MK2 Turbo-Compression test.

[RENOFOXX]

just performed compression test - results in psi were 175-165-160-160-
is this ok?

[RobCrezz]

just performed compression test - results in psi were 175-165-160-160-
is this ok?

I dont know much about this, but from what I have heard that is ok. Its only if there is really big differences IIRC.

[toxo]

That's fine, mine were similar. Slightly stronger towards one end of the engine but not by a large enough margin to worry about. If one of them were dipping round to 130ish while the others were around 160 then that would be a cause for concern.

[Marf]

Thats taken from the ST205 workshop manual, should be the same for rev3+ cars.

[RENOFOXX]

thankyou all for your replies,thats put my mind at rest.

[MR2 Rich]

Does it matter if you do a compression test when the engine is cold or hot?

[toxo]

Supposed to do it hot

[MR2 Rich]

Have been reading about it and it does seem to be 50/50 on the info I've found, Peter said do it when it is cold, I'm confused.. Which doesn't take much

[toxo]

In the part of the engine manual that Marf posted step 8 from, step 1 is 'warm up engine to normal operating temperature'.

http://bgbonline.celicatech.com/94_205_ ... G/EG36.htm

[MR2 Rich]

We are alway being told to use the search function so when I found this I thought I may as well post on this thread.

So the process is;

Remove EFI fuse.
Take out all spark plugs.
Connect pressure tester to one cylinder.
Accelerator to the floor.
Crank for 5 seconds?
Record results.
Move onto next cylinder and so on.

And either cry or leap for joy...

[Marf]

Yep.

[MR2 Rich]

Thanks Marf

[MR2 Rich]

Well I did the test last night.

I removed the spark plugs and the one nearest the cambelt was absolutely knackered, really black with the electrode bent back. Was a bit shocked since they have only done around 1000 miles.

So was expecting that compression figure to be low and....it was the highest one.

From left to right I got; 197,195,165,201.

So I put a little bit of oil down number 3 and it jumped to 200, any ideas?

[toxo]

As per diagram above, if oil helps then worn rings or cylinder bore.

All those numbers are high though!

[MR2 Rich]

I know they are meant to be uniform but 165 isn't low as you say. I just don't understand this car, it runs soooo well 99% of the time, get the odd bit of smoke out the back under very heavy acceleration but none at any other time but it is using oil. The spark plug next to the cambelt was absolutely knackered but the night before I accelerated very hard and it pulled so well in each gear without any hesitation. Have had an emissions test this week and it isn't burning oil on idle or at 2000rpm 3000rpm or 4000rpm, don't know under load but don't see any out the exhaust except as I've said under very hard acceleration.

Think it's going to Petes and see what he finds with a leak down test and maybe rocker cover off.