Hello all, I bought another 7.3 yesterday. It was my sisters that her ex-husband rebuilt. It was a complete rebuild, bored out, new Pistons, rings, valves, etc. but we have run into some running issues. It has rosewood 100 horse injectors in it, 17* HPOP, heavy pushrods, but stock fuel pump. And my last 7.3 had rosewood injectors in it. We have noticed a pattern with RPM surges from about 550-600 when warm and surges all the time. But also have noticed one injector not working correctly. Down the highway it runs fine but idling or just puttin around the yard at low speeds and power, it still misses. It has brand new ford UVCH's on it and plugs. I'm not sure what my problems have been. Maybe I'm just not the best mechanic! But what do you all suggest it could be? Any ideas are helpful. It is a 96 with a 5 speed. Extended cab short box. Has 198k on it. She's rusted out but interior is real nice. I have tried IDMs from other 7.3's of the same year and a 97 and nothing changes. All sensors are ford brand new also. I mean she new and rebuilt. We have put about 3,000 miles on it since she was done and it has ran like this ever since. Thanks you guys!

 

Also forgot that the UVCHs were switched to single plug ones instead of dual. But I'm going to switch them back to dual. Some glow plugs were shorted out.

 

How did the glow plugs shorting out happen? Have you ohmed the injectors thru the wiring plugs to see if all is ok there? Unless you have a good reason to switch to dual plugs, the single SD plugs are better, the glow plug wiring uses a heavier gauge wire. Lots of us have switched to the single ones.

 

Well when he put them over to the singles, it's just you can hear and see the wires contacting each other when I turn the key on. That's what I meant about the glow plugs shorting. When I play with the wires while it's running I can cut one side of the engine off. I can hear injectors trying to fire when I move the wires. It's a mess! Hit a big bump and you'll be down to 4 cylinders ha. Some wires were covered well and others don't have shrink wrap. I'm guessing that's the problem. I'll have to see exactly which wires are doing what and go from there. Maybe it's just the wires making it run goofy.

 

They should have shrink wrap. I had a cutting out problem and I removed the valve cover and cleaned the inside plug and outside plug and then made sure it was plugged in all the way. I would stick with the one plug set up!

 

I also have a problem with cutting out. Randomly does it on the highway and hitting bumps. Scares the hell out of a guy at first!

 

Sounds like the majority of your issues go with fixing the pigtails properly. Solder them and use heat shrink insulation on any connection. Use OE parts as well. not the garbage doorman chit that can be crap right out of the box.