View Full Version : Please HELP!!!! Popping Noise from Eng.

06-23-2002, 06:40 AM
Hey Guys,
My 94 Auto makes a Popping noise "Like A Leakey EXH Manifold or something" under medium to heavy load...If I cycle the Throttle while it is doing it under heavy exceleration it will fade away to nothing....It has me stumped..I thought I had a big vacume line disconnected or something...Heck I don't know...

I took a close look of the underside and found this rubber flap that covers a hole in front of the auto tranny....It was kinda sideways and sh!it so I secured it, but the noise is still there....Not everytime though..Intermitten sound...

Thanks guys,


06-23-2002, 01:05 PM
Does it sound like there are a bunch of little elves in your engine with tiny hammers????

If so that could be pre-ignition that you are experiencing.

The exhasut manifolds on our cars do not use gaskets (at least that is what everyone here says) maybe there was a leak. But since you say that the noise goes away with you change throttle position, that would have me suspect pre-ignition.

06-23-2002, 11:27 PM
Sounds like a stuck bypass valve or detonation to me.
The bypass valve is easy to fix with some WD40 but if its detonation, its harder to track down. Have you put in some low octane fuel, try higher octane. Do you have you had your intake apart and do you have EGR? Maybe the hose is cracked. How is your coolant level?

06-23-2002, 11:59 PM
I had a knocking sound coming from my engine that would only do it when there was very little load on the engine. Like right between 1-2 shift. Turned out to be a splinter stuck in a lifter allowing the lifter to bleed down faster.


06-24-2002, 01:11 AM
For starters,
I mentioned that the popping sound sounded like a EXH. manifold leak so you all could relate to what I am hearing...I know for sure that it is not an EXH Man leak...

Second, I wouldhave to rule out the octane of my fuel since I have heard that knocking sound before, and this is not even close...It is loud, and it sounds like a leak...Compressed air popping sound...It fades as well....Also, it does not happen everytime, but only every once in awhile...If you stab the throttle half or full there is a good chance it will do it...But if you ease it, it is always fine...I recently had detonation with my 90 SC and it is nothing like that either...Where that makes your boost gauge plumet, this does nothing to the gauges, and very little to the performance...

THanks for all of the input, I hope my second response triigers more ideas...THanks much gents..