PEAK PUTTERS

So wheeling last weekend.. and no issues on the trail..at all.. the jeep ran awesome then. Once off the trail on the road.. i start having studdering and then it lets out a big back fire. Then shuts off..u let it set for a few and it starts again. No issues then u get on it and it does it again.. no ideas right now?

Jeep 4.0 fuel injection. E2000 fuel pump. Ran fine untill yesterday. Now i checked the fuel psi at idle and it said 31. U hit the gas it falls to 28. U pull the vac it jumps to 40. Thats sounds good to me. But i cant check it while driving.. any other ideas. Now when u shut it off the thing drops to zero in like 5min..

I also have the dui livewires. And screaming demon coil. And there cap and rotor. Any one have any issues with these?..

Ok. So i got to start it today.. and fired once and then nothing.. i check to see if there is spark... And none.. i unplug the battery for a few seconds... Then it fires right up.. i pulled the thottle body and clean it all up. I pulled the o2 it looked fine. Pulled the crank sensor. And just wiped the dirt and oil off.. Checked for vac leaks. Dont seem to be any. Tomorrow i am going to swap the fuel pump to see if thats it..

I dont have a cel due to not having one wired up.. so its about that time to just throw parts at it and see what helps lol..

Question, you said that you have no spark so why are you thinking vacuum or fuel pump? Could you check the spark out of the distributer to verify it's operation while cold and then hot?

Not a jeep guy but don't those things have crank sensor problems? Sounds spark related not fuel. If you lost fuel pressure while driving it would lose power and die like its running out of gas. Not backfire. Most likely an ignition problem.

Lurch wrote:Not a jeep guy but don't those things have crank sensor problems? Sounds spark related not fuel. If you lost fuel pressure while driving it would lose power and die like its running out of gas. Not backfire. Most likely an ignition problem.

Yep, many a Jeep has been bought for cheap by a dude with a new CPS in his pocket.

Yea i am just going to try it. Becasue it drops below 30psi at idle. And does not hold psi.
It only did not have spark once. All the other times it died it had spark. I was thinkin more of the pick up in the distributer. But some other guys said they had the same problem and it was the o2 or a bad coil.. i hope the coil is good since its only 3 months old.

And when i was driving home from the trail it was acting like it was running out of gas..

So i swapped the pump. And added another ground. And the pump works and sounds better. And holds psi. Now it did not fix the problem. So i am going to go though the list. Cps. Distributer. Coil..

ok changed the pugs cap and rotor, o2, cps cleaned the thottle body and fuel pump. i am still setting at 30ish psi at idle but it will go to 40 with the vac unplugged.

the jeep runs better but hesitates at lower rpm, whats next on the list? i think there is a vac leak at the brake booster, you can hear it from inside the cab, and once you hit the brakes it stops, could that be making it run lean?

so i unplugged the brake booster and pluged it off, drove it down the road and no problems. so i am going to change that and hope fully its done.

nope drove it again and it did it again.. not as bad but still sucks

so funny thing today.. i figured i would try the old carb trick and rev it up and stick my hand over the intake.. thinking it would die and do it again. well it did not die i have the thottle body covered and it was still running.. so i search around to see if there is any more leaks, its the brake booster.. lol so its for sure toast now. it was sucking enought vac to keep the thing running lol..