There's a little Amish in all of us....

Dorman UVCH/gasket products are known for problems. Those are rather strange conditions, but the injector and GP circuits run right next to each other through those wires / connectors, so they're naturally a suspect. Not sure where to tell you to look next, other than damaged terminals as mentioned. If it were miswired, as has been reported about the Dorman products, you'd have problems 24/7.

 

The situation is worsening. I ran it a few days with the little wires from the GPR off and it was fine. Ran good and everything. But those days are over! CEL is on as soon as the GPR cycles off. Feels like I am running on 4 or 6 cylinders. Voltmeter dips up and down some of the time at idle - just like a wiggle really. Not much movement, kind of like something cycling off and on. It's in the driveway now until I can figure it out. I replaced the CPS just in case and no change. I have no idea about the IDM but am going to go and try to figure out where it is and what is does.

The pins on the UVCH look fine on the outside, so if there is anything it would have to be inside which doesn't make much sense to me. Still getting the P0470 code. Anyone think I should pay the $90 and replace that sensor?

Any ideas appreciated.

 

IDM is on the drivers side inner fender, rectangle box. Does it ever quit on you, or just running bad? Does it run bad all the time?

 

Only runs bad when the GPR cycles off. With GPR small wires disconnected I have 12v from ignition and 1.379volts from the PCM - that seems weird, right? Is that normal? Doesn't seem like I should have voltage coming from the PCM like that when the GPR timer has cycled off. When the timer is still on that wire only shows 0.024 volts. I don't understand where that voltage is coming from at all - any guidance appreciated.

 

Don't mean to leave you Dan, but I follow your statement earlier. Electrical and me don't mix very good. I haven't had time to look at all your thread, but I will later and help IF I can.

 

Thanks. I totally understand. I just have no clue where to go next.

 

I've been reading alone too Dan and I'm baffled!

 

I talked to Aaron and he suggested disconnecting the UVCH pigtail while it is running crappy and see if I can isolate where. He thinks I have a short from the GP to the Injector pins there. It sounds like the back 2 cylinders on the passenger side are knocking like crazy when it happens so I am hopeful that is all it is. Won't get to check it until tomorrow. Thank goodness it is warmer and I can ride the Harley!

 

That is what I was thinking too.

 

Does anyone have a good wiring diagram link though? 1996 F350 4x4

 

I really do think your VC or UVCH are shorting out. Ohm out the pins to eliminate that option completely.

Have you tried to start it on a warm morning without the GPR connected?

 

There isn't "a" diagram. It's a whole book. Called the EVTM - Electrical and Vacuum Troubleshooting Manual. Used ones come up fairly often on eBay, anywhere from $15 to $40. Worth every penny.

 

Just an update for those following:

Truck is killing me! lol
Went out yesterday to try and start it so I could pull the connectors at the valve cover and see if it made any difference. No fuel pressure and batteries low. Put it on the charger and then today gave it a go. Still no fuel pressure. Went under and jumped across the oil pressure switch and got pressure (there was a hissing sound in the valley area and the pump was putting out 60 psi on my pressure regulator - not sure if that is just extra pressure bleeding off or some OTHER problem).

Truck started and same thing. Ran ok until GPR cycled off then like crap. I held that pedal around 1500 rpm and let it run a while to warm up. Once i let off it idled but really rough. Pulled the pigtails connectors on the passenger side and it killed the engine. Restarted. Pulled them on the driver's side and no difference! So, it seems the drivers side bank is not working.

Bill suggested I pull the IDM which I did and there was no water in it that I could tell. So, I am going to pull the valve cover tomorrow when it quits raining and see if I can find something in there. Bill said the IDM will shut down a bank if there is an electrical problem, so who knows.

Until tomorrow....

 

Wait, wait, oil pressure switch?.... Are you running e-fuel?

 

Yes and it seems to be fine.