BarryG

Ok this is starting to happen more frequently now so I need to get it figured out.

Truck starts like normal then dies. It takes cranking it 20-30 seconds to start the second time. Then all is well for the rest of the day.

Conditions:
Cold truck so far only after sitting overnight
outside temps 10-45 degrees
grids are working not that it is cold enough not to start without them
RASP fuel pump with stock backup
Truck starts normally very quick
dies after running 5 seconds or less
crank on it for 20-30 seconds and she starts again and runs/starts fine the rest of the day.
no unusual codes
Has done it with a fuel level from full tank down to 1/2 tank

I can only think of maybe a lot of water in the filter cannister which I have drained. It has done this over many tanks of fuel (10+) and I have even run the fuel low a few times to replace as much as possible in case it was water or other contaminated fuel. It may be loosing its prime but do not smell or see any fuel leaks, wet spots etc. However I have been working so much by the time I get home it is well past dark and honestly cant see that well even with a drop/flashlight to really see any wetspots or weeping fuel. There are no drips on the driveway either. Anyone got any ideas? How do you check for loss of prime? Anyone have any other ideas?

johns99

Check the suction line from the tank to the LP for any signs of deteriation. Any leak on this part of the fuel system can allow air into the line without showing any signs of fuel leakage. Most of the line is metal and may have chafed on the frame or brackets, but the most likely places are at the tank and just before the lift pump where they are flexible hoses. If you have compressed air, set it for around 5 psi and have an assistant pressurise the tank while you inspect the line. This will force fuel out of any leak and make it easier to spot. A shop towel around an air nozzle works well. Check the inlet fitting to the lift pump carefully too. Hope this helps.

Geico266

What is your fuel pressure?