popping sound in engine

gdixon · 11-26-2003, 11:15 AM

I have a 99 4.0 that is making a popping sound in the engine whenever it has a load on it (i.e., accelerating, too high gear, etc.). It sounds like an exhaust leak, but I can find no leaks and I have the full Banks exhaust system. the sound seems to be coming from the top of the engine near the rear of the block. The sound is annoying, but it has not produced any noticeable effects on engine performance. Any suggestions as to what this might be?

thanks

Bachman · 11-26-2003, 08:52 PM

It kind of sounds like it may be preignition detonation. Try running a high octane gas. That might solve the problem..

xxxflhrci · 11-26-2003, 08:58 PM

It shouldn't need premium fuel to prevent pinging. I don't think your engine call for premium. Check your owner's manual.

Your pinging is probably a timing issue. Retarding your timing a few degrees should solve the problem.

Premium gas in an engine that doesn't need it is a waste of money. You won't get better mileage, more power or make your engine last longer.

**thephantum** · 11-26-2003, 09:09 PM

Ya, you should not need premuim fuel. The 4.0 is designed to run on 87 or 89 octane. Using higher octane might mask the symptoms, but the problem will still exist.

You might have a bad sensor (O2, TPS, etc) somewhere sending erronous signals and causing the computer to set the wrong timing curve.

How many miles have you got on it? You might also just have some carbon buildup causing the detonation.

Good Luck!

Rock On!

Steve

**doorocks** · 11-27-2003, 06:05 PM

Quote:

Originally Posted by gdixon

I have a 99 4.0 that is making a popping sound in the engine whenever it has a load on it (i.e., accelerating, too high gear, etc.). It sounds like an exhaust leak, but I can find no leaks and I have the full Banks exhaust system. the sound seems to be coming from the top of the engine near the rear of the block. The sound is annoying, but it has not produced any noticeable effects on engine performance. Any suggestions as to what this might be?

thanks

From my past experience, it could very well be the seal on a fuel injector. Injectors pulse when sending fuel, they don't spray continuously. It's fairly high PSI, in a confined area with no way to escape but through the easiest route......a bad ring. Very easy to check and fix. But if you've never removed a fuel rail before, have someone help you that has or buy a FSM for the step by step. The injectors HAVE to be pulled straight out and seated in the same fashion or it will not seat correctly in the rail itself, causing a nasty fuel leak. The ring kit is about 12.00.

Ask me how I know.

Let us know what the solution finally is for our data banks.