Cold starts fine but then stalls, requires priming to restart

[DIESELMAX403]

Whenever it gets cold outside (around 35degF or lower), my truck starts up fine but then stalls after 3-4 seconds. This happens consistently. To restart, I push the fuel primer on top of the filter housing 4-5 times and then restart. I do not open the bleeder screw. Like clockwork, it starts, runs a little rough then smooths out as it warms up.

I live in southeast Texas and my truck is usually in the garage so cold starting is rare and this issue is only a minor inconvenience. However, I would like to solve the problem. Has anyone experienced this problem? I am thinking that it has something to do with fuel bleeding back past the low pressure fuel pump. The high pressure injector pump must be OK since it always starts initially.

One other piece of information is that this does not happen when I run the block heater. I don't understand how this would affect the fuel pump. The only thing I can think is that not as much fuel is required to start warm and it manages to deal with less fuel before normal low pressure is restored.



Any help would be appreciated.

Thanks,

DieselMax403

[DmaxMaverick]

You have air leaking into the system somewhere. If only 4-5 pumps (or anything less than 20-50) gets it started, it isn't much at all. Using the block heater may be just enough underhood heat to minimize it, or you have a seal that isn't "shrinking" as much as it would if it were colder. It is usually nothing more than a poorly seated fuel filter. Have you tried to reseat or replace it since this started? Do you find any evidence of fuel system leakage or seepage?

It could be the fuel filler cap, with a defunct vent (which will exploit any leak during a cooling cycle). Try leaving it loosened after a hot shutdown, before your next cold start. Or, just replace it, they're cheap enough.

[DIESELMAX403]

DmaxMaverick,

Thanks for the quick reply. I had the same thought about air leaking into the system but did not know where to look. I do not have any fuel seepage. I ruled out the fuel filter since I change it every 10,000 miles and this problem has been around through several changes. I was thinking maybe the bleeder screw o-ring was leaking when it gets cold. Heat from the block heater could affect this. I will try changing this o-ring in addition to the fuel cap. Hopefully this will solve my problem.


Thanks again,

DieselMax403

[Dmaxwrench]

It sounds as though you have air entering the fuel supply side. PM me if you need assistance with this problem.

Dale

[conway]

I had a similar problem and traced it to the three torx screws that hold the pump button down. It seeems to have loosened. I retightened and had no problems after that.