Engine/Transmission (1998.5 - 2002) Low fuel pressure at WOT with Fass DDRP

[DEWright]

I have an 02 3500 with a new injector pump, fass ddrp, relocation kit with 3/8" lines from the tank to the injector pump. Have big line kit 3/8' from the filter to the injector pump. Electric pressure gauge which has been checked with mechanical and is on the money. At idle, I am running 16-17psi, running down the road 12-13psi, at WOT it draws it down to 6psi. Did not use banjo bolts so the screen is not in the line. Engine is stock 191K miles. Do you think that I am having a problem with fuel delivery from the tank? Clogged screen or fuel tank, or both? I have tried everything except dropping the tank and cleaning it out. That is my next project, but what else is there if this is not the problem? I had two other fuel pumps on the truck, both were airtex and I had the exact same problem.

 

[JGamble]

is it a new FASS pump on it? I just blew mine a couple days ago and the same thing was happening till the engine started misfiring. Now I dont even know what will happen... . check out the thread if interested... . in "truck 911"

 

[BDaugherty]

Since I installed my jammer 2s, I've been able to drop my fuel psi at WOT down to about 12. I have 3/8" line from the factory pickup all the way to the IP. I've been thinking about getting the new draw straw that installs in the factory pickup unit and has 2 return lines. I'm thinking that either the "sock" is getting stopped up or the factory pickup just isn't big enough. One last thing, have you checked the screen that installs just before the DDRP? If you have installed it without a screen, I've seen trash cause your same symptoms. A buddy of mine had a big line kit with draw straw and walbro pump installed on his truck. The shop installed the inline screen after the pump instead of before. He started to have very irregular fuel pressure. We took the pump apart and found trash... possibly left over from the draw straw install. We cleaned the screen and moved it to between the tank and pump. He hasn't had a problem since.