1990 7.3 PS, 193,000 mi, I was driving down the road when the engine starting running rough. Check Engine light flashing, overdrive light on shifter started flashing, water in fuel light flashing, then the engine stalled. The lights kept flickering and it sounded like relays under the dash were chattering. I turned off the ignition, and tried to restart. The lights stopped flickering but the "wait to start" light didn't come on, so I tried cranking the engine. She had more than enough power and was cranking fine, but No luck starting! After 4 or 5 times of turning off and on the ignition, the "wait to start" light finally came on, and the engine started. I put it in gear and drove about 2 miles and again, the same thing. This happened 5 times before I got home. Any ideas? The batteries are fine, and the alt is cranking over 14 volts. Batteries, Cam Position Sensor, and fuel filter are new.

 

A 1990 model?

No WTS light is often times a shorted fuel bowl heater in the 99 - 03 trucks. Most other issues cause the WTS light to stay on and not shut off.

Let's clarify what year truck you have and move on from there.

 

My bad, It is a 1999, F350 SuperDuty Crew Cab, 4 x 4, 7.3 automatic trans.

 

On the Powerstroke forum, I was told that there could be a ground issue with the PCM! Sound plausible?

 

The 99 makes more sense. I just wish your issue was as easy. We do have a 99 - 03 7.3 diesel section you may want to check into.

Running rough with CEL & WIF light would make me first inspect the main engine wiring harness. It's a thick wiring harness with red stripe tape around it. It comes up and over the driver side valve cover under the air intake tube.

Check to see if that wiring harness has shorted against the valve cover below that square box with a bolt in the middle of it, or if the wires behind the box have shorted against the bracket.

Starting the truck up and performing the wiggle test should also give you an idea of where the issues are at.

 

Ok, will do! I live in the midwest, and we have a lot of salt on the roads, I was also wondering if there could be some corrosion on the grounds? But I will perform the wiggle test. Do you have an idea how much the harness costs and how hard it is to install?

 

Also, I noticed there were 2 relays on top of the engine, 1 is for the glow plugs, what is the second for?

 

Loose or corroded grounds could do it too. It would be a good idea to check those too. If you find a short in the harness, just tape up the wire. No need to replace the harness.

The 2nd relay is your air intake heater. It doesn't really do much and is not needed, but comes in handy as a spare for your glow plug relay if your GPR goes out.

 

OK, checked grounds, found nothing, did the wire wiggle, nothing. However, I do have a DEI Clifford Romote Starter/Security system. Read a couple of posts for other problems that tell folks don't ever put one in your truck. Well, I took a look under the dash and there is nothing but a cluster of wires, a relay block of 4 relays and a couple of control (Black) boxes under there. I am beginning to sense this is my problem? Anyone ever have a problem with these?

 

Ok, after 6 days in the shop, and a grand later, they replaced the PCM. Been driving it a couple of days now and she runs like a dream.

 

glad it's up and running for ya!!

did they figure anything else out? like maybe why the PCM died?

 

Too bad it took the shop to figure out it was the PCM. You could of gotten a new one set for OEM from DP-Tuner for about $400.

 

I had 2 fuses blown. One for the fuel heater and another the horn. I had checked the wiring harness and couldn't find anything wrong. Replaced the fuses did the wiggle test, nothing blew, but the motor stalled again. At that point, I took it in. My mechanic is an old timer, who doesn't rip people off (very rare these days). Most of the time was labor to diagnose. He only charged $450 for the PCM and $85.00 for and oil change (which he has to do per my extended warrentee). But he will not give it back until he is satisfied he found the problem. He also told me what I already knew, the the harness looked like the day it came off the assembly line (didn't try to B*LLS*#t me). It's hard to find guys like him. I love my truck and have taken it places no one else would think of going, never failed on me. I consider this lucky. My friend took his 2002 F350 into Ford because it wouldn't run right (idle) and the dealer changed a half dozen sensors, a wiring harness, and the PCM, and it cost him $2800. Never really knew what part failed. So considering he only changed 1 part, and the truck has been running great, I'm happy! :-) Thanks to everyone who tried to help, that is what makes this forum a great source of information.

 

I dont know if I missed it but did you unplug the bowl heater?