Grid Heaters On = FP Drops

[Joe Mc]

Noticed when the grid heaters are on, after an overnight or long sit, the fuel psi drops from 15 to 13 at idle. When they go off the psi goes back up. This cycle continues till the heaters go off. I assume this is as normal as the lights dimming when they go on. Just want to be sure - Thanks

 

[Lordsman]

Fuel pressure

I've noticed on mine the reduced voltage will drop the pressure.

Very noticable when cold. You have good pressure on your '99. How many miles so far and is it your original pump? Mine runs between 13-10(post filter) when warm, depending on load. No fueling mods(yet).

 

[Joe Mc]

Re: Fuel pressure

Thanks, I figured it was normal, but had to be sure just installed the gauges weekend before last. No fuel mods either . . . yet .



I have almost 94k, the lift pump was replaced a few thousand ago (early April). This is the first replacement pump for me - I purchased truck late last May. Couldn't say how many previously.