Greetings,
I have a '96 F350 7.3L 4X4 Crew Cab that cranks but won't start. I've done all the work on it since new except when I paid a dealer $400 to replace a crank sensor (!@#$$%!!!... never again!) The odometer now shows 350,000 and my pride just won't let me turn it over to a dealer and I can't find anyone else to work on it (and don't want to either.)
It was running fine then one day wouldn't start. Here's what I've done so far:

Checked the fuel system. It gets pressure to the fuel rails.
I planned to check the oil in the high pressure pump... but read on.
All the fuses and the diode are ok. All the relays around the engine compartment fuse box are ok. I plugged in my OBD II which powers up but won't communicate with the computer. I'm assuming I need a new PCM.

At other sites, e.g., Dieselman, I read that there is a PCM and an Injector Control Module. The electrical schematic in my Haynes manual shows the PCM but no injector module. I removed what I think is the PCM, an aluminum box measuring 6x8.5x2 inches that was attached to the inner fender panel adjacent to the engine compartment fuse box. Written on it is "IDM-100 SAEO
F6TF-12B599-AA PWB 4130
6E10-2
6FAA0"

Is this the PCM or the ICM? Is there even an ICM at all? I noticed there's another module behind the glove box very close to the OBD connector and wonder what it might be. I wonder if there's anything else that might be wrong besides a PCM failure. Any help would be appreciated.

 

The first thing I did was replace the crank sensor

 

First of all, Welcome to FTE.
You came to the right place to avoid the high costs of a dealer.

The part you removed from the fender is the IDM. The PCM is bolted through the fire wall. Behind the parking brake. You will need to remove the driverside inner fender liner.

Does you cigar lighter work? PCM and lighter share the same power supply.
Do you get smoke out of the tail pipe when cranking?
Does the tach move while cranking?

 

Like Jim said welcome to FTE! Also he is spot on.
here is a picture that will help with PCM location


Double check fuse 22 in the engine compartment. It powers the PCM, fuel heater and glow plug relay. The Fuel heater is a very common failure to blow that fuse and get a no start.

 

Is the wait to start light functioning normally ?..

Is the check engine light on all the time ?...

 

Thanks for all the help.
I see the PCM now.
Fuse 22 is OK as is the PCM relay.
The glow plugs power up.
The lighter works.
The tach moves when cranking.
No smoke.
The wait to start light goes on but there is no check engine light.

I'm going to pull the PCM now and make sure it's getting power.

 

PCM is getting power. You would not have a WTS, GP's or tach signal is it wasn't getting power. There is still an issue with the OBDII connector but I don't believe you will find an issue with the PCM itself.

 

What OBDII scanner are you using? have you used it successfully on this truck before? There are many scanners that won't work on the PSD even though they are OBDII

 

It's an Actron CP9180.
No, I've never used it before.

 

Its probably the scanner then. I think we have run into this many times with the Actron scanners.

 

I would go ahead and check your HPOP level as well as your oil level itself. Oh and to answer your Question no there is no ICM They probaly ment the IDM (Injector Drive Module) any how check that and get back to us and someone should be able to get you goin soon.

 

I talked with a diesel tech across town and he told me that if I'm getting power to the PCM and the Check Engine light doesn't come on then either the PCM is bad or there's a problem with the ground. The trouble is that there are about 96 pins on the plug and my Haynes diagram shows only 60 so I have no idea which one is the ground. There are several pins showing about 2 ohms though.
I talked with a guy at Actron and he said that their scanners might not work on this vehicle and of course he blames Ford. The packaging said it would work though so I'll try to take it back.
I found a PCM nearby for $220 so I'm gonna bet my money on it.

 

The CEL should come on for a split second with the key on ,,are you sure the bulb is not burned out ?...


Pinout here ...

 

PCM seldom fails. When you had the IDM out did it have any water in it (shake test)? Water tends to drip off the fender and finds its way into the IDM.

 

Thanks for the diagram Rick. Do you have something that explains what each pin is for? My diagram from the Haynes book gives little usable info. Where did you get the diagram anyway? Is there one for the IDM? By the way, which pins are for the grounds?

I checked the HPOP and there was no oil in it. So I filled it but still no start. How can I test to see if it is working?

When I turn the key on I get the "Wait to Start" light. When I crank it I get "Water in Fuel" "Engine Temp" and "Fuel Filter" lights but no "Check Engine". The diagram for "Diesel Warning Lamps Display" doesn't show a CEL but I do see one on the Instrument Cluster diagram but it's for gas. I could sure use a better diagram.

No evidence of water in the IDM.
I guess I could replace the IDM too. It would still be cheaper than having it towed to a shop, assuming that I don't eventually have to do that anyway.