Author Topic: Motor Cuts Out  (Read 1126 times)

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JohnnyO

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Motor Cuts Out
« on: July 04, 2011, 06:55:49 PM »
I'm going to drop it off at the shop tomorrow anyway but I thought I'd get y'alls input.  This just started on Friday.  About two minutes after you start the Jeep the motor falls flat and you can barely keep it running.  It will sort of idle roughly but giving it any gas almost kills the motor.  Then after about 30 seconds it clears up.  Happens with the engine both warm and cold.  It sounds and feels like the timing is fragged except for the fact that the problem clears up.  Maybe fuel filter except that it is not replaceable unless you drop the tank and replace the pump.  I asked at the NAPA store once, they looked it up and said it's supposed to be good for the life of the vehicle...except that "life" is a relative term because it's 14 years old with 155,000 miles on it.
I did put new plugs, cap, and rotor in last year and there is only about 5000 miles on them.
I'm guessing fuel pump.  Anybody else have any thoughts?
Thanks.
« Last Edit: July 04, 2011, 06:58:12 PM by JohnnyO »

Offline grumpygy

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Re: Motor Cuts Out
« Reply #1 on: July 04, 2011, 09:06:26 PM »
May be something called a "Anti Drain Back Valve"  Also found where the intank filter is supposed to be changed every 60,000 miles.
94 YJ, Cool Air intake, 19lb Inj, 4.0 Throttlebody with spacer,  31/10.50/15's

JohnnyO

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Re: Motor Cuts Out
« Reply #2 on: July 06, 2011, 08:53:11 AM »
They started working on it late yesterday.  The suspicion is, and this is strange, that the inside of the muffler has rusted out.  The pieces floating around are blocking the exhaust, thus giving the O2 sensors a false reading and causing the computer to puke all over itself.

Offline sharpxmen

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Re: Motor Cuts Out
« Reply #3 on: July 06, 2011, 09:09:16 AM »
They started working on it late yesterday.  The suspicion is, and this is strange, that the inside of the muffler has rusted out.  The pieces floating around are blocking the exhaust, thus giving the O2 sensors a false reading and causing the computer to puke all over itself.

that's the catalytic converter, the honeycomb inside it breaks down and blocks the exhaust, the motor gets choked and loses power once you get more exhaust flow. It's not the O2 sensor giving false reading, the second one is not used for mixture but just to measure the cat efficiency.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
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JohnnyO

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Re: Motor Cuts Out
« Reply #4 on: July 06, 2011, 01:47:52 PM »
Well, we're back.  New muffler and it's fine.  Sharp, I just had a new cat put on last year.  One of the weirdest things I've ever had happen on a vehicle though.

Offline sharpxmen

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Re: Motor Cuts Out
« Reply #5 on: July 06, 2011, 05:02:42 PM »
Well, we're back.  New muffler and it's fine.  Sharp, I just had a new cat put on last year.  One of the weirdest things I've ever had happen on a vehicle though.

nevermind, i somehow thought you're talking about the cat (don't ask how i made the connection, it's weird and re-reading your post does not leave room for interpretation so it's all me).

I think was the same behaviour though and not O2 reading, exhaust choked and motor drowning in it's own fumes.
'95 YJ, NSG370 6spd / Hurst shifter, Dana 300 + 4:1 Doubler / tri-stick, Custom skid, Super D35 / Auburn LSD / 4.88, 35x12.5x15 BFG KM2, 64mm t/b, 1.7 RollerRockers, MkVIII e-fan, Dual Diaph Booster
Latest: Corbeau BajaRS heated seats :dance: keeping warm the rear end