How to Compression Test... Stupid Question

[Goodguy162000]

This may be a stupid question but I can't find the answer anywhere. Could somebody please give me a walk through and any tips they might have on doing a compression test. I bought the equipment from Autozone ($20) and I'm ready to rock & roll. Thanks in advance...

 

[logic]

This may be a stupid question but I can't find the answer anywhere. Could somebody please give me a walk through and any tips they might have on doing a compression test. I bought the equipment from Autozone ($20) and I'm ready to rock & roll. Thanks in advance...

I was about to respond with "search google for DSM compression test, click on first result", but I'm in a giving mood today. See dsmgrrrl's excellent write-up on performing a compression test: http://www.dsmgrrrl.com/FAQs/compression.htm

 

[boostedinaz]

This may be a stupid question but I can't find the answer anywhere. Could somebody please give me a walk through and any tips they might have on doing a compression test. I bought the equipment from Autozone ($20) and I'm ready to rock & roll. Thanks in advance...

Some people may have a different way but this is what I do.

I get the car up to normal temps then pull a plug and put the tester in. I make sure that the MPI fuse is pulled so the car will crank but not start. Have someone go WOT with the pedal and crank the car for a few seconds. The gauge will jump a few times and stop at a certain reading. If the numbers are good then I leave it at that unless I think there may be a problem. If they aren't I get a bit of oil and drop it down into the cylinder that I am testing and see if the numbers go up. If they do most likely the rings are on there last leg. i wish I knew off the top of my head what the service limit is for our cars, I think it may be about 120 or so, but again not sure.