89 YJ Started back firing

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89 YJ Started back firing #810788 05/09/07 06:15 PM

Joined: Apr 2006

Posts: 46

Bayville, NJ

RLBomber

Getting the Wheeling Fever

I haven't had a problem in almost a year (knock on wood), but now the jeep is back firing when slowing down. I let off the gas and use the engine to slow and it will back fire a few times and it never did this before.

4.2 / manual has new plugs and wires, cap and rotor. It does have an after market Howell TBI as well.

My first thoughts is that I have a leaky exhaust and will be checking that out. But wouldn't the timing if off cause this as well?

Re: 89 YJ Started back firing [Re: RLBomber] #810789 05/09/07 06:21 PM

Joined: Oct 2006

Posts: 2,079

Arlington, Texas

Brown81CJ5 Offline

Body Damage is Cool

You can start by checking the timing. If that does not solve the problem then check cylinder compression.

Gun it and run it!
1981 CJ5,258,T-176,D300,AMC 20,Dana 30,Trxus M/T 31x10.50, Rancho 5000's, GroundPounderFab front bumper, polyethylene gas tank, aluminum dash, AutoMeter gauges

What this country needs is unemployed politicians.

Re: 89 YJ Started back firing [Re: Brown81CJ5] #810790 05/09/07 08:56 PM

Joined: Oct 2003

Posts: 7,768

Central Texas

BigJim

Web Wheeler

Backfiring in the muffler/tail pipe is sometimes a result of unburnt gas making it's way to a hot spot in the pipes and igniting there. (sometimes)
If you are changing gears to slow the vehicle...1/4 ton vehicles have enough brakes to do the job...braking with the gears is not required.
But you could have a leak in the manifold or pipe that is sucking air in there too.
Big JIm <img src="/forums/images/graemlins/pfft.gif" alt="" />

professional bovine relocation specialist

Re: 89 YJ Started back firing [Re: BigJim] #810791 05/10/07 03:53 PM

Joined: Apr 2006

Posts: 46

Bayville, NJ

RLBomber

Getting the Wheeling Fever

Well, it turns out to be the exhaust pipe, found the hole.

Anyway, thank you for your input.

rlbomber

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