Ok, I need help. We have a 1999 F-350 at our shop right now. I cannot figure this thing out. It came in cranks won't start. I check the oil first...good. I checked for codes, found some, tracked them down with breakout box, etc., etc. found the PCM to be bad, That was coincidental. Still no go. Can get it to start with ether. Checked IDM with another truck we had at the shop, still no change. Checked cam sensor...good. Checked ICP, found low readings. Checked around, tracked it down to either IPR, or High Pressur Oil Pump, changed both. Now have less pressure than before on the ICP reading. While cranking (batteries good, and battery booster hooked up to each battery) only getting around 140 PSI. Ether, and she starts, and will now idle, where it wouldn't even do that before. What the heck else could it be? I had 400 PSI while cranking at one point, but now I can't get passed 140. I don't where else to look. Could th O-rings really bleed of that much pressure? I called our local ford garage, and they didn't seem to think that the O-rings would blled of that bad that it should create that much of a drop in pressure. What else should I check. I mean, we've already done a $400 computer (it WAS bad), a $700 HPOP, a $300 IPR, what next? I hate these things.

 

Truck unplugging the ICP sensor on top of the driver's side oil rail. It's located just behind the alternator. If you unplug the electrical harness from it, the PCM will load default values and "guess" the oil pressure. If the truck starts and runs fine with the ICP sensor unplugged, then you found the problem.

If it still doesn't start, check for a leakdown issue. Since it's not building oil pressure during cranking, before you crank, open up the peep hole on top of the HPOP reservoir. The oil level should be within an inch from the top. If the oil level is low, then you have a leakdown, probably from a bad check valve.

 

Curtis, I just going to throw this out there because this is beyond my knowledge. Would the UVCH have anything to do with these symptoms?

 

I'll check the ICP tomorrow. I asked the Ford guy about that, knowing that it would set default values, but I completely spaced unplugging it. What's a UVCH? I know the fuel pressure is good, and know the problem is in the pressurizing of the heads, but can't track the dang thing down. I'll do the ICP, and then pray that it starts.

 

Under Valve Cover Harness--several wires that go to glow plugs and injectors.

 

Not usually. The HPOP will still build pressure, but the injectors will not receive the signal to fire if the UVC's are unplugged.

One thing I did forget to ask... What is the duty cycle as you crank? Does it continue to rise all the way up to 64%?