I just had a FASS 150 fuel pmup installed. I was reading about 18psi on my fuel pressure gauge and now its really bouncing all over the place. mostly from 12-15 psi and occasionally it will fall to about 6 psi and then the engine starts to cough and miss. Even stalled on me rolling into a stop sign. Engine no cranks about 6-8 seconds before starting when it used to fire in less than a second. Any ideas on why it is doing this??? need some help

 

Possibly a bad electrical connection.

 

Sounds like you have LP pressure while cranking so failure of FASS is not probable. Rotten fuel, water, or filters possible?? Are you where it's really cold and gelling a posibility?
Could you have a vacaum leak? That will make pressure jump around, And you just opened the lines for upgrade.

 

What kind of a guage do you have? Could be a bad isolator.......seems to be common!

 

Have ISSPRO Mechanical gauges. I dont think it can be the gauges as it was running solid before FASS Upgrade. Now tonight when i turn key on i can here fass pump running and guage reads 15 but truck won't start. Just keeps cranking. Anyone have any suggestions? I'm at 1/2 tank of fuel and truck ran good first half tank.

 

Did you do the draw straw too? Sounds like it is sucking air somewhere......