so ive had this truck for about say 6 months I think about 20k miles so far. first month was collapsed fuel lines and then I overheated it being a dummy and had to put new cylinder heads on. and right after that when it started snowing a phantom problem showed up. when you hit just the right bumps it will trip the service throttle soon light the check engine light and the check gauges light and the engine will either chop to an idle or die. it gets way worce when you've busted through some snow drifts or if you take the truck swimming itl get real bad where eventually if you get her wet enough the lights stay on and the glow plugs wont cycle and it just cranks away. if you let it sit long enough itl start but then die at every bump. if shes dry itl be peachy till you hit just the right bump itl idle down or die. starts right back up.


now its been doing this for quite a while now its had a new fsd put on it not long ago and its still doing it iv visually checked everything I can but nothing it seems to be bad wiring somewhere. im suspecting the ip harness but when you get the bottom of the truck wet and it goes ape **** on me the top of the engine is still dry. ... idk what to do you cant take it off the road anymore

lift pump pressure is at 4 psi wot 5 idle
the shutdown solenoid went bad and has been clipped and reinstalled.
I thought when I did that it may fix the problem but I thought I wasn't gonna be able to shut it off. but I found out the stepper motor in the pump will cut it off so ive never replaced it yet I don't know if that's bad or not I don't see why It would hurt anything. and with all the lights comeing on when this happens I cant believe its the ip itself.

 

Any codes?
How do you use the paper clip for the obd1

 

yea that's the darndest thing to, it NEVER throws any codes. ive actually got the little key fork to read them obd1 is flash codes only I believe could be wrong tho.

the only code ive ever seen this truck give me is for the transmission ratio undefined and you have to run WOT through 2nd gear and itl throw that but hasn't been a problem lately.

unless ive tripped the undefined transmission ratio all I ever get is the validity code 12

 

Get all the grounds cleaned and tightened.

 

there is a ground strap daisy chain from firewall to cyl head to truck frame all good. fsd has good ground to ip battery grounds are on the drivers side intake manifold and the back of the starter motor those are good. idk maybe im missing something seems logical that I could be loosing ground to the ecm but I don't know where that grounds to. the electrical diagrams in the clymers manual aren't always that helpful

 

ECM grounds are usually located behind the intake on a water block off plate stud on the passenger side-you note grounds on the drivers side where the glow relay is normally found?

 

no I got studs in the coolant crossover and one of my battery grounds goes to that and yes I believe I know of the ecm ground of which you speak its a black wire with a ring terminal going to the same stud on that block off plate as all the other ones but its the only one that's a wire and not a web style strap these I know are clean and good

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i wont lie to you i think it may have started after i put the new cylinder heads on i just don't know what elce to check

 

Should be 3 grounds on that stud,IIRC 1 wire on it's own ring terminal and 2 wires share a ring terminal.

 

if the ecm was loosing its ground then i shouldn't be getting those dummy lights coming on when it stalls am i correct in this thought

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ill have to look again tomorrow morning now im not sure

 

I would say you are just getting the bulb check lights when it stalls just like starting for the first start of the day.

Could be more like you are losing ECM power from corrosion at the underhood bower distribution block or ignition switch?