Does anyone know what the liftpump fuel pressure on an 06 should be at the CP3. I have had some pinging noise and some nailing noise, I unhooked my xzt and the noises improved but not completely. Today I tied my shop fuel pressure gauge between my GPD 2 micron ff and the CP3. KOEO the fuel pressure would go to 6psi then immediately fall to 4psi and hold. With KOER, fuel pressure was at 9psi at idle then on road test would drop to 2 psi at WOT, just driving normal fuel pressure would stay 8-9 psi. Hook the XZT back up and road test, same fuel pressure for normal driving, however at WOT the fuel pressure would drop off RAPIDLY to 0 psi. Also, does the Dodge fuel delivery system have check valves? At shut down it does not hold any fuel pressure, turn the key off and the gauge immediately drops to 0 psi.

Thanks,

Tim

 

That's about normal for a 2micron filter - try the same test using a combination pressure\vacuum guage - if pressure falls to 0, the lift pump is doing it's job - if vacuum falls toward 10"HG, the CP3 internal lift pump is in draw mode, pulling fuel from the tank - that can depend on the age of the filter.

Other than that, it may be time for an external lift pump upgrade.

 

Thanks for the reply, I'm was leaning toward putting an external pump on it any way, question is, go with a Fass or similar, or just an assist pump?

Thanks,

Tim

 

I went Fass because GDP didn't exist at the time (hint). It is not so much pressure as volume to the cp3 that is important. But, how can you measure volume running? The first gear/pumpchamber in the cp3 takes care of pressure (80-180 psi) to the other three but requires volume. I do know that my Fass will supply incredible volume as I tried it. Filled a gallon jug super quick when I disconnected the cp3 supply hose. Try the same thing with the intank pump, see what volume you get. Can't recall what the required volume is for the cp3, lost that file long ago....Anyone know?

 

My self engineered GDP Walbro pump and regulator runs 19 psi through my 2 mic filter @ 19 psi. I've tried others........trust me GDP is the way to go! Buy the kit! I went about it trying to save some money, so thats how the system became self engineered. It would have been much easier on me, to spend the extra bucks and just bought it either straight from Rich @ GDP or thru Lary @ DTR store. That, and I wouldn't have to been under my truck 3 times for 3 different pumps before figuring out that Rich had his system all figured out WAY better than the others!

 

Thank you gentlemen, I was looking at the raptor pump from Air Dog, it has internal regulation so no return line needed? Also planned on calling GDP, Richard was excellent when I purchased the 2 micron set up over a year ago.

Thanks for the great info,

Tim

 

Just an update, i ordered an Air dog 100, will advise after install with pictures.

Thanks boys,

Tim