hopefulfan_dc Posted May 22, 2005 Report Share Posted May 22, 2005 I wanna know, in general, how to do a compression check...help Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted May 22, 2005 Report Share Posted May 22, 2005 you want to do it with the engine at operating temperature. first pull ALL the spark plugs out. then disconnect the CPS from the ICM so the injectors don't fire while you're doing the test. screw the compression tester into the spark plug hole and monitor the gauge while a friend cranks the engine over. monitor how fast pressure builds up (should peak after 4-5 engine rotations). take notes of each cylinder and compare them to each other. each cylinder should be within 10% of each other. Quote Link to comment Share on other sites More sharing options...
89GPSE Posted May 22, 2005 Report Share Posted May 22, 2005 correct. done Quote Link to comment Share on other sites More sharing options...
Jcrow Posted May 23, 2005 Report Share Posted May 23, 2005 When I did mine, all the cylinders had 150 psi +/- 3psi Just to give you an idea of what to look for Quote Link to comment Share on other sites More sharing options...
joey b Posted May 23, 2005 Report Share Posted May 23, 2005 am I getting this right? At operating temperature you are supposed to pull the spark plugs? :? Quote Link to comment Share on other sites More sharing options...
mihela816 Posted May 23, 2005 Report Share Posted May 23, 2005 Yeah that seems like you're asking to strip the holes. I know why the engine needs to be at op temp, clearances and thermal expansion... but is there any safer way to do it? Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted May 23, 2005 Report Share Posted May 23, 2005 to check compression...yes. check compression at operating temperature....that means pulling the plugs with the engine warm. there really isn't any way around it. i've done it many times even just to check plugs and i've never had a spark plug blow out or strip a hole (????). i know there is an underhood sticker that says you shouldn't, but i've never had any issues. Quote Link to comment Share on other sites More sharing options...
JoroCorona Posted May 23, 2005 Report Share Posted May 23, 2005 If you go slowly on the plugs you should have no problem with the plug stripping the head. I pull plugs out of hot hondas without stripping them, and they are notorious for stripping. Just gotta be careful. Quote Link to comment Share on other sites More sharing options...
Jcrow Posted May 23, 2005 Report Share Posted May 23, 2005 I did mine cold Quote Link to comment Share on other sites More sharing options...
cutlsp Posted May 23, 2005 Report Share Posted May 23, 2005 I did mine cold i don't think its very good for the aluminum heads to do a check with the motor hot. i'm going to be doing mine cold also this week. Quote Link to comment Share on other sites More sharing options...
Guest TurboSedan Posted May 24, 2005 Report Share Posted May 24, 2005 will your rings be sealing 100% when cold? or the valve seals for that matter. Quote Link to comment Share on other sites More sharing options...
19Cutlass94 Posted May 24, 2005 Report Share Posted May 24, 2005 pulling the spark plugs out when the engin is warm is a bit sketchy but its the only way to do it, well to do it the right way anyways Quote Link to comment Share on other sites More sharing options...
joey b Posted May 24, 2005 Report Share Posted May 24, 2005 I would probably loosen the spark plugs while cold, retighten, get to temp, then remove. Quote Link to comment Share on other sites More sharing options...
Jcrow Posted May 24, 2005 Report Share Posted May 24, 2005 My friend has a 3100 and changed his sparkplugs the other weekend while the engine was hot, now the front middle plug is real sketchy, we were afraid to tighten it all the way because it seemed like it just kept spinning. It runs and the plug stays in but I wouldnt want to have to rip the heads off for a stripped spark plug Quote Link to comment Share on other sites More sharing options...
hopefulfan_dc Posted May 27, 2005 Author Report Share Posted May 27, 2005 Thanx...I will safely do my test...while the engine is WARM....and like any fastener in AL, slow and easy.... very helpful Quote Link to comment Share on other sites More sharing options...
Canada Posted May 28, 2005 Report Share Posted May 28, 2005 Do it while the engine is warm......not HOT. There is a difference there.... Quote Link to comment Share on other sites More sharing options...
Redwingvksm Posted May 28, 2005 Report Share Posted May 28, 2005 Meh. I say cold. All the cylinders should still read around 10% of each other... These are aluminum heads - I (as a mechanic) - would NOT take the chance on my own car - as well as someone else's. It shouldn't matter that much if it's cold - what a 20 PSI drop tops? As long as they are all relative to eachother you should be ok... :shock: Quote Link to comment Share on other sites More sharing options...
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