When I installed my gauges last night My fuel pressures were spot on. Today, once after a 15 minute drive, it dropped to 5 psi for about 3 seconds then returned to 14. Now it seems like it is dropping out quite a bit more. Sometimes if I punch the throttle it will come right back up. It is hard piped with no isolator and is plumbed into the port closest to the fender on top of the filter house.
Is my LP dying or is something else happening?? Could I have maybe plumbed it into the wrong port on the filter? I just can't believe this!!

 

Mine was giving flakey readings last week.

One new lift pump later, and all's well.

 

Yup, your LP's days are numbered.....those fluctuations are a sign that it is taking a dive....replace it before it can cause some serious problems....

 

CTDNut and Shovelhead are correct!

My LP was doing the same thing. During the LP volume test you can hear the LP grining and humming off beat. When it was humming smooth the pressure would jump up to 14 PSI and when it started grining it would drop fast as low as 5 PSI...

Oh... If you under warranty yet... Do the Volume test... If you got a camera take pictures! This got me a new LP without say a word! Digital Camera's are nice tools!

 

Mine is doing about the same thing except not as severe. Only difference is that this one was just installed under warranty along with the vp44 from dodge. less than 2000 miles ago. I'm going to install a fresh one back at the tank and just leave this one in place so I can hook it back up if more warranty work is required.
Dodge claims it passes the flow test so it is ok!!!

 

ALright, I knew that was the issue, just needed a push!! Found one at Napa for 200.00 and one at the local Cummins shop for161.00. Will get the one from Cummins after I drop the Kid off at school.
Is there a procedure for replacing this somewhere??

Chris

 

Easiest way I found was to remove the fuel lines from the filter housing and remove the entire filter housing from the truck ... that opens up a nice work space! Next, unplug the wiring from the lift pump.

Remove the fuel line quick disconnect on the tank side of the LP and unbolt/remove the lift pump. Once the lift pump is on a bench, remove the fuel lines and replace them on the new lift pump (make sure to replace the banjo bolt washers, 2 per bolt). Replace lift pump and connect fuel lines (new washers!) and wiring harness. Replace filter housing and reconnect the fuel lines to the housing. This is a great time for a filter change too!

Bump the engine to allow the lift pump to cycle ... will run for approx. 20 seconds, this will fill the filter housing and purge the lines of air. You may have to bump the engine 2-3 times to sufficiently prime the fuel system. Start the engine ... you may have to crank it over a couple of times to get it started. It'll run rough for a few seconds, then smooth out ... now your back in business!

If you have trouble starting the engine, try cracking a couple of injector lines, bump the engine and watch for the presence of fuel at the cracked lines then tighten ... this should purge the air out. Start the engine! Hope this helps.

 

Barry,
I can see where Dodge would say it passes the flow test. Mine will have 15 psi and then drop all the way to 0 then back up to 15 again!!
I picked up the LP and 6 banjo washers today and will jump on this in a couple of minutes

Thanks again to everyone

Chris

 

New pump is in!!! Pressures are 16 idle, 14 cruise, 12 WOT. No fluctuations and all seems well. Install would have taken half the time if the studs would not have backed out of the pump housing

After looking at that pump all apart it really looks like the motor is the weak link. I was suprised to see all metal part in the pump and not a plastic impellar.

Chris