UVC harness symptoms?
I have a question..(many actually but for now maybe just one or two will suffice) Although this E550 beastie of mine runs better, its still not up to par, dogs big time going up hill..and sometimes on the level when it shifts early, and I still get lousy mileage. Now being a heavy beast, I don't expect to see 15-18 MPG..thats just not realistic, and I can understand dogging a bit on the hills, but not to the degree she does. Symptom #1, many times she'll shift on up into O/D too early and dog WAY down, missing, sputtering and nearly shaking herself apart(figuratively speaking). If I hit the O/D switch and turn it off, she acts like she drops 2 gears and a couple of seconds later picks one back up and runs like a champ...unless I hit high RPMs (around 2800) then she starts to shake and miss again, or at least it feels like she's missing. Mind you the only time I hit those RPMs is pulling a hill down-shifted. I'm wondering as to the most probable cause. I'm really hoping its not the tranny because right now I don't have the funds to fix it, and she seems to shift perfectly all the other times. I keep reading about the UVC (Under Valve Cover harness I assume) coming unplugged, shorting out and/or otherwise going south for the duration. To my knowledge, no codes are being thrown and no SES light is coming on...she just runs like schyt under these conditions. This started after Allegheny Ford said a chip and the PCM was the cause of all my problems and replaced the PCM (which of course was NOT causing my problems-which has now been fixed, thanks to Scott Whisenhunt (HA..I spelled it right this time Scott!)) The fact that it started after they "fixed" the PCM lends me to believe it may be something electrical in nature that got knocked or pulled loose, either by accident (or not)..hence perhaps the UVC harness, although, even though the HPOP read as good with the dead-head test, the "parts replacer"(I won't give him the honor of being called a mechanic) still said it was the HPOP, which they'd happily replace for me...(I bet they would!) With all the combined knowledge and skill here, I'd bet money that you guys will tell it as it is and lead me down that path of Powerstroke Rightiousness. Thanks guys.
Last edited by howardtm; 04-05-2007 at 01:16 PM.