How to do a compression test?

[Turbo Goose]

Hi guys im going to view a starlet today and I want to do a compression test on it. Ive purchased a compression tester.

Do I need to disconnect the fuel pump/ fuse. Do I need to tske all plugs out or just plug leads? Do I press throttle down? Do I do it hot or cold?

Ive been told different things by different people

Thanks guys

Dan

[Gainzy]

Start it up for a little if you feel as though you trust the car just do one cylinder after a drive... yes take the fuse out I would take some body with you as they can turn the key put the pedal to the floor whilst you check the gauge or if you decide to do all 4 cylinders you can check the condition of sparkies

[Gainzy]

Also diconnect the king lead!

[5T4R7ET N/A]

Do test with warm engine, and take out the efi fuse in the fusebox that's in the engine bay.

Remove one (so you remember what lead goes where) spark plug and make sure you put the tester in properly, not too tight can be hard to get off.

When cranking the engine do it with throttle pedal pressed to the floor the whole duration of cranking. Cranking for around 10 seconds is plenty, the compression gauge should be around 10-12 bar and it won't go any higher anyway after its reached max pressure.

Write down reading and release pressure in tester, should be a button to do this. Put plug and lead back in and do the same to next spark plug

Edited February 23, 2014 by 5T4R7ET N/A

[Chops]

i count the number of cranks to try and keep the test as even as possible. about 8 cranks should get your pistons maximum pressure.

[AdamB]

Warm engine, disconnect one plug at a time, disconnect the EFI fuse and pull the plug from the ignitor/coil, crank engine with wide open throttle for no more than 10 seconds or until the gauge has reached equilibrium