For the last month I have been having issues. It started with the truck dying every 30-45 seconds on my wife. Once she got it home, I ran a scan tool on it, found a bad CPS, which I replaced. However, that did not solve the problem. 14 out of 15 times, the truck runs just fine. Out of the remaining times, it cuts out (misfires) for my 15 minute drive to work and about once a week, it just won't start. Most of the time it runs perfectly fine once the scan tool is hooked up and monitoring it. Today, I was able to get some preliminary readings before it decided to run normally. The buzz test went as it was supposed to. No codes KOEO, and since I couldn't get it to start, I couldn't do a KOER test. I was getting (while cranking) a fuelpw signal of 0.000, ICP reading of 0, the IPRDC was 54%. And when I went to check the VPWR and the RPM readings, the truck started just fine, with all readings returning to normal.

The truck is a 1996 F-350, 2wd, auto, and 274k miles. The EBP has been gutted and the exhaust has been replaced with a down pipe back system, other than that, it has no mods. Recently (within the last 18 months), I have replaced the IPR (remanufactured, and it would stick once the truck fully warmed up), the fuel lift pump (it was leaking), the IDM (it failed, and I replaced it with one from a junk yard), the CPS (as mentioned above, I had a trouble code for that one), and the ICP sensor, as it was leaking oil through it. I have changed the HPOP oil this week just to make sure that wasn't the problem (it had been 8,000 miles since the last change, I change it every 10k), and the oil was changed a hair under 3k miles ago.

Most of the time that it is giving me an issue, it is late in the afternoon and hot (+95*). So it isn't an issue with the glow plug system. There is no sign of a high pressure oil leak, either internally or externally.

This truck is starting to frustrate me, mostly because I can't find the problem. Does anyone have any ideas to help me fix this or at least find my problem?

 

Couple of questions: where did you buy the CPS? Parts store ones can be bad right out of the box. Use genuine international (pry the cheapest as well) or ford CPS only.

Also when you crank is there any smoke out the back?

I'm sure someone with more wisdom than I will chime in here soon.

 

When it won't start, no smoke at all, even when it starts. When it's misfiring it will puff white with blue tint smoke in coordination with the misses. I bought the CPS at O'Reillys

 

Get a CPS from Ford or IH and then go from there.

 

Previously, when it wouldn't start, I still got a RPM reading of 400+ during cranking. I just did not make it to that reading before the truck started this time. I'm reluctant to throw parts at the truck and see what'll fix it

 

The CPS is something you need to get from Ford or IH anyway. The parts store ones will not last long at all. I would just go ahead and get that out of the way and if it doesn't fix it, then you eliminate that from the problem.

 

My wife is picking one up from Ford right now

 

While you're under the hood, I would also check the wire connections to the sensors. Intermittent problems like you described could be caused by a bad connection. My work truck was having similar problems. The shop found a poor connection to the ICP. They cleaned the contacts and put a little dilectric grease in there and fixed it.

 

So...when cranking..icp is zilch but ipr duty was 54%···
need 500psi to make the inj work...reman ipr?.....
Am i the only one that thinks that all is suspect...

 

The thought crossed my mind as well, definatly something to check.

 

I've seen the IPR at 54% before, but this is the first time I've seen ICP at 0. I'm going to check the electrical connections on the ICP (since its much harder to check the IPR connections). I did recently (1-2 weeks ago) verify that the stamped nut on the back of the IPR was tight (and it was tight)

 

When the IPR failed before, after the engine fully warmed up (15-20 min of driving), the engine just shutdown and would not restart for 30-45 min when the engine cooled down some. I'm not getting symptoms like this now, I drive about 25 min to work everyday and 70 miles each way to my property a couple of times a month.

What other symptoms does a failing IPR have? And is there anyway to diagnose it other than replace it and see what happens?

I keep thinking that I have fixed the current problem because for 3-5 days, it doesn't come back. The truck will run fine for a few days, then start misfiring for 1 or 2 trips to work, home, or the store. Then it won't start after the engine has completely cooled down and I try to start it in mid-afternoon when I head to work. And somewhere later (maybe 15 minutes, maybe an hour) it starts like nothing was ever wrong.

 

I believe there is a way to pull the ipr out and clean it. As to how I'm not sure. I know one of these other guys know though!

 

I recently pulled the IPR and cleaned it. I didn't have new seals but I cleaned it up and no change

 

I changed the CPS the one from Ford. Truck still misfires and had a very long crank to start when I left work.