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markrinker
07-31-2004, 07:34
I am working my way through DP article(s) on possible stalling causes OTHER than the obvious impending FSD failure. Have narrowed down the scenarios in which #2 will stall, combined with hard (slow, much cranking) restarting.

...Its right after re-fueling - with the motor shut off!

I know this sounds insane, but I can predictably recreate the stalling problems by shutting down the truck during refueling stops. Yesterday I drove ~850 miles with only one stalling occurance, and there is a pattern at work here. Same thing the day before, sitting cranking at the fuel pump. Both days had hundreds of trouble free miles at 70MPH once restarted.

Since I drive lots of miles - I do let the tank get very low, sometimes within 1 or 2 gallons of empty. Maybe its classic FSD heat soak on a low tank of fuel (hot) so it may point more to the FSD than ever. But why the re-fueling connection? Could be that is the only time the truck gets shut off under 1/4 tank...

I am also wondering about the effects of the foam produced at refueling, and where they could be ending up in the fuel system. Possibly air bubbles in the pump or lines??? Would this cause a stall and hard restart?

Anyone else have this strange occurance?

Barry Nave
07-31-2004, 08:08
Have you tried removing the fuel cap before sutting down. Just an ideal :confused:

markrinker
07-31-2004, 09:50
Nope. What would that test?

HowieE
07-31-2004, 11:51
If you thing it is Heat Soaking while the engine is shut down don't shut it down when refueling. Your not going to blow up the world like the Do Gooder say you are.

markrinker
07-31-2004, 14:15
I follow you now. Yes, I have refueled many times while running - in fact, most of the time.

It doesn't stall out in that scenario.

I am pretty sure its the FSD. Its been a good excercise to eliminate all other possibilities first, but everything points to it.

tom.mcinerney
07-31-2004, 19:52
First thought came to mind--the fill process stirs up debris on base tank; causes partial clog of pickup filter/sock. I'm on BNave's track of hard prime....

(In speculative realm), if foam developed while running at low fuel level, fuel column would probably continue to pump. But if shutdown, the foam bubbles aggregate, air/vapor pockets not as easy to pump, aggregated bubbles suffer more compression, FIP loses feed. ????

FarmerDale
08-02-2004, 04:54
Mark,

You wrote
Have narrowed down the scenarios in which #2 will stall, combined with hard (slow, much cranking) restarting I would focus in on the slow crank speed. A warm engine will not have as much resistance as an engine that has not been run in 4-24 hours. Is there an increase in resistance in the cables running to the starter while things are warm, thus reducing overall voltage in the truck, esp the FSD?