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Forum namePerformance/Engine
Topic subjectSmoking Idle, compression numbers
Topic URLhttps://forums.2gnt.com/dcboard.php?az=show_topic&forum=i5&topic_id=106944
106944, Smoking Idle, compression numbers
Posted by ThePerfectShift, Nov-25-07 07:16 AM
I just did a compression test, because my car has been running like crap. it will smoke at idle after a few minutes, i'm getting horible milage and it has lost a good bit of power. I've done O2 sensor, new plugs and wires. Plugs looked pretty white though and they have only been in for a month and a half. anyway my numbers are

1---185
2---200
3---190
4---220

I then added some oil in and got

1---250
2---off gauge
3---270
4---off gauge

So, I'm not completley sure whats going on. Any help is greatly appreciated.
106945, RE: Smoking Idle, compression numbers
Posted by WickedESi, Nov-25-07 10:57 AM
Those first numbers arn't too bad individually, but they are kind of all over the place.

Did you warm the engine to operating temp, disable fuel injection, let cool some (don't pull hot plugs out of a aluminum cylinder head), pull ALL FOUR plugs, crank with the gauge hooked up 6 times each cylinder, holding the throttle at wide open?

^ the PROPER way to do a compression test.

...if not redo it, post new numbers.

If you did it correctly, have you changed your oil as recommended?
Clogged oil control rings can leak oil into the combustion chamber while still having normal compression readings.

A faulty PCV valve can prevent proper breathing and cause oil to burn, and oil leaks.

In all reality the problem you are having is most likely worn out valve stem seals.

Those wet compression test numbers are... well hopefully you didn't hydro lock the motor. You should barely put in a cap full of oil, you were putting in too much, which caused those numbers to skyrocket because "fluids don't compress".
106952, RE: Smoking Idle, compression numbers
Posted by RoninEclipse2G, Nov-26-07 04:39 AM
Originally posted by WickedESi
In all reality the problem you are having is most likely worn out valve stem seals. Those wet compression test numbers are... well hopefully you didn't hydro lock the motor. You should barely put in a cap full of oil, you were putting in too much, which caused those numbers to skyrocket because "fluids don't compress".

+1

were you shooting oil out the spark tubes when cranking the engine?