White00

I finished my install of the fass and everything is working great. I am seeing 18psi of pressure at idle and can pull it down maybe 1 pound at WOT. It makes my fp gauge look stuck. My question is, I've read that the VP doen't like too much pressure over 16psi. I read on the site about adjusting the fp by changing springs or streching/compressing. Where is this spring located, and to lower pressure do I lengthen or compress???? Thanks for all the info!

ADAM

Mike Holmen

I have my Fass at 18psi as well. Its not a problem for the VP44 pump to handle 18psi, as people have been running over 20psi with the additional pusher pump for years now. The injection pump has its own pressure regulator that set around the 16 psi. So I don't know if you can see the pressure swings of 18psi to 15psi, when the injection pump dumps the extra pressure. My gauge you can see the pressure swings from 18-15-18 psi. The pressure swings will ruin the gauge in short order so I just installed a cheap $8 needle valve. Now the pressure is pretty steady and I have to install my 0-30psi when time permits. If you have to the pressure spring is under the bypass AN fitting. Just remove the AN fitting and the spring should come out. But this is total unnecessary.

graphitecumnz

The injection pump will bypass pressure over a certain amount via the return line... I though it was something like 14 psi. I also believe that once you are running too much fp you will experience a hard start condition...

Mike Holmen

The lift pump just gives a quick shot of fuel then shuts off during a start sequence. Then it waits for the engine to start, then it pumps. Your right though, if you pump-up the pressure to 18psi proir to starting. The truck will start like a new truck, requiring 3-4 cranks to start.

GIT-R-DONE

I had the wrong spring in mine, installed a mechanical gauge and was running 26.5 lb. of pressure for like 3 weeks. I had no hard start trouble. SInce then, I reinstalled the softer spring and now see 12 lb. all the time.

renegade681

I might have to get the other spring. I do have the hard start problem right now. But its only hard to start after the truck is warmed up then shut down. If it sits all night no problem starting up. What are you guys running for fuel presure gauges? I have the Ultra lites and its pegged right now.

graphitecumnz

I run about 14.5 to 15 psi...