Can a broken/jumped timing belt cause NO compression in just one cylinder? The adjacent cylinder has good compression and the engine still runs (but very poorly!)

no, sorry, your screwed=]. either a valve is stuck open, or burnt, or your rings are shot. how many lbs in the other holes?

The right front is zero lbs- didn't even move the needle! The adjacent one (right rear) is 105-110 lbs. I haven't tested the left ones yet.

Do a wet compression test. Put a couple tablespoons of oil into the cyl. and then do the test. if all of a sudden you have compression, may not be to spec but still better then before, then you have bad rings. you may already know this but i thought id chime in just in case.

 

Mike

seldom does a cyl read 0, sounds like your intake valve is stuck open.

i was thinking about this, if you had the belt way off, you might get one to work, and the other one might have the valves wide open at the wrong side. usually you dont get a 0lbs reading unless you have a big hole in your piston, or a valve is stuck.

If the intake valve's stuck open, is there any way to unstick it?

Yea bad compression rings would not read 0. you would just have low compression. But it does sound like the intake is stuck open. Even a burned valve wouldnt read exactly 0.

If stuck valve is truely the issue, a bad valve seat or bad lifter/lash adjuster is likely the culprit.

how many miles on the motor? sludge, carbon, lash adjustment bad valve seat. I think your best bet is to pull the head off and take a look for your self. there most likely isnt going to be a quick engine in car fix for this.

What car are you having trouble with, the 90, 87, or 84?

It's the '87, EA82T, about 125k on the odo. No sign of oil in the coolant or vice-versa so I'm guessing it wasn't the head gasket.

I'm a ea81t & ej22t guy. I never had an ea82t apart. I would ask skip, he seems to know a great deal about ea82t's. Like Archie said, it could be timing, I hate to see you take head off if you don't need to.

that you have a valve stuck open, for what ever reason. Would suggest an air supply plumbed into dead cylinder, then listen at the intake and exhaust. You'll be able to tell very easily what it is, from this test.

i think the head may have dropped a valve seat, as i ahve seen a few examples

 

suppose if you pulled the head, you could have it staked back in? i have read in auto books about staking valve seats

 

so it may be worth it to ask about that to your local machine shops, get their opinions...