Rough Idle, No Compression on Cylinder 2

[rlpete]

I was driving my 94LX to work last week and it suddenly started idling rough. When I started in the car was running running fine, after about 15 miles of driving I came to a stoplight and noticed a rough idle. I drove the rest of the way to work and made it back home fine. Since it was time for a tune up anyway I changed the plugs, distributor cap and rotor. I noticed some oil in the spark plug wells so I went ahead and replaced the valve cover gaskets and the spark plug rings. When I started it back up it ran just as bad. Next I pulled the spark plugs and did a compression test. 150 psi in cylinders 1, 3, and 4 and 15 psi in cylinder 2. Shot some oil in the cylinders, no change.

A little background, it is a D15B7 engine. I have owned it for 6 months, about 4k miles. But I bought it from my brother who had owned it for 10 years and about 50k miles. It has not overheated or broken a timing belt, there is no water in the oil. All of the posts I have read on this tend to deal with overheating or a broken timing belt, so if anyone has addressed this please let me know.

I also find it interesting that this same scenario happened with my 88 CRX with a D15B6 motor. Didn't overheat or break a belt and lost compression is cylinder 2. If anyone knows of a systematic problem with this please let me know, and is there anything I can try short of pulling the head.

Thanks,

 

[xxBLOOD88SHOTxx]

Broken ring most likely. If you bent a valve you would know it, but a leakdown test is the next thing to do if you don't want to pull the head off.

 

[rlpete]

Got a chance to do a leak down test and the cylinder will not hold any pressure. Did notice the air was escaping out the exhaust so it would appear to be an exhaust valve problem. You made the comment that if it was a bent valve I would know it, all I notice is a bad miss at idle and lack of power. What else could the problem be? any help is appreciated.

 

[xxBLOOD88SHOTxx]

If it bent bad enough it would smack the piston and destroy itself and the piston. It probably has done that to some extent already, maybe even a burnt valve. Pull the head and go from there. Leakdown points to exhaust valve, look there first.