Exahust backfire thingy out of a Z24

[Nissan_Boy85]

Ok guys, my Z24 is "popping" out the exahust. It kinda sounds like a half-ass backfire attempt. It's timed correct with new timing chain and guides. Any and all help is appricated as always. If you live around here and wanna hear it, just give me a holler. Thanks!

[Skib]

hows your air/fuel?

[jesusno2]

My 720 does the same though ever so slightly. It may be a slight exhaust leak cause I couldn't get all the way around the pipe in one spot when I welded it up. Or could be a burt exhaust valve?? But my truck runs so good I just leave it be. I barley notice it anyways yours could be the same possibly ??

[Nissan_Boy85]

I'll look at that Skib. Would that indicate it's too rich or too lean?

 

It's not an exahust leak, but my rear hanger is broken and the cat is bad, but thats a different problem. And if you call barely noticeable hearing it over my radio with the windows up, then yes. ;)

[jesusno2]

Mine is just at a idle is yours at idle or driving?? A lot of rigs backfire when letting off the gas especially under a load, Like coasting down hill which is caused by exhaust leaks or to lean air fuel mixture.

[Nissan_Boy85]

It's when I'm using the engine to slow me down. I've gotten it to go away on my old motor, it just that this one is being a bitch about it.

[datzenmike]

If the emissions hasn't been modified there is a fuel shut off system on deceleration using the idle cut solenoid. This removes the idle mixture which isn't needed on deceleration and returns it if in neutral or if the clutch is depressed. If it isn't working this might be what you are hearing.

Edited November 17, 2008 by datzenmike

[Nissan_Boy85]

One more thing to check Tuesday. Anyone up for a tech night? :lol:

[datzenmike]

Check the EGR tube from the exhaust up behind the head. They can rot out and leak. Check the down pipe gasket for leaks.

[Nissan_Boy85]

Would not having a PCV valve be a cause helping the problem along?

Edited November 17, 2008 by Nissan_Boy85
BECAUSE I CAN!!!!

[agentalpha]

It is fairly normal.

What is happening is when the throttle closes, the engine goes lean.

Ever play GTA, and the exotics pop outta the exhaust when you shift?

That's what they are modeling.

 

Check for exhaust leaks.

ANY, no matter how small, will aggravate it.

The leak will add oxygen to the flame.

Edited November 17, 2008 by agentalpha

[kiznook]

what kind of exhaust do you have?

 

My 91 (KA) did the same thing with my old exhaust, but is fine now that I'm back to stock

[Nissan_Boy85]

Not sure due to the fact it came with the truck. I should look at it today. It looks like it has a pacesetter header, shit cat, and unknown muffler. Will look at it today. Thinkin about going back to the stock manifold.

[datzenmike]

Would not having a PCV valve be a cause helping the problem along?

 

Not very likely but you should connect it up and use it. Good for the motor, has no effect on running. The PCV valve is on the valve cover side and at the base of the carb and screwed into the intake, There is a small rubber hose with a 90 degree bend that you can just barely see.