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Old 02-13-2012, 09:12 PM   #5 (permalink)
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Lean and Mean - '98 Honda Civic HX
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Originally Posted by Old Mechanic View Post
Before you replace the engine, do a few tests to determine exactly what is going on. Is the compression loss due to a valve problem? If so then you might consider a valve job.
In many cases the lost compression types of failures are due to blocked EGR passages, leaky intake manifold gaskets, or other vacuum leaks that make one cylinder run a lot hotter than others and cause a burned valve.

If you have tested this then ignore my advice, but a squirt of oil in the suspect cylinder and a re test of compression could tell you if the valve is your problem or the pistons-rings.

It's just cheap insurance to try to really pinpoint the problem, as well as understand the other potential causes of what has happened.

Follow a good overall diagnostic procedure, and avoid the possibility of an engine replacement that does not fix the original problem that caused the low compression on one cylinder.

Then you eliminate the risk of damage to the new engine, or damage to the same engine that has been repaired. In either case the bottom line is lower overall cost.

Welcome to the forum.

Ya it kept getting worse and worse. At first I noticed a rough idle. I did the typical tune-up with plugs, wires, cap/rotor, etc. Still ran rough at idle. Then I thought that it was weird that no CEL came on. So it turns out someone removed the CEL bulb. I had a few codes. One was for the EGR valve. Cleaned that out as well as IACV. Took care of that but didnt run better. The other code was a misfire in #2. Cleared the codes and drove to work (50 miles) and the code didnt pop up but it was still running rough. On the last part of my drive there are some stop signs. At idle it started to misfire and threw the code.

At this point im thinking its an injector or something to do with fuel. Swapped out injectors on #2. Still no luck. Finally I did a compression check. 140 psi in #1. 25 psi in #2. Put some oil in #2 and re tested. 45 psi. So now I know the rings and cylinder walls are pretty much shot with that low of compression.
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