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Rough idle when hot

Hi all,

I've got an '82 Scrambler with the Mopar fuel injection kit (so anyone with a '94 Wrangler can help out too :). On my way back from a very long road trip, it started running rough every once in a while. This is while I was going about 70 MPH down I-20. I made it back without incident, but it's been getting progressively worse. Now, after running for about 5-10 minutes (cold or hot), it'll start to miss, then backfire, then finally the engine will die. I can re-start it in a few minutes and run for a while again, but will soon start to miss, backfire, then die.

The engine and fuel injection kit have been in for about two years now, and were running OK up to this point. I thought I might have picked up a bad batch of gas, so dumped in some "Sea Foam" to absorb any water, and replaced the fuel filter - neither had any effect, positive or negative. I also went back to slightly hotter spark plugs I used just before I left on the road trip, which also had no effect.

Any hints on how to solve this (or where to begin) would be greatly appreciated.

Thanks in advance.

Reply to
Michael White
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Reply to
L.W.(ßill) Hughes III

When was the last time you changed the air filter on the gas tank vent? A vacuum on the gas tank can sort of act like that.

Mike

86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00 88 Cherokee 235 BFG AT's

Michael White wrote:

Reply to
Mike Romain

Mike,

Are you referring to the one in the Charcoal cannister? If so, that whole setup when in about two years ago. The air filter (K&N from the Mopar kit) I cleaned a few weeks ago. Is there another filter I should check?

Thanks.

Reply to
Michael White

I used to plug up the filter on my canister almost every time I went to 'play' in the local mud pit. There were many trips home with the gas cap cracked open so it would run at speed.

I then moved the canister up under the brake booster so the tires couldn't fill it up with mud any more.

If you drive on muddy or even dusty roads, that filter will plug up.

Other than that, I don't know the system you have so can't help.

Mike

Michael White wrote:

Reply to
Mike Romain

Bill,

Thanks. Your suggestion set me on the right path. Turned out to be a bad fuel injector. After eliminating the ignition coil, then the other ignition components, I listened to each fuel injector with a 3/8" extension. Five of my injectors make a nice periodic tick (tick.....tick.....tick.....), while one sounded like it was about ready to have a heart attack (ticktickticktick..ticktitickticktick..tick...tick). Hopefully, that's it. That would explain the backfiring, as fuel is being continually dumped into the chamber, and the rough idle, as that injector was taking fuel from the fuel rail when it shouldn't, starving the other injectors.

I've had injectors fail on Nissans before, but never like that (always fail dead) and never that soon (the Jeep's are less than two years old). Chrysler quality?

Thanks again.

Reply to
Michael White

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