Recently developed a problem....

'97 F350 PSD, 4x4, std, 6637 mod otherwise stock, over 600,000km on the truck, about 130,000km on the motor.

It just cuts out, at any engine speed, idle to wot. More frequently when cold. I have noticed a roughly 50rpm drop, and instant recovery, at idle every 15 - 25 sec for a while. But since the temperature dropped below feezing it will cut out all together, droping several hundred rpm and "catch" itself just before stalling. It doesn't run rough, just cuts out as if turned off and back on with the key, injectors just not firing. This seems to be less frequent at higher ambient temperatures (-10C +) and as the engine warms up, but even though I have my winter front completely closed, the coolant temp rarely rises above "C" on the gauge. Most days temperatures are between -35C and -20C, without windchill. I run Shell Rotella T5 0w30 and the truck starts fine, without being plugged in even at -30C, I have not noticed longer cranking to start, the problem only manifests itself once it running.

First thought was CPS, installed a new one I cary in the glovebox, but there was no change. I suspect the IDM, but do not have a spare one to swap in to test. Am I on the right track? Any suggestion?

 

That's what I'd try if I could find a spare. Do you know of anybody with a truck like yours or even a super duty with a 7.3 to borrow and try? I'm not an expert by any means so more will chime in too I'm sure.

 

sounds like a loose connection somewhere from the cold. That circuit board in teh IDM sure could be it. Can you open it up and look for bad solder joints? I noticed on GM trucks back in these years they had bad solder joints like crazy and they usually popped right out at you when you look at the board. And were usually easy fixes.

 

Thanks guys. I'll try to get another IDM to swap.
Which brings me to another questions. Are all 94.5-97 IDMs the same? How about interchangeability with 99-03?

 

99-03 Super duty ones are an upgrade to ours. Get one of them if you end up needing one and can. They send 120V to the injectors where ours send 100. You can try any from 94.5 to 03.

 

Thanks for the quick reply.

 

Some advice, if it is the IDM, do not do any business with any company listed in Jacksonville FL as they are a ghost and will take your IDM and your $$$. Happened to me but my cousin works for the FBI there and he went and got it back for me. Co was in an empty wharehouse, picking up mail on Fri nights.

 

Forgot, Ford is famous for getting water into them. Happened to mine.

 

i have run both idms in my truck the 100 and the 120 for a test to just c either would be fine. i had one truck 97 psd did same thing u can try grabin the harness goin to the computer it self and just move the harness around to c if engine dies may just have a bad wire.Also there is a ground wire i belive attaches to the bolt that holds in trans dipstick make sure it has good connection i would wiggel the harness for cps too to c if bad wire.mine took 2 or 3 months to find,intermittent electrical probs are the worse

 

did you ever fix this issue?
What was the final fix?



.