Help Needed 7.3L mystery

[Pecoy]

Needing some help with a little issue. This is my first time to post here and hoping to get a little advice/help. I have an '03 F-350 with the 7.3L and love the truck except for about the past month is has been giving me fits as far as dieing on me. It only occurs on the intial start up in the morning though. I was reading the post about the CPS failure that is typical in the 7.3L and it sounds a lot like that problem. The only thing is, my mechanic and I have already changed out the cam sensor. Is there something more? A little more of what it is doing: on the inital start up for the day, driving down the road it will lose power and die. Some days I can keep it running if I don't take my foot off the accelerator. After giving the truck a little time (30 seconds to one minute) it will crank up and run just fine the rest of the day. Some days it will throw a code and some days it will not have a code. Also, a lot of the times when it does this it sounds as if a fuse is trying to catch a connection in the fuse panel under the steering column. Thanks.

 

[DaveBen]

Pecoy. What code? These computer controlled engines give us a code, if we read at it.

Dave

 

[Pecoy]

That has been the real mystery too. The codes have been different almost every time. The only consistant code was a P3048 or P0348? I think that is what code it was, do not remember for sure. It was the back pressure code.

 

[dpantazis]

one step at a time.
1. start off with basic diagnostic techniques.

2. you mean the Exhaust Back Pressure control? Search for EBPV here and you will learn much about the valve. could be the tube is plugged. its cleanable.

 

[Pecoy]

We have ran all the diagostics, even running the Ford program. The only interesting part of that is when we ran that program, the Ford program read the truck as being a 2000 7.3L with a manual transmission. When we re-ran the program, at the intitial screen, we told it that the info that it was reading was not that truck that it was an '03. At that time it read the truck properly as an '03 with an automatic transmition. I bought this truck used and when we saw that we thought that a new computer had been installed. Still have not ruled that possiblity out either.

Yes the EBPV code is what keeps coming up. We thought that could be an issue too so took the pipe apart at the valve and it appears to operating correctly too. I do appreciate the info and I will look more into the EBPV. The part of that and all this is that is strange is that it will only happen on the intitial start up of the day. It does not matter how many start ups or even the temperature of the truck/engine after that intitial start up it will not happen again the rest of the day.

 

[iracemine]

OK a quick idea. when it dies and you try to start it up again right away to no avail, does the tachometer move?

 

[Smoky]

Just a SWAG, clean the battery cables and battery post to ensure good electrical connections?

 

[Pecoy]

Once it dies I have discovered that I can't immediately crank it back up. Have to wait 30 seconds to a minute and it will immediately crank. The first time this happened to me I did immediately try to crank it and if I remember correctly the tach did move. Now I have noticed once that when the truck first looses power the tach dropped immediately but popped right back up to where the RPM's were at before loosing power.

We did get a code one time about loose battery connections so the posts and cables have been cleaned up, checked, and tightened. That code has not reappeared again. This code also was not the first time this happened, more along the third time.

 

[iracemine]

Once it dies I have discovered that I can't immediately crank it back up. Have to wait 30 seconds to a minute and it will immediately crank. The first time this happened to me I did immediately try to crank it and if I remember correctly the tach did move. Now I have noticed once that when the truck first looses power the tach dropped immediately but popped right back up to where the RPM's were at before loosing power.

We did get a code one time about loose battery connections so the posts and cables have been cleaned up, checked, and tightened. That code has not reappeared again. This code also was not the first time this happened, more along the third time.

get another cps sensor and chuck it in there just to rule out a bad sensor. Bad new parts happens more than you think.

 

[Pecoy]

I will see about trying the new sensor also. The truck acted up again this morning and based on a lot of what I have read on here and from a lot of what everyone here has been indicating to me I am starting to lean more towards an issue with the EBPV or piping on it. This morning the check engine light kept flashing on and off, the truck never died, but as I was driving down the road the truck would have a slight "buck" as if it was not getting enough fuel or the engine was starved for air. Any thoughts?