I am looking at a truck that has an odd no start issue.

If you pull the nose of the truck uphill at all.... no start. Immediately roll it back to level ground, she fires right up like nothing is wrong. Difference in elevation is 6-8" and literally 2 seconds after no start cranking.


Things I know.

New lift pump
Shutdown solenoid has power while cranking (no start situation)
Doesn't matter if tank is full or empty


It has me stumped. Any ideas?


Mark

 

My guess would be something in the filter acting as a shutoff when pointing uphill. Could be something in the tank as well but don't think that would react that fast. Once it is running will it go up hill.
It could be the FSS is starting to go bad and the magnet isn't strong enough to push the rod uphill.
We had a similar problem in a car dealership I worked in years ago. Brand new Lincoln Towncar and it would randomly not start. Changed filters, pump etc and couldn't find the problem so finally pulled the tank and found a sponge like ball of something that was plugging the pickup on occasion. No idea what it was at the time but the mechanic left it on his bench overnight and by morning it had gone from 2" diameter to 1/4" diameter and then appeared to be silicone or something similar that reacted with the gas in the tank.

 

Put a fuel pressure gauge on it. Then crack injector lines to see if you have air getting in the lines...

 

Kids toy, only it's supposed to be put in water.

 

Air leak in the fuel lines.

Sent from my HD2 using Tapatalk

 

What year and any mods would be some help.

 

box stock 92 4x4 extended cab w/getrag and plow mount.

I am leaning away from air in lines simply because you lift front of truck 6-8" it wont fire. Crank on it for how ever long you like, no go. Let it down and it will IMMEDIATELY fire up like nothing ever happened.

I am unsure of fuel pressure. When I cracked the feed line into the injector pump and ran the lift pump lever I had lots of fuel. This lift pump is a year old.

This truck will run up a very steep hill without stalling out. He can set at idle for as long as he likes with the nose pointed uphill. Just cannot shut it off. The problem is repeated on command. Just raise the front of the truck 6-8" and she's done.

Wannadiesel... would air leaking into the fuel lines make it not start headed uphill and immediately start once back on level ground? This truck has the plastic snap on line to the lift pump. Where would I even begin to look?

Thanks for the help guys. I have checked the connections, but they feel tight. If needed I will investigate further.... just dont want to get this guy in the shop chasing demons @ shop rate.


Thanks again
Mark

 

Mine used to do that , after a fuel screw adjustment it never seemed to happen again, not saying that's what fixed it or that it will fix yours , its something to consider. Another problem I had was in hot weather my idle would drop. That problem seemed to go away also, sigh of a weak injection pump I've been told.

 

I would try the lever on the fuel pump first prime system and see if it starts. Then if that doesn't work try the mechanical shutdown on injection pump make sure lever hasn't shifted on you for fuel shut down. Make sure you have power to fuel solenoid valve.

 

I have noticed these pumps sometimes idle low when started on a hill. I spent 400 bucks redoing my whole fuel system with -8 pushlock and aeroquip line searching for leaks because thats the only answer i got, and it still does the same thing. Sounds to me like you got a bad one (pump), unfortunately i dont have an answer that i know for sure...