I have searched the prior posts and articles and have not found anything that reflects the situation I have - if one exists, please send me the link!
When I start the truck in the morning, the engine stumbles a bit and acts like it's going to die. It then idles and runs "smoothly". This problem happens only if the truck has sat for at least 10 hours, and not every time.
On Monday it DID die, and didn't want to restart at all! I don't believe I drove the truck at all on Sunday, so it sat a LONG time before the restart. I smelled no unburnt fuel in the exhaust after a combined cranking time of 15 seconds, I had my normal 12 PSI of lift pump pressure before cranking (measured at the VP44 inlet). I disconnected the VP44 wiring to look for issues and found nothing. Reinstalled and the truck fired up after a couple seconds of cranking it lit off. Clearly that could just be a coincidence, and if I'd just kept cranking a few more seconds instead of disconnecting the electrical it would start. No sign of a FUEL leak anywhere, even back of the block. No idea if it's sucking air somewhere, or if that is even a potential problem at startup.
My injectors are stock rebuilds, maybe 15k miles on them. My EGTs at highway speed seem higher than before the stumble started, but it's also gotten a lot hotter and I dropped my tire pressures around the same time. I do not have a chip of any kind. Fuel mileage is about the same as always, hard to judge as I've towed more recently. 16' utility trailer with some deck lumber, nothing heavy like a skid steer, etc. My OBDLink shows the same type of data as usual, little higher IAT as it's summer. I buy my fuel at the same places as usual.
It sounds like your loosing prime of the fuel system. Just early signs of it any way. It could easily be the return, back of the head or tee it connects to. It is possibly for it to leak air into the
I have searched the prior posts and articles and have not found anything that reflects the situation I have - if one exists, please send me the link!
When I start the truck in the morning, the engine stumbles a bit and acts like it's going to die. It then idles and runs "smoothly". This problem happens only if the truck has sat for at least 10 hours, and not every time.
On Monday it DID die, and didn't want to restart at all! I don't believe I drove the truck at all on Sunday, so it sat a LONG time before the restart. I smelled no unburnt fuel in the exhaust after a combined cranking time of 15 seconds, I had my normal 12 PSI of lift pump pressure before cranking (measured at the VP44 inlet). I disconnected the VP44 wiring to look for issues and found nothing. Reinstalled and the truck fired up after a couple seconds of cranking it lit off. Clearly that could just be a coincidence, and if I'd just kept cranking a few more seconds instead of disconnecting the electrical it would start. No sign of a FUEL leak anywhere, even back of the block. No idea if it's sucking air somewhere, or if that is even a potential problem at startup.
My injectors are stock rebuilds, maybe 15k miles on them. My EGTs at highway speed seem higher than before the stumble started, but it's also gotten a lot hotter and I dropped my tire pressures around the same time. I do not have a chip of any kind. Fuel mileage is about the same as always, hard to judge as I've towed more recently. 16' utility trailer with some deck lumber, nothing heavy like a skid steer, etc. My OBDLink shows the same type of data as usual, little higher IAT as it's summer. I buy my fuel at the same places as usual.
Any trouble-shooting advice is appreciated!