My 97 Ford F250 7.3 w/ 191,000 mi. quit running while I was on a city street waiting for a green light. It just quit like it had been shut off with the key. Emmediately I noticed I had no "Wait to start" light. I had it towed home and started investigating. I checked all the fuses and 9 & 22 with my volt/ohm meter. I hooked up my OBD ll scan tool and haven't been able to get it to connect. It reads "failed to connect". I checked the scan operation and tryied again, NO LUCK. Now I'm wondering if I should pull the PCM, which requires removing parts of the fender. Has anyone had this happen to them? Two years ago I had to replace the glow plug relay ( I bought it at Auto Zone). One year ago I replaced the throttle postion sensor.

 

More than like likely your PCM 30A maxifuse has blown. In the main fuse box under hood, it will be in the middle row of maxi's closest to engine. Probably due to fuel heater plate in fuel filter housing that sits under fuel filter itself. Remove FF from housing & drain fuel out, you will see a metal plate with a circular metal wire soldered to plate. If metal ring is no longer soldered to plate, it shorted and blew PCM fuse as it shares same. You can remove the wire from driver's side of filter housing that has a large rectangular insulator on housing or remove plate under plastic stem that filter slides over and remove wire connection inside. If you live in cold climate and want to keep fuel heater intact, it costs around 100$ at Ford dealer. Otherwise w/ low sulfur fuel, you pretty much don't need it. Oh yeah, plastic stem in FF hsg is LH thread and should be able to get out with long handled angle pliers or crows foot wrench. Check it out, common failure.

 

I need help, I have a 96 f350 7.3 and the #22 fuse had blown and now I only have power to on side. The fuse is good

 

Thx, dieselrick. The fuse #22, closest to the engine checks out good. I checked the heater's trio of soldered connections under the FF and nothing looks wrong. In the past with my OBD2 scanner giving codes I was able to fix the P0221 Failed pedal assembly, and P1391,P1393 Faulty relay (My 97 only has one). At that last repair the scanner read P1395 Glow plug monitor fault, after replacing the Glow plug relay the scanner showed no codes. and it ran great since 9/11/2014. Now I wonder if I should have spent the $189.00 for a GPCM and ordered one from Auto zone. What do you think?

 

Is this a CA CARB truck? I have never seen a 94-97 with a GPCM. The vehicle PCM controls relay operations in non CA trucks. Your scanner does power up ok when you plug it in? Does your WIF & FF lights come when you cycle key on?

 

Yes, on the hood it's got tags, this is a California labelled truck, OBD2 certified. No, my scanner doesn't power up. And yes, My "water in fuel" and "fuel filter" lights light up when i turn the key to start.

 

Here's photos. My diagrams show more parts than my engine has, like there's a two box GPCM shown but my engine doesnt have it there . I think it's attached to my Fuse box ??

 

Power for the scanner is supplied by the cig lighter fuse under dash but not the Gpcm. You are probably on right track with it, but check cig fuse and scan before replacement. You'd think regular PCM relay management could be programmed in for CA trucks, but a separate module for glow plugs is just more parts to sell. Hint to keep glow plug system healthy, replace relay yearly cuz the current draw creates carbon buildup on contacts of relay & they sometimes will weld together & kill batteris while driving leaving you stranded. Have seen a dozen or so of that. Also, when at home, use your block htr when ambient is less than 45 degrees to save GP system, batteries, starter, etc for when you really need them. Good luck.

 

Those relays are normal on all strokes. 1 is for PCM power don't remember the other. The only GPCM I know of goes on IDI engines

 

The 2 box module I think you're talking about I've seen on Ca 99-03 Super Dutys & all Excursions, all 6.0 and it is a solid state relay and it mounts where your relay does. They rarely fail. If you plug in the block heater for a couple hours, will it start?