I installed a fuel pressure gauge tonight.
It is manual gauge and I just tapped into the 1/8 NPT port on the front of the pass side head and zip tied it outside the windshield for now.
Anyway, made some interesting discoveries.
Fuel pressure at idle is 75psi.
System is bone stock other than check valve removed from the front ds head when I installed the rubber line to clear the Terminator pumps.
from a dead stop fuel pressure drops to 28psi!
If I roll into the throttle it doesn't drop much at all, but a dead stop with foot to the floor, it will drop about 15psi in 1st and 2nd and spike back up after shifts. It spikes back up after the 2-3 shift, then as 3rd winds out it drops like a rock!
It also takes a while for fuel pressure to come up when you turn the key on, like 15 seconds and the gauge slowly moves up to max psi
My friends OBS
on which we just installed an electric fuel system with a stock SD
pump supplying snaps the gauge instantly to set pressure as soon as you turn on the key.
I have been having a cold start issue, the truck will fire off then die immediately, or won't fire off at all. It takes a while cranking 30-40 seconds minimum, then the truck will crank faster, faster, faster, faster, and finally start.
Today when looking for a place to install the fp gauge, my friend removed on of the BOSS O ring fittings from the fuel bowl and some fuel drained out.
We put that back in and installed the fp gauge in the head.
Well it took FOREVER for the pump to build up fuel pressure and the truck would not start! When the pressure came up, truck started exactly like it has been starting in the morning after sitting all night. faster, faster, faster, faster, finally lights the engine off and engine turns really slowly for a few seconds then comes up to normal idle RPM.
So, in your professional opinions, do I have a weak fuel pump? Or is it just not able to meet the demand of my comparitively small injectors?
If so, what is the cold start issue.
If I do need to replace the fuel pump because it's faulty, what should I use? Stock? Bosch 044 ?
Thanks for any input.