[mrayner]

I am going to do a compression test. I have never done one before. It seems to be quite strait forward, but hey I am a newbie so I have a few questions for those that have done this on a 968.



I know that I should bring the car up to temperature before the test. Also that I should remove all 4 plugs, disable the ignition. I have a compression tester.



1) How many revolutions. 4?



2) The workshop manual recomends that the rpm sensor is disconnected before conducting a compression test. It says it may become damaged by the procedure. Where is this sensor located and how should I disconnect it?



3) What is the correct way to disable the ignition system. Simply remove the plug wires and the conection from the coil to the distributor? I want to be safe.



4) Opening the throttle....? Or get a friend to step on the gas? What is the correct procedure here.



Any other advice for a safe and acurate test?





Thanks everyone!

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[orphanowner]

Pull the DME relay to disable the ignition and prevent fuel from flooding the cylinders.



Remove ALL the spark plugs



Wire the throttle wide open or get a friend to help you crank the engine and floor the throttle.



Spin the engine as many revolotions as it takes to get a maximum value. This will be pretty obvious and shouldn't take more 5 seconds of cranking.



Post the results here so we can all comment on your engine's condition.



Total time, 15 mins.



Nothing else needs to be removed, disabled or proceedured.

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[mrayner]

Thanks for the tips orphanowner! I just finished the compression test. Here are my numbers



190-195-190-195



Although higher than most of the numbers I see posted..these are pretty darn good IMO. This is on an engine w/ 74k miles.

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[sasilverbullet]

yep, very good numbers...mine are in the high 180's...

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