New to the forum with a lift pump problem. I have a 2001 CTD 24V with 155K on it. I replaced my stock lift pump with a Carter P4601HP. I also have a Quadzilla Commander with the Dodge fuel pressure kit. New 3/8" gas line installed with the lift pump on the rear frame rail. The pump puts out a lot of fuel but the pressure is reading only 8 psi at idle and 1-2 at WOT. The stock was reading 2psi at idle and 0 at WOT from the Commander's perspective. Replaced pressure transducer with a new one. Same fuel reading. Replaced Carter with new Carter and same pressures. Transducer is at VP44 inlet from banjo bolt. Fuel filter is fairly new and I have new line from the filter to VP44. Do I now get a mechanical fuel pressure gauge, new lift pump, or what? The Carters both were the P4601HP and not the P4600HP so I don't know why I am not seeing 15psi at idle. I've got mild modifications on the engine with only a 4" exhaust, K&N stock air filter, Superchips performance tuner, and the Quadzilla Commander.

 

not sure on the 3/8's line but with my 1/2" line i only see around 10psi with my 4601hp. w/o throttle i only loose about 1-2psi of pressure because of the volume i have stored in between the pumps(carter and vp). i was hoping for more pressure but as long as i have the volume im ok with that for now. you also might want to check into bypassing the stock lift pump as they can be a restriction if they fail.

 

Ck to be sure you have full charging system voltage at your pump(not pulse width modulated) and that you have no restriction on the inlet side.

Bob

 

Thanks, I have the OEM liftpump removed and bypassed. I'm running 10 ga. wire to the pump and have also checked it with a 10 amp battery charger. With the ignition on but engine off I see only 8 psi with either an engine bump or with the battery charger. Seems like with the engine off I should see more pressure....

 

Do you have the updated (0 - 40 psi) sender and the updated software? If not, call Q'zilla.

I also had issues with mine due to my not having the sender grounded properly.

 

I do have the updated software and the 0-40 psi sender and found out the hard way about the grounding of the transducer. I originally changed out all the plumbing with aluminum AN-6 fittings with a transducer take-off. Anodized aluminum sucks for grounding so I had to put the original banjo fitting and Quadzilla bolt back on. I'd like to find a good grounding strap that I can put around the sensor so I can mount it on the aluminum fitting for better flow, though. It seems that I should have the best ground with the setup I have (OEM banjo and Quadzilla adapter bolt).... Summit Racing has a nice 12.5mmx1.5 to AN-6 adapter for anyone wanting to change their plumbing (RUS-670510 is the part number).