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Old 27-08-2011   #1
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compression?

i did a compression today and i was getting 2bar (25psi) on all cylinders. Is there a correct pressure? thanks
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Old 27-08-2011   #2
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Re: compression?

Hi
I've had a look through my haynes manual and can't find a recommended pressure for the compression test but it does say "all cylinders should produce very similar pressures; any excessive difference indicates the existence of a fault"
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Old 27-08-2011   #3
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Re: compression?

Something is wrong, but more probably in the way you did it. You should do it with the throttle fully open, engine up to temperature, and the TDC sensor disconnected.
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Old 27-08-2011   #4
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Re: compression?

Should be up around 160psi.
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Old 27-08-2011   #5
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Re: compression?

i have tryed it with the throttle open and its around 50psi now? where is the TDC sensor? am i doing it right with taking all the plugs out? Thanks
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Old 27-08-2011   #6
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Re: compression?

You are cranking it over for atleast 5 seconds aren't you?

Thanks

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Old 27-08-2011   #7
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Re: compression?

It does seem very low. Follow the lead from the TDC sensor back upwards -- there's usually a connector on the plate below the TB.

Can you let us know why you're doing a compression test?

This is a good guide.
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Last edited by fingers99; 27-08-2011 at 18:01.
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Old 27-08-2011   #8
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Re: compression?

Quote Originally Posted by fingers99 View Post
It does seem very low. Follow the lead from the TDC sensor back upwards -- there's usually a connector on the plate below the TB.

Can you let us know why you're doing a compression test?

This is a good guide.
why im doing it is because the headgasket went but we never got the head skimmed when we fixing it and there is still a little bit of white smoke still coming out of the exhaust on start up and idles high on start up but then goes normal Thanks
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Old 27-08-2011   #9
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Re: compression?

Puzzling. Usually the HG will go between 2 cylinders, rather than all 4!

I'd be inclined to crank it for at least 10 seconds, leave all the plugs in apart from the one with the guage in.

But something is wrong with the readings -- if the compression as really 2 bar I'd not expect the engine to run.
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