I have a 2000 F250 SD 7.3. It had a power chip plugged in to it when I bought it 10 years ago. Shortly after the extended warranty ran out it died. I saw that someone had stuck a matchbook along side the chip. I wiggled it and it started. This would happen only a couple times a year but the other day it happened and I wiggled it, drove for another 5 miles, died again. After 5 more times I had to get a tow, it got to where it would idle but not accelerate. It was full of oil. Half way through all this I pulled the chip but all I got was what sounded like spark knock while going down the road. After sitting in my yard it started and ran. I installed a used PCM and pulled the wire that grounded the MAP sensor for the power chip and drove it 15 miles without a problem but got back home and it died in front of my house . In the amount of tim it took to walk to my shop and get a tester, it started but would die on acceleration. After sitting a little longer testing the fuses, it drove up to my shop. I pulled codes and got a keep alive ( I don't remember the #) PCM code that is a power loss I guess. I have now replaced the PCM power relay and piggybacked a wire to the MAP to the inside of the cab so I can monitor the 5 volt PCM power if it dies again. I intend to wiggle all harnesses this afternoon and then take it for another ride. Anything I may be missing?

 

It sounds like you have a plan to start with. What scanner do you have? Can you monitor live data? If so, look at Injector Control Pressure (ICP), Fuel Injector Pulse Width (FIPW), Injector duty cycle, and engine voltage to start with, and we can go from there.

 

My scanner will only show the MAP sensor feed and RPM.

 

Oh boy, that is a little bit of a problem. Cheap fix for that (under $100) if you have an Android phone is to get a wifi or bluetooth OBDII adapter. You can download Torque Pro for around $6 from the app store and then get the information we are looking for. The other way to do it would be to get Auto Enginuity (AE) with the Ford enhanced bundle from someone like Clay at Riff Raff Diesel and a laptop or tablet and hook up and then we are really cooking. Not counting the laptop or tablet you are looking at $359.

 

Or we can just do some educated guessing. If I were doing that, I would start by checking the under valve cover harnesses making sure they are plugged in and making good contact, next I would pull the ICP connector, located on the front of the drivers side head. It is threaded into the oil rail on that side. It has a three wire connector and if there is oil in the connection, it means that the ICP sensor is going bad and can should be replaced. Not too bad. lay has them as well.

Injection Control Pressure ICP Sensor 97-03 - Riffraff Diesel Performance

Start there and see what you ind.

 

I will check that later. I have a ton of stuff to do today and maybe make some money to fix this. I went to the PCM first because that was the problem with that chip for so long and thought it finally took out the PCM. I will be back on here when I get back later.

 

No oil in the ICP plug or any other for that matter. I started it and idled for 5 minutes while I wiggled all the wiring harnesses I could get my hands on, and nothing. I had replaced the PCM relay and I notice the new one gets warm. I am wondering if the relay was getting hot and opening. I guess I will have to take it for another ride tomorrow.

 

A quick free thing to check is to see if your IPR nut is still on the IPR. Make sure it's tight (if you can move it with your fingers...that's bad).

Has this truck ever had the CPS replaced? It may be one of the old black ones, which happens to be under recall. A new Ford CPS is about $20 or so (don't get a generic). Takes 15 minutes to replace with a small 10mm socket and a flathead screw driver.

But I agree it could very well be a possible loose UVCH harness, it's just a lot of work to check those. Do the easy stuff first.

 

Can you make a video of it starting, running, and dying... then post it on YouTube or something, and link it?

"It starts, it dies, and it has a hacked MAP line" is not a lot to work with.