Heard back fire this morning.....

[rush91]

So, I'm getting out my Beast for a week to drive to work. I let her warm up as I wiped her down a little....When I swear I could hear an exhaust leak coming from around the back of the manifolds or resonator. When driving to work, I got on it a little in 1ST gear, and after shifting to 2ND, I heard a faint pop. It sounded like it came from behind me. Like a muffler.......It only happens between shifts.
My car is 100% stock, and I still have the 1-4 skip shift. I'm really holding off on any type of aftermarket setup, I LOVE the sound of the original exhaust. I know I'm robbing myself of some horses as well. But I would like to find out the cause of the faint backfire. I will try to upload a video.....

[A26B]

You may have an injector leaking. Waste spark ignition fires on 2 cylinders at same time. The paired cylinder receiving the "wastespark" may be getting fuel & igniting on the exhaust stroke.

If the injectors are the originals, this is more likely to be the cause.

I would suggest a static key-on, engine-off fuel pressure test. Observe the pressure bleed down after you turn the key off. A leaking injector will be indicated with a fast bleed-down.

[rush91]

You may have an injector leaking. Waste spark ignition fires on 2 cylinders at same time. The paired cylinder receiving the "wastespark" may be getting fuel & igniting on the exhaust stroke.

If the injectors are the originals, this is more likely to be the cause.

I would suggest a static key-on, engine-off fuel pressure test. Observe the pressure bleed down after you turn the key off. A leaking injector will be indicated with a fast bleed-down.

The injectors were replaced by previous owner by Marc Haibeck. He changed them twice, last time with injectors off of a 1994 Z. It runs flawless, doesn't miss or hesitate at any RPM.... It seems to happen when the engine is not up to temp. Once warmed up I don't notice. Sounds like the right side manifold maybe, then I hear faint backfire on right side muffler. Only seems to happen on 1st to 2nd shift under acceleration, and it very faint.... I will see about getting a pressure test. A good set of test manifolds would be a great purchase for me lol thanks

[Paul Workman]

So, I'm getting out my Beast for a week to drive to work. I let her warm up as I wiped her down a little....When I swear I could hear an exhaust leak coming from around the back of the manifolds or resonator. When driving to work, I got on it a little in 1ST gear, and after shifting to 2ND, I heard a faint pop. It sounded like it came from behind me. Like a muffler.......It only happens between shifts.
My car is 100% stock, and I still have the 1-4 skip shift. I'm really holding off on any type of aftermarket setup, I LOVE the sound of the original exhaust. I know I'm robbing myself of some horses as well. But I would like to find out the cause of the faint backfire. I will try to upload a video.....

An exhaust leak can contribute to "popping" too.

I have a 90 w/ SW headers and I sometimes get a bit of popping on decel - once in a while. It started after I took my Z "flying" a couple years ago.

I noticed a trace of soot at one of the clamp joints between pipe sections. I'm hoping that if I ever get around to welding it that it goes away for good.

[rush91]

An exhaust leak can contribute to "popping" too.

I have a 90 w/ SW headers and I sometimes get a bit of popping on decel - once in a while. It started after I took my Z "flying" a couple years ago.

I noticed a trace of soot at one of the clamp joints between pipe sections. I'm hoping that if I ever get around to welding it that it goes away for good.


I really need to get under the car, and check out all the welds. The exhaust tips, have always been sooty since I've owned the car. The car doesn't smoke at all, and I don't smell any exhaust smell ever.

But it is a beautiful day here, got the top off, and ready to give the Beast a good flogging on the drive home. Hopefully that's just all she needs.

[BigJohn]

Yah, I had that same problem the other day; everyone stayed away from me!