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Wrangler starts, runs for 3 seconds?

I've got a 2000 4-cylinder manual Wrangler. The other day, after stopping for a bit in the back-country of Big Bend National Park, we started experiencing a problem. The Jeep would start and run normally for roughly 3 seconds, then quit as if the ignition were turned off. I checked everything I could at the time, including fuses, relays, fuel delivery, and airflow. Fuel was near full and oil pressure read normal before the engine cut off. Problem is reliably repeatable (meaning I still can't get the blasted thing to run for more than 3 seconds). Couldn't find anything obviously wrong, which makes me suspect it's an "electronic" problem. Does anybody have any ideas what to look for?

After waiting for about 8 hours, the Border Patrol finally found us and dispatched a *very* expensive tow truck to haul us back to our RV. With the Jeep malfunctioning, we cut our little vacation short, hooked it up to the RV and drove home. I'm reluctant to take the Jeep off-road again until (1) I know what caused the problem and (2) have a way to fix it (at least temporarily) in the field should it happen again.

Thanks for your help, Bill

snipped-for-privacy@yahoo.com

Reply to
ElAlumbrado
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Reply to
Jerry Bransford

Were you using an after-market key, just recut from the original?

I had a key made at Home Depot, not realizing that it needed to the the electronic (encoded) key. It would crank, run 3 seconds, and shut off.

As Jerry noted, it may be security related.

--james--

Reply to
James

It shouldn't start at all if you have the wrong key. At work we have a cherokee and it's key fits in my ignition...and will turn it, but the KEY-shaped light comes on, on my console....no start though1

Reply to
SteveBrady

Nope, it will start even with the wrong key and then after the code is checked, the engine will be killed if the code doesn't match. I discovered this when I had an extra key made for my wife's JGC that did not have any kind of security chip.

Jerry

SteveBrady wrote:

Reply to
Jerry Bransford

Key is the same key I've been using for 5 years. Perhaps a sensor failure of some kind?

Bill

Reply to
ElAlumbrado

try the crank position sensor

Reply to
ISellJeeps

A friend of mine had a cougar that did the exact same thing. It was actually the ignition switch itself. The tumbler that the key inserts into. As it sprung back from "start" to "run" it would cut off. After starting it, I'd let go just enough to disengage the starter. It would run forever, until you let the key go.

Eric

Reply to
Eric

Reply to
Will Honea

Reply to
L.W.( ßill ) Hughes III

Reply to
L.W.( ßill ) Hughes III

Reply to
Jerry Bransford

Jerry, the link Bill gives says if the PCM does not receive a signal from the CPS within 3 seconds of cranking it will shut down the injectors.

That does imply the engine will start fine and then up and quit.

It sure wouldn't hurt to give the CPS plug and socket a quick clean with a contact cleaner spray.

Mike

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

Jerry Bransford wrote:

Reply to
Mike Romain

Reply to
Jerry Bransford

I just read it again carefully and it says it only 'looks' for the CPS signal on starter turning. If it doesn't get it after 3 seconds it shuts off the fuel.

I would think the same as you do, but that document seems to imply otherwise.

Mike

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

Jerry Bransford wrote:

Reply to
Mike Romain

I see where you're coming from Mike but without that timing signal, the engine cannot start since no spark can/will be generated.

Jerry

Mike Roma> I just read it again carefully and it says it only 'looks' for the CPS

Reply to
Jerry Bransford

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L.W.( ßill ) Hughes III

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mic canic

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