Hey guys, Need your help. I have a 2000 exc 7.3. Injector harnesses were replaced around 2 yrs ago, glow plug relay at the same time, CPS, changed glow plugs dwn the driverside bank around the same time. Then last fall I started getting service engine light. Ran the codes and its all the glow plugs dwn the pass. side. Figured theres no way they all went bad at the same time so just kept it plugged in all winter and I would get to it when it warmed up. WELL NOW ITS HOT OUT! And its started doing even more things so where do I even start? When I start it up, 50% of the time it lopes like it did when the injector harness went out. I can lay my foot on the peddle and it usually smoothes back out. If I dont let it sit and warm up to op. temp and take off then about a 1/4 mile dwn the rd it will act like it ran out of fuel. Sometimes even shuts off. IF it doesnt shut off after about a half a mile it will take back off and run fine. When I stop at a red light you can feel a slight miss. Most of the time when it is warmed up and has been running for a while it runs fine and no problems. PLEASE HELP. Its a daily driver and I need to get it fixed asap before I tear something else up. Oh, whats the 50 cent upgrade? I tried searching it and just saw where people did it but couldnt find what it was.

 

Check the harness again. Sounds like you have a melted connector... By your comments I will assume you have the GPCM and not a GPR, so check the plugs there, they will cause hard start issues as well.

I am replacing my wifes Excursion wire harness and PCM to get away from the GPCM...

 

It sure sounds like the UVCH.Check this thread out.


https://www.ford-trucks.com/forums/9...rpms-long.html

 

I believe Payson PSD also diagnosed a similar issue with a burnt center pin on the UVCH. Will try to fid the link on that one, but it is something that may contribute to one side being out, certainly worth a look.

 

mine had hard starts at 100*F when the uvch had come unplugged on the DS.

 

Ok. Got out there for a quick look yesterday. Only had 15 mins. to play with it. I did notice the center pin had a S bend in it and it was bent below the other wires. I pulled it up to the top und tried to make sure it was making a good connection. Erased the codes, and drove it around 120 miles. I did shut it off several times (between 10-20 times) ran great. No codes. But I knew the test would be this morning when it was cooled off completely. My wife drove it today and now the codes are back. She didnt know when they came back on but I beleave you guys are right. I will get back out there and give it a closer look and check for frays. Just wanted to update you on it. Try to do the 50 cent upgrade at the same time. Oh I dont have a clue what a GCPM is. If thats stock I got it! What is the GPR and PCM?

 

GPCM- Glow Plug Control Module
GPR- Glow Plug Relay
PCM- Power Control Module

 

Oh ok. No I have the relay. Replaced it the same time as the glow plugs.

 

If you have the relay then how would you know the passanger side glow plugs were out? The only way to tell this is with the GPCM?

I still believe you have a UVC issue.

 

Sorry its took so long to get back. If I told you wrong its because I dont know what Im talking about. Im learning as I go. I used a code reader to see what glow plugs it was. I did change the relay around the same time like I said. I checked both sides of the wiring harness to make sure there wasnt any bare spots. I checked the post. There wasnt any burnt. They are seated. Still doing it. It has got a worse miss now. It isnt clearing up at high speeds. I saw that Advance Auto has Dorman UVWH for $23. Has anybody used them? Good? Bad? If they are ok then Im goin to get them and do the 50 cent upgrade at the same time. Figure Im under there might as well put new 1s on. Thoughts? Thanks for all the help.

 

I have used the NAPA equivalent for the UVCH and they are a tighter fit, I also used the local international dealer for the gaskets. There was probably not a need for the quarters, but since I had them in the old ones I reinstalled. When I swapped my motor however I bought new harnesses, so I did not run the aftermarket for very long to thoroughly test.

Clay sells the Motorcraft Valve cover gaskets at a great price if you wanted those too, since they are a culprit Ford Valve Cover Gaskets

 

Ok. Updating my problems. I got out there last wknd and put a new UVCH on. I did the 50 cent upgrade with the swap. Well 25 cents worth. I went to do the other side and that harness had a suport in it so the quarter wouldnt fit on it. That side was not the problem side anyway. Just making sure it wouldnt be later. I erased the codes with my code reader. I did figure out what the "miss" was. My oil level was low. I did a oil change and it is running smooth again. It hasnt shut dwn or acted like it was running out of fuel anymore. It has never used oil before or doesnt have any noticeable leaks so that is something I will have to keep a eye on now. I do still have a problem tho. I started it back up the next morning after erasing the codes, new uvch, and oil change and the codes are still coming back. They are the ones I replaced last yr. They are autolites. Codes are still the same glow plugs 2-4-6-8. I can erase them after the truck has warmed up, drive it all day, and they dont return until the engine has sit all nite and cooled. Ideas on what else it could be? I had a guy tell me it may be the ECU. Thoughts on that? Thanks for the help.