I've been reading and learned a lot on this forum, but my problem stays. It's a long post to be sure I give all info.
A little history:
I bought a 2001 7.3 PSD in 2011 with 150k miles on it which sometimes had problems starting, mostly when it was cold (40°F or 5°C). Sometimes it ran rough, other times it ran perfectly. The rough running increased in frequency until this summer, when it ran roughly all the time. (feels like on 7 cylinders) By roughly I mean there's a vibration through the whole truck body.
Since I've bought it, I had the starter replaced with a denso starter because it was turning over very slowly, replaced the IPR, replaced all glow plugs, replaced both batteries and replaced the CPS with a black Delphi.
A month ago I was driving along the hi-way and began to run on 4 cylinders instead of 8. Then I've had the UVCH replaced together with the valve cover gaskets. The UVCH and gaskets are one piece now, so they can't get disconnected anymore.
Now all these things have been replaced and again it sometimes runs perfectly, but runs rough when starting with a cold engine and now it's 28°F (-2°C) and doesn't even start at all. It does blow white smoke from the exhaust, but that's after more than 10 seconds of cranking.
Since it's only when it's cold (all things being relative), I would assume it has nothing to do with wiring, but more with the electronics inside the IDM that's going bad? Can the IDM go bad when the UVCH is not well connected?
I've been reading hundreds of posts about bad starting, running rough and missing and I always read the same answers and I think I've replaced just about everything that's been suggested, but my problem doesn't seem to go away. There are 2 things that were not replaced yet: the IDM and the injectors.
Last edited by Mark_be; 12-13-2012 at 05:41 AM.