Hello,

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?

Any ideas??


Thanks,
Mark


EDIT: I'm afraid that I've posted this in the wrong part of the forum. If I did, please remove this message, because I already posted the same thing in the other sub-forum.

 

Sounds like glow plugs to me and with a no start I would be leaning more towards the glow plug relay. If you have the two identical relays under the hood (some years don't) you can just swap them with each other.

GPR in the pic:

 

Thanks, but I already tested the relay and even bypassed it giving current to the gp's straight from the batteries, just to be sure. And all gp's have already been replaced.

 

I' think I found the (or at least a) problem. I've looked at your picture again and I noticed something:

I think that the relays are wired the wrong way. I went to the truck to be sure and measured the signal wire(*) on the relay and it gives ZERO volts when I get the wait to start light, but when I measure the signal wire(*) of the air intake heater, I get 13 volts. Now, I assume that the air intake heater shouldn't be heating before the engine is running... And that the glow plugs should be working BEFORE the engine is running?!

Long story short: I think that the signal wires(*) have been mixed up by one of the previous owners.

(*) Is that the correct description? If no, by that I mean the small wire that "tells" the relay to close.

I must have been fooling around at the wrong relay while measuring in the past...

 

for one a 7.3 diesel even at high 30 degree weather will start hard, and at 28 degree's not being plugged in your lucky it even started at all. Are you throwing any codes? Did you replace parts just because or did you check them and they were all bad?

 

intake heater is a useless piece of junk, tons of people have it removed for better airflow, including my dads 2000 F350 and his truck starts in below freezing weather ever winter, it is plugged in though

 

this might be a dumb question but when was the last time the fuel filter was changed and when the bowl was cleaned out? and do you use a fuel conditioner??

 

Mostly I replaced based on codes, except for the starter.

I don't remember the code, but I still get one for the air intake heater. Does anyone know what triggers this code to be set?

Previously I got many codes, among them are HP oil pressure (replaced IPR), P1316 (replaced valve cover gaskets with harness after one disconnected on its own), the cylinder contribution test gave two bad cylinders (#3 and #8?) which lead me to place a Delphi CPS based on many forum posts. There was another code which came together with the P1316, but I don't remember the code and can only say that it had something to do with the automatic transmission. That's gone for now, but I'll have it checked out in January anyway. I also know that I was driving in heavy rain when the tranny code came on. The "overdrive off" light was blinking. I didn't have it again since then.

The truck has had a full service when I bought it - all new fluids, all new filters and so on. It had problems before and after and now it still has problems. What I don't know is if the bowl has been cleaned out, but the thing is that once the engine runs and is heated up a little, all problems go away. If it would have a bad filter and/or fuel bowl, it would stay that way once warm, IMO. Or am I wrong about that?


Thanks again,
Mark

 

I have a E99 F350 PSD and my problems sound a lot like yours.

After replacing the IDM, the PCM, the CPS, the HPOP, installing rebuild injectors, dropping the fuel tank and doing the Harpoon and the Hutch mod, replacing the fuel pump, cleaning the fuel bowl, replacing the filter and replacing the fuel heater plus replacing the ICS and oil pressure regulator on the HPOP (can't remember its name) I thought I had it fixed.

then cold weather came and the problem returned. Had it towed to repair shop and they wanted to start replacing injectors and I had them push it out side and forget it.

there it sets until I finish this work shift and get a trailer and haul it home.

The mechanic tells me that the #3 and #8 injector show bad on his analyzer. Exactly what I was told before I replaced all the injectors.

I believe it is something in the wiring such as a pin that does not make good contact when it is cold because it shrinks in the connector.

Hope you find and answer that I can copy.

I have four weeks before I finish this work shift and can do anything with the truck.

Will monitor your progres, please keep posting.