Did a cold compression test on a 2.5 liter. (it won't start) and all cylinders are almost exactly the same, 60lbs. This seems low to me. anyone know what it should be?

Still trying to get the motor running after pulling it from a 93 wrangler and putting it into a 87 cherokee.

Thanks.

 

155-185 psi from Haynes manual.

 

Min of 90 for combustion to occur.

 

thanks for the help, that might explain the no fire..

 

You don't need compression to have spark. Is a no spark situation your problem or low compression?

 

cylinders washed out with gas can give you low compression, so if you've cranked the crap out of it, flooded it, or injectors are stuck that could be a part of it. granted all 4 injectors stuck open is almost impossible.

time for a cylinder leak down test.

 

Good Idea dave.

 

gas wash down is a definite possibility. it has a single tbi injector that was just gushing fuel when we began to try and start it. we replaced the injector with a new one, but had already flooded the motor pretty good. we were going to squirt some light oil into each cylinder to try to bring the comporession up. any other ideas?

This site is amazing, thanks to all who are trying to help!

Scott

 

Just let it set for a day or two the oil trick works but it also forces the compression so high that you can't get a real true reading. JMHO.

 

also change the oil right away, let it sit with the spark plugs out will help also, blow compressed air into the cylinders if you like. i didn't realize it had the tbi, hopefully thats all it is.

let us know.

 

What ever came of this thread? How's your Jeep? What was the problem? I'm having similar issues right now.

 

bringing a thread from the dead? Guy only posted 6 times and joined in 2008. lol

 

I'm trying to solve a similar problem and hoped he was still around.