My truck: 96 Powerstroke 138k miles only mods downpipe and 6637 ? filter.

Problem: About a month ago the truck started stumbling while going down the road (intermittenly, CEL came on while this happened). It would run like it was down a few cylinders. It would go away when I let off the accelerator. So I changed the oil (due) (Rotella), changed the fuel filter, and changed the CPS (one that was in truck had about 6k miles on it and was in it about 5 months). Replaced it with IH CPS recommend on site. Well it seemed to do the trick. Seemed to run as good as ever. After about 2 weeks it came back again. Had a friend check codes (Snap on scanner) and came up with P0122. I know this is the accelerator position sensor. The next AM I go to start it and it starts and dies (runs less then 20 seconds).

What I've done: My father has a 97 PS so I borrowed his accelerator pedal (no difference, in fact mine works fine in his truck). Checked fuses with test light all seemed fine. Checked fuel bowl (full). Checked HPOP resoviour (sp) (full). Read somewhere possible IDM problems so put dads in with no change.

Suggestions Please......what have I forgotten.

I am thinking of getting another CPS and trying but I would have thought if it was bad it would have showed a code for it.


Thanks,
Paul

 

If its warm where you are , pull the IDM out of the truck & shake it . Might have water in it ..

or ,the under valve cover harness on one side or the other had crapped out of come loose .. when its running bad , unplug the wiring to the valve covers ,one plug at a time . One plug won't make a difference in the way it runs , that is the bad one ...

 

^^^X2 on what Rick said. Mine was having a similar episode and it was the IDM.

 

Already checked IDM, put one from my fathers truck with no difference.

I have not check VC wiring yet.

Thanks for your reply

Paul

 

Paul, sorry must have skipped over that above... UVC would be the next place to check. let us know what you find and we'll continue to help if we can

 

I missed that too...

 

One other thing, as soon as it starts it runs fine for about 10 seconds than it acts like it is down a few cylinders and eventually dies. My question is would it do this if the VC connections were bad? I guess what I am trying to say is I would think it would run like crap at start up if they were bad...

I will try to check them tomarrow.

Thanks again,
Paul

 

If it does that every time , you may have a bad injector solenoid ...



On edit :

That points to the LPOP not being able to keep the oil reservoir full at start up

A cheap test would be to try a synthetic oil ...

 

Update: Went out and disconnected the ICP. Ran fine for about 10 seconds than just shut off. When it is plugged in it runs fine for the 10 seconds than runs a few more with it missing, than shuts off. So with it unplugged it does not miss it just shuts off. Don't know if that means anything......

Any thoughts?

Paul

 

When It dies , look in the HPOP reservoir ,see if its full..

 

Well checked VC connections today. The right rear is melted, so I will get 2 new ones (do the left also) and the glow plugs. Hopefully it will take care of it. Will let you know what happens. It will be a couple weeks. I would have thought it would have still run (badly) without one or two injectors. Any comments would be appreciated.

Paul

 

Update: Replace Valve cover gasket, harness under VC, glowplugs, and burnt harness plug. Truck runs great now. Thanks for your help.

Paul