Intermittent shut off problem

[wagonguy]

Hi guys. Noob here. I searched and have been trying to find some ideas, but I haven't found anything concrete.

My 03 has been randomly shutting off. Sometimes under acceleration, sometimes cruising through a parking lot, warm, cold, lights on, lights off. Can't find a pattern. I tried switching keys thinking PATS, but if anything, it was worse. Sometimes it just "blips" enough to kick off my cruise, but doesn't completely stall. Sometimes dies completely. Red light on dash comes on solid when it does it. Speedo goes to zero, everything electric (lights, stereo, etc) still works. Always starts right back up.

Would it be unusual to have 2 bad chip keys? Has anyone had a PATS failure that wasn't the keys, but whatever is reading the keys? I love this car, but I fear I bought someone else's headache. :depress:

Doug

[Pat]

1st thought - fuel pump. But changing that can be expensive if you can't do it yourself and without supporting data. But we have seen similar reports.

[RubberCtyRauder]

make sure your battery is charging by using a volt meter. should be 14+ when idling. check battery volts when off. electrical gremlins can be tough to find, all grounds need checked, the wire harness behind driver cam cover can get rubbed thru a screw /stud that is there

[wagonguy]

Thanks guys. I read some threads that suggested fuel pump, but symptoms didn't seem the same. Mine doesn't run rough or stumble, just off. Then always restarts. Seems very electrical. I'll check behind the cam cover.

Doug

[wagonguy]

12.2 volts while off, 13.6 at idle. Little low. Might be time for a battery.

[RubberCtyRauder]

what is your rpm at idle? maybe the previous owner put underdrive pulleys on? if so tge idle needs to be bumped up. alternator would mean battery volts reads low at idle. these alternators are kinda specific. needs a 4g

[justbob]

Any chance you have a tune on a chip?

Mine was randomly shutting down years ago and the copper contacts on that old chip were just starting to oxidize. Pulled it out, cleaned it up and duct taped it firmly back in and problem solved.


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[johnjamis]

Any chance you have a tune on a chip?

Mine was randomly shutting down years ago and the copper contacts on that old chip were just starting to oxidize. Pulled it out, cleaned it up and duct taped it firmly back in and problem solved.


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I had an MSD ignition on my corvette that caused the car to shut down randomly as if the key was shut off. Then, it would restart fine after a minute or two. Replaced MSD; never did it again.

[JimP]

I've repaired three Marauders, a grand am, two Nissan xtrails and an Impala none of which threw codes. They were all doing what your car is doing.

In addition to the suggestions above, I would strongly suspect the crankshaft position sensor, when the sensor fails it kills ignition and the car just stalls no stumble no warning.

It usually fires right back up afterwards. On the MM the sensor is hidden behind the ac compressor but it's doable. Let us know how you make out with this.

[wagonguy]

Any chance you have a tune on a chip?

Mine was randomly shutting down years ago and the copper contacts on that old chip were just starting to oxidize. Pulled it out, cleaned it up and duct taped it firmly back in and problem solved.


Sent from my iThrone using Tapatalk

The car came with an SCT tuner with Lidio tune. Not sure about a chip. I'm new at this lol

[RF Overlord]

If you have a tuner, you don't have a chip.

[wagonguy]

Getting some strange readings on my volt gauge, I'm thinking alternator. Just bought one and I'm picking it up today. I'll post the results.

[BLACKMARAUDER04]

I have had 2Motorcraft rebuilt Alternators fail since August.
These remanufactured units do not put out constant voltage.
Mine will jump from 13.8 down to 11.2.
Luckily, The dealer has warrantied both repairs.

[wagonguy]

I have had 2Motorcraft rebuilt Alternators fail since August.
These remanufactured units do not put out constant voltage.
Mine will jump from 13.8 down to 11.2.
Luckily, The dealer has warrantied both repairs.

I too have had terrible luck in the past with remans. I went the new route. I bought a new Duralast from Autozone. The one I took out looks to be original (dated 2002). Think I'll keep it, because I'm a geek like that. So far so good, volt gauge reads better at idle.

[RubberCtyRauder]

find a alternator / starter repair shop and have it rebuilt and have ready

[wagonguy]

Same symptoms, including voltage dropping. Next is Crank Sensor.

[wagonguy]

Crank Sensor didn't fix it. Back to the drawing board.

[GetMeMyStogie]

There's also a camshaft position sensor, works the same as the crank sensor. Before throwing in a new one though, have a close look at the wiring harnesses around the engine. Follow every inch, especially in the tight spots. Look for anywhere a harness rests on some other part (where not attached or held in place on purpose), get in there and pull them apart - look for chafing that has worn through the insulating layers to the copper wire within.

While changing out my BCM yesterday, I noticed a part of a harness sitting tight against what I think are the fuel lines, at the back of the pass. side head. No clip or hold down on the wires, so I got in there, separated them (nevermind the crunchy sounds) and saw that the corrugated sheathing had completely worn through. Luckily, the insulation on the wires was intact, though nice and clean from the constant chafing. The outer cover of the fuel line is also worn through at that spot. (fwiw, I twisted and shoved the wiring harness into a different position, so it's not chafing any more)


Did you check for stored OBD codes?

[wagonguy]

Yeah, no codes. I think I got it, should have went with my first instinct. Put in a new battery and have gone 2 days without a shut down (knock on wood). Battery I pulled out was slightly bulged on one end, even though it was only 2 years old. Sarted the car fine, but must have been intermittently shorting internally.