Engine Popping

[Like2Play]

Here's what it's doing. At idle, it sounds like a plug is missing, like it's blowing air. When I rev it, it turns to a popping sound that increases as the rpms increase. I've felt around trying to feel airflow, and tried to give it a good listen, but all I can say for sure is it's on the back side (of course) of the motor. Any ideas?? TIA.

[jheiv]

I had carbon buildup on an intake valve that siezed it up... this was the result of a plug wire open... don't know if this will help but try a compression test... post your results... and remember to squirt oil in the plug hole after you find low compression... see if you get any improvement.

 

-jheiv

[maddux31]

what kind of car/engine? And what do you mean by popping?? My motor (3.1 turbo) made a popping sound when I had a cam lobe blow off. Could be something with a valve like mentioned above. Give some more details on your car and the symptoms. You can also try a mechanics stethoscope to isolate the noise. If its a cam lobe the noise will be extremely loud with pre-throttle body intake hoses/piping removed.

[rudefyet]

if it's loud pinging like noise

 

you might want to check the psi if it's a turbo

 

or check the compression i assume for N/A

 

cause that's a sign of detenation...that can destroy your pistions

[Like2Play]

Sorry for being so vague. I have a 96 GP SE with a 3.1. I started doing a compression test tonight to verify suspicions. I got 2 and 4 done, with 150 psi. I was thinking cool, this will work, then I got to 6, which had 150, but would leak down fairly quickly (5-6 seconds). This isn't good. I did 1, and it leaked down as well, and when I got to 3, I couldn't get 90 psi out of it. No need to do 5, since when I was underneath of it, I finally saw evidence of blowby. Further investigations tonight confirmed suspicions of a bad head gasket on the back bank. I had a feeling, but could never get to feeling around in the right spot. At least now I know what to do.

Thanks to everyone..

[maddux31]

If you need any advice on the head gasket when you start the job (if you do it yourself), PM me on the board here. Unfortunately I've had a good amount of experience with the heads off and on as of late. If you are fairly mechanically inclined the job is not that difficult. Dale.

[Like2Play]

Thanks, I'll pm you if I get stuck. I wish I would have found this board when I was rebuilding the 3.1 for my Lumina. Would have made things a lot easier, I'm sure.

[Like2Play]

Finally got it started,, got the intake off last night, the only things left are the exhaust manifolds and the heads themselves. What a PITA this is. :?

[Like2Play]

Finished the head gasket, it wasn't bad, just a lot of stuff to take off. Here's the culprit. Now that the car is fixed, I can sell it.