnect kickdown switch 2-pin harness connector. Using jumpers and a DVOM, measure resistance between terminals No. 1 and 2 of kickdown switch harness connector. Resistance must be infinite.
- Slowly depress accelerator pedal. Kickdown switch resistance must go to "0" ohms in range "A" and "B". (Scheme 5) If continuity does not occur, loosen kickdown switch mounting bolts and move throttle lever by hand to full throttle stop. (Scheme 6)and (Scheme 7).
- Adjust kickdown switch so that switch lever contacts throttle cam. (Scheme 6)and (Scheme 7). Apply locking compound to mounting bolts and tighten.
Scheme 5
Scheme 6
Scheme 7
RPM SENSOR BRACKET
- Remove Crankshaft Position sensor (CKP). Position crankshaft at TDC. (Scheme 8) Screw Crankshaft Positioner (V.A.G. 3242) into sensor hole. Hole in crankshaft can be seen or felt through sensor hole in block. (Scheme 9)and (Scheme 10).
- Remove heat shield. Remove Engine Speed (RPM) sensor and loosen RPM sensor bracket.
- Insert RPM Sensor Gauge (V.A.G. 3308) until locked into gear tooth. Push bracket within slots to ensure sensor gauge is locked into gear tooth. Retighten bracket and reinstall RPM sensor.
Scheme 8
Scheme 9
Scheme 10
THROTTLE CABLE
| CAUTION: | Throttle cable is easily kinked and must be handled carefully during adjustment or installation. A slight kink can lead to cable fracture while vehicle is being driven. Throttle cables which are kinked should be discarded. |
When installing a throttle cable, ensure it is aligned properly between its supports and fixing points. The throttle cable is fixed to the accelerator pedal and the cam disc. Longitudinal adjustment of the throttle cable sleeve is not fixed by the securing clip.
- Fully depress accelerator pedal. Pull back throttle cable sleeve until throttle valve lever rests on the full load stop. See "A" in (Scheme 11). Secure longitudinal adjustment using the securing clip. See "B" in (Scheme 11).
- Depress accelerator pedal fully. Throttle valve lever must rest on the full load stop. Release accelerator pedal completely. Throttle lever must come to rest at idle stop. (Scheme 12) Repeat adjustment if conditions are not all met.
