Pulled the fender liner out to get better access to the PCM wiring. I looked all the wiring over one by one and found no flaws. Cleaned it all out with contact cleaner, then hooked the PCM up right there at the front tire. My plan was to wiggle each individual wire until the truck died, only problem, I could not touch the PCM without it stalling. I reinstalled the PCM back in its usual spot. My new plan was to wiggle wires while it was mounted up. I started the truck back up, and before I got out to go to the front fender, decided to give my PCM some soft taps with the handle of my ratchet. When I tapped the lower corner closest to me, it died. So now im right back to PCM. Called http://dieselecmexchange.com/ and left a message. Waiting for them to call back so that I can get some return postage and send it back to them. I cant imagine that this is normal for a PCM. I did not take a big swing at it, I VERY lightly tapped it.

 

I wonder if it's grounded properly. There is some sort of grounding clip on it inside the cab but I don't know the specifics on it.

 

It also grounds through pins 25, 51, 71, and 103. Check those for continuity. Also consider checking continuity between the 42 pin connector and the PCM connector and other places the PCM harness leads.

 

Been doing some reading this morning about the PCM ground strap. I do not believe that metal tab is on the case. Could the sensitive PCM really just be a housing ground? If so, I can make a way better one then that tab.

 

I have no idea on that, let us what you end up doing.

 

I installed a Hydra chip on my truck and their instructions have you leave that ground tab off, which tells me the grounding through pins 25, 51, 77, and 103 are sufficient.

 

Just finished with some more troubleshooting. Checked the ground pins 25,51,77, and 103 (How convenient that the ground wires were all right there on the edge of the connector). All of them were good. Wiggled and pulled while it was hooked up to the meter, all good. Found my ground strap tab in my door cargo area, installed and it did not improve anything. I even ran another housing ground wire off of the PCM and still wants to die. One time it was not idling right, so I stepped on the gas, it reved up and then died. Did not want to start back up. I wiggled wires around, didnt help. Then, while cranking the engine, I took my wire strippers, and used the rubber coated handle to gently tap the PCM...fired right up. I think I am going to have to send my PCM back. It has a warranty so I wont be out any more money for it, just have to wait another week!

Anymore ideas guys? Its hot outside and i worked 12 hours, so I am calling it a day on the truck. Will take ideas and opinions and try them out tomorrow. Probably not going to ship the PCM out until Monday.

Also let me add, thank you all very much! I really appreciate all the help and ideas. If the PCM is not at fault, I am going to have to take the truck to Ford. It is admitting defeat for me, but I have got to get this figured out, it will be one year in October!

 

I suppose that there is a warranty condition that the case cannot be opened?

I almost suspect a loose component or a circuit trace is making intermittent contact with the case.

It is too late now, but a trusted PCM tech is Jonathan at Diesel Tech Chattanooga.

 

It has 2 seal stickers on it. "Warranty void if removed". Super insulting but I will follow their petty rule, I only want to pay for that once.

 

⬆️⬆️⬆️ Yes, I remember that from PHP instructions all the way back to the 6 position chip days. They state the ground strap is not needed and to remove it during chip install.

I agree this totally sounds like it’s inside the PCM. Hopefully they are good to work with on the warranty aspect.

My Edge CTS asks for my vin every time it has been disconnected from the OBDII port. Usually it has remembered the numbers and I just have to click that they are correct.

 

ObiWan, hopefully the new PCM solves the problem. If not I think the next step would be to get a pin removal tool to take the pins out of the connector (only one at a time) and check the connections.

 

It used to just ask what the model was, (Ford). When I got the PCM back from repair it started verifying the vin number. I am ok with it, just wanted to take note of the occurrence.

 

PCM came back from repair but no difference. I still dont know if this rules out the PCM though. Please if anyone knows, tell me im wrong but I dont think it is a wiring issue if slightly tapping on the end of the PCM makes it idle different. Is this with all PCM's?

When I first installed the PCM it would not start. Used the old trick of giving the PCM a gentle tap while cranking and it fires right up. wiggling the wires close to the PCM makes the idle change, once while running I gave it a gentle tap, died, another time made the idle sound out of control, pushing the wire connector of the PCM made it smooth out.

The place I used in NC seemed like a good business, but maybe not. Should I send the PCM to the guy in Tennessee before I try anything else? Tomorrow I am going to start searching for the best 7.3 shop. If anyone in Kentucky has anyone that they go to, please let me know. Thank you.

 

If it was me I think the next step I would take would be to get a pin removal tool and remove and repair any damage to the wires/pins coming into the PCM connector.

I highly advise only doing one pin/wire at a time to avoid confusion or mixing up wires.

if wiggling the wires, or tapping the PCM creates/solves the issue I think it’s a loose wire making intermittent contact.

 

Gotta agree with Ztodd377. This really seems like wire issue at the PCM plug. Suspect wire broken or loose where it goes into a pin. Long tedious process to depin each wire but finding a wire harness would be the other solution