How to do compression test

Nov 2, 2004
9,335
0
South Wales
This is what i used.

1. Release locking pins for engine cover by turning 90 degrees. Remove the cover completely.

2. Warm up engine until it is a minimum of 30 degrees Celsius (60 degrees F) and switch ignition off. Get it up to driving temp as a cold compression test is next to useless.

3. Disconnect 4 pin harness connectors from all ignition coils and
remove ignition coils (Place them in a way that you know which ones are for each cylinder). If you have an AWD engine code unbolt the coils from the head and remove the vacuum reservoir (canister).. If you have an AWW or AWP engine code just remove the coils.

4. Use compressed air to clear area around spark plugs. Remove all spark plugs and lay aside in an order that you remember which one goes to each cylinder.

5. Remove fuse #32 for voltage supply to injectors (in car) - i just disconnected the injectors but check what fuse is needed.

6. Fit compression tester into spark plug hole.

7. Have a helper - Depress clutch pedal fully, Put transmission in either park or neutral, Depress the accelerator pedal to floor, Crank engine over with starter motor. Crank a minimum of 4 to 5 revolutions.

8. Record readings from each cylinder in gauge and repeat procedure for each cylinder.

9. Compare readings to these specifications. New Cylinders (145-203 psi) Wear limit (102 psi) Maximum difference between cylinders 44 psi

10. When all cylinders have been checked, reinstall spark plugs and ignition coils, connect harness connectors for coils and reinstall fuse #32. Reinstall fuse panel.

NOTES Cranking engine with ignition system disabled and components disconnected will cause Diagnostic trouble codes (DTC's) to be stored in engine management system memory. You must clear these codes.

Tightening Torques Spark plug to cylinder head - 22 ft/lbs

Tightening Torques Ignition coil to cylinder head (If bolt down coils) - 7 ft/lbs.
 
Last edited:

Big_daddy

Going going gone.....
Oct 20, 2006
3,930
0
Brummy
Cheers Phill, question for number 3. Do you just disconnect each coil pack and remove it from each cylinder? is that all regarding ignition side? (dont want get shocked .lol )
 

emlyn11

Active Member
Oct 28, 2008
358
0
Surrey
Yeah just disconnect them mate it's only HT where the coilpack meets the plug,
so if its unplugged from the loom you wouldn't get shocked.

Emlyn
 

Big_daddy

Going going gone.....
Oct 20, 2006
3,930
0
Brummy
Fuse 32 relates to central locking car still started with fuse out, just un plugged the injectors instead.
 
Progressive Parts, performance parts and tuning specialists