Hi all. Posting for 7.3 friend. He's got a 99 7.3. When the truck is running. It runs great. But, he can be driving along and all of the sudden. The truck shuts off. Sit for less than a minute and she'll fire right back up like nothing happened. This can occur once a week or a month or two and happen again.

He's replaced the PCM and I've mentioned that he needs to check all ground sources, battery cables and charging system.

Just seeking some more additional feedback on possible causes

Thx in advance.

 

A ground high on the firewall about 10 inches from the DS fender, and another on the DS fender adjacent to the airbox are common corrosion points. The one on the fender is right up under the lip where the hood rests, can be hard to see.

The relays in the fuse box under the hood can be swapped around. A weak one there powering the PCM could do that.

A similar condition on mine was the ignition switch that mounts under the steering column. The symptom was very brief tho, just a blip and keep running unless I was at a full stop.

Couldn't hurt to check that the tin nut on the back of the IPR is tight.

Any codes?

 

Does it have an aftermarket ICP sensor on it?

The aftermarket units have proven to be poorly shielded and allow for EMI to casue the engine to shut down. One boardemner could kill his truck by keying a little hand held walkie talkie, another had his shutdown every time he drove past a large power relay station. Both were running aftermarket ICP sensors and the cure was a OEM Ford replacement.

 

Thank you for the replies. I will pass the information on to him and direct him to this site.

Don't know about the ICP. I'll ask.

No codes that i know of.

Thx again.

 

Cam position sensor (my first thought).

 

What he said, was my first thought also.

 

Yup.............

 

I have the truck and same problem.


I caused the issue. I put a chip in and when I replaced the PCM I didn't tighten the 10mm bolt thru the firewall enough (was scared).


Have your buddy (since he recently replaced the PCM) start the truck and reach over while it's idling and try and wiggle the PCM and see if it dies.


I lucked out after having mine towed to the dealer and they couldn't get to it for a few days so I dinked around and did the wiggle test on everything while it was idling to see if I could find the fault.


While up under the dash I hit my pcm with my elbow and the truck died. Started it up and tapped on the PCM and she died again. Tightened up the 10mm bolt on the firewall and she's been rock solid ever since.


Good luck. (If it starts and idles, just start there and start wiggling wires).


Denny

 

Thanks for that info. Certainly we'll check thst one.

Also, CPS. I forgot there was a recall on those. Mine was replace on my 2k dually when it went in for the water pump.

 

yep my first thought also.