My Boys truck stalls when slowing down or stopping

[papahud]

1990 F350 2wd w/Hypermax turbo, e4od w/transpak , new poly saddle tank and more. Anyway, truck starts fine drives for a few miles and then stalls when we slow down to turn or to stop. After bleeding air in shraeder vale and cranking 4-5 times it starts and drives another few short miles and does it all again. Thankfully not at an intersection.

All tees,Os,returns,injectors are original except for crossover line that came with the Hypermax kit. Ran flow test 7-8 oz in 10 seconds after it had run awhile. Only 1 oz when tested cold cranked. No fuel pressure at shraeder valve according to my gauge at any rpm. Hows that possible and it starts? Changed fuel filter earlier this week. Seemed to be air bubbles in the diesel in bleeder tube on fuel pressure tester.

Have fuel seepage at front bottom of IP cover but been there since I got the truck 60k miles ago. Hope someone knows the answer to the problem.

 

[smoking89IDI]

Correct me if I am wrong guys but can the fuel selector leak air in also? That might be it.

 

[FordGuy100]

It kinda almost sounded like the lift pump is starting to go out on you if you have no pressure at the the valve.

Other then that, what you could try to do is next time when it shuts down, quickly take some luke warm water, about 12 ounces and poor it over the top of the IP. If its starts up no problems, it means the IP is toast and you'll need a rebuild or a new one.

 

[Ironman03R]

Change your lift pump. Similar to what mine did. Changed 2 fuel filters several bottles of fuel treatment and tow bill later I changed the lift pump.

 

[towcat]

Correct me if I am wrong guys but can the fuel selector leak air in also? That might be it.

the return system should have no pressure in it at all. One of the indicators of a bad FSV is pressurization and stalling.You will see consistent air bubbles in the return and the return line caps would leak. Another idication of a bad FSV is one tank draining too quickly and the inability to draw fuel off the other tank.
With the "new" diesel formulation, I've been seeing FSV failures more fequently than before.

 

[FordGuy100]

Correct me if I am wrong guys but can the fuel selector leak air in also? That might be it.

I dont think it could leak air in, but it could allow for no fuel flow from the tanks.

 

[Evil_Jester]

heres something else to think about. was it below half a tank of fuel? my truck had those little valves halfway up the pickup tube, i guess thats what was causing my problem, after i cut em off and made a new pickup line it stoped acting up. it was fine going down the highway, but as soon as engine rpm would drop it would stall. had to switch to the other tank to get it started again.

 

[papahud]

I thought lift pump til I checked my records and it's only got abot 19k mi on it.

Considered Lo Sul fuel since I'd forgotten DieselKleen so I put in extra dose and 1/2 qrt.ATF. Stalled twice since then. I to had a tow bill home.

Why no fuel pressure tho? I wouldn't think it would flow test so well.

The tank was low but I was on the new tank and the pickup was fine. I can switch tanks and it runs fine and the gauges read correctly.

 

[Diesel JD]

Well if it has no fuel pressure at any RPM it STRONGLY suggests the lift pump no matter how old it is. If its healthy it should make about a 1/2 quart to a quart of fuel in 15 seconds of cranking, more if the engine is running at all. On your gauge it should show 4-6 psi. <4 is not enough more than 8 may be too much. The truck can run somewhat because the injector pump has its own internal transfer pump. Its not good to run it much like this because that strains the injection pump, plus doesn't give it as much fuel as it needs. The fuel cools and lubes the injector pump.

 

[towcat]

Here's my suggested course of action.
first change the fuel filter.
If no change then change out the fuel pump
keep an eye on the FSV, that should be your last item if the above two don't cure things.

 

[f-two-fiddy]

1990 F350 2wd w/Hypermax turbo, e4od w/transpak ,
All tees,Os,returns,injectors are original except for crossover line that came with the Hypermax kit. Ran flow test 7-8 oz in 10 seconds after it had run awhile. Only 1 oz when tested cold cranked. No fuel pressure at shraeder valve according to my gauge at any rpm. Hows that possible and it starts? Changed fuel filter earlier this week. Seemed to be air bubbles in the diesel in bleeder tube on fuel pressure tester.

Have fuel seepage at front bottom of IP cover but been there since I got the truck 60k miles ago. Hope someone knows the answer to the problem.

That flow test seems like a very poor performing lift pump. The air sounds like the 17 YO return system is starting to fail.
The IP is capable of pulling fuel at higher RPM's.
How many miles on it? It might be time for a new IP/Inj's?

 

[papahud]

Probably time to change all the lines front to back. Go Holley red. Any other recomendations...Carter has a marine type for about the same price. Should have done it when I first heard about them (only $69 at Summit Racing then, been awhile).

New Tees,Os & Return lines. Fuel filter was the first change.

I didn't realize that the IP could pull enough fuel to run some but it sure makes sense/

 

[Agnem]

Fix what you know is broke first. No pressure at the filter head is your top priority thing to correct. Everything else is just speculation at this point.

 

[papahud]

I'm with you on that. With 4 teens eating everyday I don't have the $$$ to start sticking on parts.
Problem is I don't know what's broke.

 

[papahud]

Think it's the fuel tank PU. Filled to 1/2 tank and ran the stalling routes. No probs.

Does anyone have an idea why I don't have fuel pressure? Maybe the Ford adapter is screwed up. Works on the Sub.