Hi i have a big problem. I was drivimg my truck and it just started running really rough. I broke into it today and found that my injector\glow harness had burnt out on one termnal. so i spliced into it with anew one and started it up. it ran fine but then started running like crap again. so then i pulled it off and saw that it started to burn it again. so i pulled the valve cover off and looked at the harness on the inside and it was burnt in the same spot as the one leading into the gasket. i traced it to the glow plug wire (the black wire) i dont know what is causing it to burn out. Could a bad glow plug do this? O i also noticed on the other harness the same wire is burnt.(under the same cover) please any help would be much apperciated.

 

May be this will provide some kind of help

http://www.forddoctorsdts.com/articl...icle-05-10.php

 

Had the same problem. Had 2 harnesses go at the same time. Turned out 4 out of 8 glow plugs were bad. Replaced them and the harnesses. Everything's been fine for 300 miles so far.

 

Ok thanks for the tips i just ordered a v\c gasket,two harnesses,repair harness kit, and8 glow plugs. So the glow plugs went bad and caused the harness to burn up?

 

That's what one of my friends told me. He said that bad glow plugs will eventually cause the harness to burn out. He also said if not fixed the problem gets worse and eventually burns out the main harness. He works at the local Ford Dealership as a diesel mechanic. It's been real nice to have a friend that works on Powerstrokes all day.

 

Also he said to not ever use Autolite glow plugs. They like to break off which means you'll have to end up pulling the heads in order to get them out.

 

This is from Racer_X ...:


Excess resistance in the circuit is what causes it to burn the harness. Wiring is to small to handle the heat when the plug doesn't use the amps up to heat the tip. Heres a simple explanation:

Ford/Nav VC gasket/harness was redesigned with better conductors several years ago. Here's a basic way to explain it without math at all:

If the glow plug (load) were to short, the burn or weld will happen at the point the short occurs. If you use a welder it welds at the electrode (load). It won't burn up your weld cables.

So why does the harness connector melt? Excessive Resistance causes heat. A GP has little resistance or ohms. It's nearly full power that warms the tip using up power to make heat. What little power isn't used returns thru ground to battery completing the circuit. Excess resistance or poor conduction from green stuff or corrosion prevents full power from flowing to the load (glow plug). The wiring gets hot and melts because you still have a complete circuit back to battery ground, but no load to use the power up and keep the wiring cool as power flows thru it.

Now think of the welder again. What happens if you forget to put a ground clamp on the metal to be welded and touch the electrode (load) to the metal? Nothing. The circuit is not complete, so no power flows at all. No weld or short.

Best way to prevent the burned wiring is a good conductor to your GP's. I pack Di grease in all underhood connectors. The best way to keep the connection moisture free and clean is silicone dielectric.

If your harness burn't from the GP connector back, then you may have a shorted plug. Ohm it, compared to the others. If it ohms out higher than the rest it's also BAD. The extra resistance is inside the plug, not allowing full power to the tip.
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ok i checked my gp and found that six of them were bad. and i also found an extra on wedged between a valve spring on the passenger side. it didnt appear to cause any damage. All i need now is my injector\gp harness to come in so i can see if she fires up. fingers crossed

 

okay i put it all together and she still ran like crap. WTF? so i figured it could possibly be fuel pump because i noticed it had a leak anyway. so i replaced that and it still ran really rough. i pulled out the brand new fuel filter and noticed that it was covered particles of something. then i drained all of the fuel out of the filter housing and flushed it with fresh diesel and let it run for about four hours. it runs like it used to now. but it has a miner shake when i let off the gas. so i wsa wondering if a sensor could be bad such as ipr or maybe a pressure regulator?

 

Get it on a scanner & read ICP pressures & IPR DC% ....



Is it hot or cold?...

 

This might be out there but have you replaced your CPS lately. Mine seemed to smooth out some after I replaced that.

 

Whats a CPS? and how much do they usually run?

 

Cam postition sensor. $15


http://catalog.powerstrokeshop.com/p...&subcat2=86772

 

Its worth a shot I guess. How violent is this shake when you let off the throttle? Are you sure it's not the drivetrain?

 

its not to bad but its noticable. i noticed it did it a LITTLE MORE WHEN I WAS PLAYING AROUND with the burnt wireing harness. but the weird thing is it doesnt do it all of the time.