Quote:
Originally Posted by rustynuts
There is a fuel anti drain back valve on the pump. It may be letting fuel pressure back into the tank if it is leaking a bit.
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thats my bet.
if like TJ Wranglers the check valve to stop fuel running back into the tank from the injectors is a semi integral part of the pump
if the valve has some leakage, fuel in the lines etc will run back to tank and you have to do a long crank or several to prime the fuel line and build up pressure before the injectors can squirt fuel into the cylinders for it to fire
with hotter temps, components within the check valve expand and form a seal, but when cold things shrink and allow leakage. we are only talking microns here, but thats all it takes for a leak
best way round it is to switch on the ignition and wait 10 seconds or so, this will allow the pump to run and build up pressure, then fully turn the switch to start
if this procedure cures your cold start then that proves the valve in the pump is a bit wonky. can stay like that for years without causing a problem