exhaust backfiring
 

ill drive to where i got to go and it will backfire when i turn the car off. help me fix my problem. please. everybody thinks im shooting at them.

Could be a different number of reasons. If you could give us some more details we might be able to solve your problem.

um i just rebuilt my stock carb cause i had too much gas flooding my engine and it was backfiring. so i rebuilt it. that was fine. it ran better than ever well it still backfires. plugs are clean and wires are good so i dont know what is going on.

hows the mix? lean it out a little bit and see what happens. "everyone thinks i'm shooting at them" LOL!!!!!!!!

im guessing your running your card way to rich

-greg

Mine has an exhaust leak causing it to backfire... I like it!

The 82 I picked up did that until I pulled the emissions and reset the idle/mixture screws. Which one was the cause? I'm betting on both ;)

what is the mixture screw suposed to be set at? how many turns? if i screw it in how many turs out?

Check your exhaust manifold gasket.

umm on most engines ive worked on the main cause of a backfire is the timing being off

i got a header and i know there is no leak there. i want to know how many turns out the mixture screw is suposed to be. thanx though

mixture screw, mine only moves a total of a half turn, qaurter toward rich and a quarter towards lean, and i leave mine in the middle

Jim he is talking about a 12a with a carb, not EFI like your SE.

its a 12a and yes it is carburated, does anybody know how many turns it takes to get it running right so it doesnt backfire. i went to a small town gas station 2 days ago and it backfired, everybody outside fell to the ground cause they thought someone was shooting at them.

I set the "default setting" at 2 1/4 turns from closed.
You should'nt have to move it much more than 1/2 turn either way.

My SE is backfiring also, but at high speed
 

I finally am able to drive my '84 beige SE at real speeds, and I find it is backfiring. It doesn't happen very often, but at high speed (say 60-80). It seems to happen when I back off the accelerator - that is, reduce my rate of acceleration, not my speed.

In 10-15 minutes it happened 3 times, all above 60mph, but it startled me.

To make matters more challenging, I have very little knowledge about the exhaust I have (I just bought the car). It has a RB header that has been shortened. It then connects to a SS pipe with a two foot section in the middle that is about 3" diameter (2" diameter connectors on both ends), smooth at both ends (very professional welding) looks like a 2" diameter snake swallowed a 3" diameter sub sandwich. That bolts to the piece that goes over the axle, and then you have a short muffler (also SS).

So, there are no cats. I am not sure I will be able to pass the Texas safety inspection (non-emissions check county), but I will try tomorrow. I have the complete OEM exhaust, but I don't want to use it unless necessary.

The seller, who knew even less, said he thought it was straight through. He said his buddy saw sparks coming out the back one time at night.

The engine is very strong and responsive, the clutch and tranny are great, and the exhaust is very throaty when accelerating. At idle the exhaust is only slightly noisier than stock. The owner prior to the one I bought it from was trying to put it in a race config, and stripped out **a lot** of things. The EFI is still stock.

Any help identifying the exhaust components or resolving the backfire would be appreciated.

Thanks,
BTC

I had the same problem and I reset the timing on target, rebuilt the carburetor, and finally replaced the main exhaust gasket.

I found the real problem by mistake when I was checking for vacuum leaks around the carburetor. I was spraying carburetor cleaner around the bottom of the air control valve with the car running and I noticed an increased in the car idle. As I sprayed closer to the exhaust manifold the idle increased.

I replaced the exhaust gasket and the backfiring is history.

wow good point. even though my exhaust is relativly new maybe i do got a bad exhaust gasket. good i dea ill try that and the adjustment of the carb is 2 1/4 out. ill try that too. thanx guys. any more input would be awsome.

You may have the wrong exhaust gasket, period, for that matter. Exhaust leak is why the car backfires. You're letting in O2 to mix with unburned HCs in the exhaust area which is still hot enough to initiate ignition...:cool:

Mar 3 is right!! Backfiring on rotarys is usually caused by ignition, running rich, exhaust leak, or vacuum leak. My SE has a huge vacuum leak right now. I broke of one of my ACV bolts when putting on my plate.......She sounds like I have a 9mm under my car:)

All you have is a 9mm?!?! Mine sounds at least like a .45 ACP, and closer to a .50 BMG with 3" barrel!!

;)

5 minutes of driving my car........and I can't hear anything anymore.......so it doesn't bother me. Other people, like cops.......seem to LOVE IT!

My car backfires I have a 85 se. it usually does so when I push the clutch in and let the rpms drop rapidly. I can even get flames out the back if I rev it up and turn the engine off quickly. Although I don't do that unless provoked. the backfiring when turning off can be reduced if I rev the engine to about 1500 and slowly drop the rpms while turning the engine off. I have a leak in my exhaust manifold too.

A word of caution...I've lost two 12A's to backfire....sure they were long in the tooth to begin with, but they would've each gone at least another 6,000 miles without the death backfires...:cool:

well i have a backfire too on my se gone carby, when it was cold last night leaving work it start backfiring like crazy, then after awhile it just went away and cant figure out y