1fzfe stalling during steep ascents (1 Viewer)

[BILT4ME]

I was thinking possibly a wiring harness short on the fuel pump that only shows up on steep inclined and possibly when the fuel has heated up, causing the wire to drop and ground out.

Could be anywhere on the truck doing the same thing.

I once diagnosed a Chevy S10 that would only die when going slightly uphill on a certain road. Discovered it was an ignition wire at the back of the head that enough incline and temperature to allow it to droop and ground out on the top of the bell housing.

This sounds electrical, not fuel related. But losing the fuel pump may be enough to shut off instantly, not like a plugged filter.

 

[jonheld]

I was thinking possibly a wiring harness short on the fuel pump that only shows up on steep inclined and possibly when the fuel has heated up, causing the wire to drop and ground out.

Could be anywhere on the truck doing the same thing.

I once diagnosed a Chevy S10 that would only die when going slightly uphill on a certain road. Discovered it was an ignition wire at the back of the head that enough incline and temperature to allow it to droop and ground out on the top of the bell housing.

This sounds electrical, not fuel related. But losing the fuel pump may be enough to shut off instantly, not like a plugged filter.

Not likely a short. A short would pop a fuse. I still think it's an intermittent connection. He should play the wiggle wiggle tap tap tug tug game.

 

[SHIfTHEAD]

Not likely a short. A short would pop a fuse. I still think it's an intermittent connection. He should play the wiggle wiggle tap tap tug tug game.

My first stab at this would be checking the connector at the coil, and ensuring it's solid and the contacts inside are tight and clean.

 

[Rusty Marlin]

I'm with @jonheld on this. It's an electrical gremlin.
Now whether its ignition side or fuel pump side, that's the question. Both will instal kill an engine if interupted.

@William839 ,
1) have you added anything to the battery posts or loosened the battery connectors recently for an accesory? (been there, that's why I'm asking).
2) will it instantly restart while on the incline or does the rig have to be level?, nvmnd, you ansered that in post 6. So why won't your brakes hold on a hill? That's terrifying.

 

[use2bn83]

I’ll chuck a couple out there. If these have been mentioned, disregard.

1. Wire harness where it passes by the egr pipe. A short here doesn’t necessarily pop a fuse. It can creat a short that puts the ECU into a fault that instantly shuts it down. It should be visually inspected as wiggling it may not reproduce exactly what’s happening.

2. A cracked intake hose that opens up drastically when everything is loaded down. This usually would cause a hesitation before stalling, but who knows.

3. The bolt is loosening at the cluster of ground wires at the back of the intake manifold.

A diagnostic test to see if it’s engine movement or gravity related may be to power brake the vehicle in low range to simulate high loads.

Good luck!!

 

[80t0ylc]

Yes it does but no codes , one I start the rig it goes away (as it should )

If you get a CEL with no codes, that’s like stalling the engine with a manual transmission. ECU sees no system faults, like it’s operator error. Some electrical faults may not throw a code which kind of points to what we’ve seen with that harness near the EGR. I’d look closely at that. As mentioned, in below quote:

1. Wire harness where it passes by the egr pipe. A short here doesn’t necessarily pop a fuse. It can creat a short that puts the ECU into a fault that instantly shuts it down. It should be visually inspected as wiggling it may not reproduce exactly what’s happening.

 

[William839]

I'm with @jonheld on this. It's an electrical gremlin.
Now whether its ignition side or fuel pump side, that's the question. Both will instal kill an engine if interupted.

@William839 ,
1) have you added anything to the battery posts or loosened the battery connectors recently for an accesory? (been there, that's why I'm asking).
2) will it instantly restart while on the incline or does the rig have to be level?, nvmnd, you ansered that in post 6. So why won't your brakes hold on a hill? That's terrifying.

Nope , nothing has been touched