How To Carry Out A Compression Test

Steve Wed Jul 16, 2008 10:07 am

1) Buy, beg, steel or borrow a compression tester. The one used here is a Gunson tester.

2) Warm engine to operation temperature

3) Disable the fuel pump and ignition. I did this by pulling fuses 2 and 4 in my 1997 2.0 Sport.

4) Remove plug from dis module

5) Remove HT leads and remove plugs - Carefull they will be hot

6) Install tester into cylinder number 1.

7) Have a good looking assistant (or if you cant find one get some ugly passer by) hold the throttle open and crank the engine.

8 ) Watch the tester. In a healthy engine the tester should leap a large amount on the first compression stroke. Keep cranking until the tester doenst get any higher.

9) Wave / shout at your assistant and tell them to stop cranking.

10) Record result.

11) RESET TESTER

12) Repeat from step 6 for other cylinders.

13) Reinstall plugs, leads, reconnect dis and put fuses back in.

14) Check car starts

15) Job Done.