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Discussion Starter · #1 ·
I picked up a 1999 F-550 7.3 auto at auction a couple weeks ago. It was running slightly rough when I got it which i just figured was a stopped up fuel filter or old fuel as it had been sitting for a while. There is no smoke or unusual blow by. Changed the filter and drained/replaced the fuel and drove it about 25 miles with no change. After doing some research I decided that the UVCH was the place to start. I pulled the valve covers and put my multimeter to work. The common ground on both sides had resistance and all injector solenoids were under 3 ohms so i replaced both gasket harnesses with no improvement. I then found where the external plug for the driver side UVCH had a couple bare wires that looked like they might be rubbing. I replaced this plug and the truck wouldnt start on the first try. I finally got it started and it runs like total crap now. I double checked to make sure i had the corresponding wires connected correctly and everything looks right. The CEL is on now (it wasnt before) throwing lots of strange codes. I am going to replace that plug again Monday because it is Dorman instead of FoMoCo and might be defective, but looking for more theories?? Any help is greatly appreciated.
 

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Discussion Starter · #2 ·
F-550 7.3 issues

Also, I checked the ICP and the plug was oil free.... I need the truck running good before we start baling hay soon so any ideas would help.
 

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what are the code you are getting? what scanner are you using? what mileage on the truck? maybe look at the IPR tin nut, make sure its tight.
 

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Junk dorman parts is the issue here.

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Discussion Starter · #5 ·
F-550 7.3 Issues

I am using my Insight off my other truck to scan with. Not the best but it's all I've got. I'll have to run them again when I get back to the truck, I forgot to write them down. It has 247k on it. I have not tried the IPR nut but I will when I get home. I am going to replace that pigtail with a Ford part first thing though. Is there any chance it could be an IDM issue?
 

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Codes are the best place to start the repair process. Pigtail may be the problem but i would start with codes first. At those miles it could be injectors. Search here to find out how to OHM harness from IDM to injectors. Super easy. Fire her up with valve covers off to see which injectors are not spitting oil or are leaking oil at base. Welcome to the forum, you will find lots of info and help from great people here.
 

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Discussion Starter · #7 ·
Thanks for the help, I'll be pulling the codes again when I get off work today. Going to stop by the Ford dealer to pick up the pigtail that I ordered and I'll post an update after I mark that off the list.
 
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