Uneven compression

Sep 07, 2003 4 Replies

Hi all...



I have a 1994 pickup with a 22RE with 85,000 miles on it.



I did a compession check and 3 cylinders showed about 180 PSI, and 1 showed about 145. I added some oil the the weak one, and it also got up to about 180 (so I guess its the rings--I do have a valve that taps, but it seems to come from a different cylinder). All of them took 3 or 4 compression stokes to get up to maximum pressure.



The manual says they should be 171 with a minimum of 128. However, I've also read many places that they should all be with 10% of each other.



The engine seems to run fine. It's very smooth, seems to have good power, and, other than a little valve tap, sounds fine. The truck doesn't burn any oil.



Should I be worried about the difference in the compression in the one cylinder?



Thanks.



Stan


I would let it alone. Just for fun check the pressure of each cylinder with the engine running and you will likely fine the readings are lower but about the same for each cylinder.

I'd also leave it alone if it runs well and no other problems that seem related. On my '88 my oil consumption went down after I started using

25% synthetic oil. I'm assuming that it may have freed up a stuck ring or something. Which might also be the case for you. Recently bought a '94 with 108k ... love it!

Why not adjust the valves and see if that helps?

Search the internet. Some people have tried pouring ATF fluid into the cylinder, and let it sit for several hours to free up the piston rings. My compression went up after doing that.

Ben

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