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Engine is running rough

2K views 9 replies 4 participants last post by  freakyjlh 
#1 ·
I bought my first powerstroke diesel(95 f250) about two years ago and haven't had any problems with it till now. I keep up on all the preventative maintenance that diesels are supposed to have, but now something happened and i have no idea where to start. every now and then the truck will start shaking and running very rough(seems like it is misfiring)and the check engine light will come on. it will run like this for a minute or two then stops and run perfectly fine and the CEL will turn off. the other day it started running like that again only it never went back to running like it should. i gave it a little bit of throttle and tried driving it around the block a few times but still nothing changed. not too sure what it could be. any suggestions on where to start or what it could be would be appreciated.
 
#2 ·
Check the UVCH connections (undervalvecoverharness). They tend to come out, causing what you are describing. Pull the valvecovers, and make sure they are properly plugged in. Then, do a search for valve cover quarter trick, to make a wedge to prevent it in the future. If the harnesses have been arcing out for a while they may need to be replaced.
 
#3 ·
Knowing what codes are strored would help, but there are a few things you can check:

Check all the wiring connections (there are 4 of them total) at the valvecver gakets (on top) for evidence of melting/burning.

Remove the oil cap and take a sniff. Smell like burned wiring insulation? If so, you may have burned/melted injector wiring harness connections under the valvecovers.

If you feel like it, remove the Injector Driver Modeule (IDM ... the box below the driver's side hood hinge) and see if there is water sloshing around in it.

If all seems good in those departments, post back and we'll look at some other stuff. Cheers!
 
#7 ·
Well, I pony'ed up the cash and ordered my new UVCH's last night. I'm sure that at least on the passenger side they aren't looking so hot since one plug was covered in oil when I pulled it. Then to make matters worse, I broke the retaining clip on a plug from the drivers side. Go figure. I'm gonna try to pull the covers tonight just to get a peak. I will let you know if I get my issue fixed with the new harnesses. Thanks.
 
#9 ·
Replace the valvecover gasket on the affected side(s) or you will be doing it again shortly! You can also get the International external harness repair kit to fix the broken connector shell:

Valve Cover External Harness Repair Kits (contains 4 hard shells w/seals, w/o pins)
(Ford) F7TZ-14489-BA (94-96) w/o pins
(Ford) F7TZ-14489-AA (97) w/o pins
(International) 1830829C91 w/o pins

Cheers!
 
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