Engine/Transmission (1998.5 - 2002) new lift pump

[lonewolf1]

lost fuel pressure... . and bought new lift pump amd mounted it on frame rail close to tank,. . but now only has 13 psi at idle. then step on gas and it goes to 0 or 1 pounds and no power. talked to dealer and they say they no longer worry about pressure that they check by volume. . said to get 36oz of diesel im bottle put rubber hose on the in side of pump and cycle pump with key 1 time and if its good it will empty the 36 oz... and it did do that. . but still no pressure on gauge... any help with this would be greatly appreatiated..... and also all new fuel hose has been in stalled with 3/8 hose fittings :--)

 

[Supermod56]

The stock L/P doesn't have enough steam to work that far back, some guys put a extra pump back by the tank to help the L/P. 0 psi is not good!! Did you try it in the stock location??? The Dealer volume test is a joke. If you want to run the pump back there, get a FASS or a FASSII.



Tom



2001. 5 2500 4X4 5-Spd LB QC Black. Catcher ECM, DD Stage-1's, AFE, Bully Dog 4" pipe, ATS Exhaust Manifold, Silencer Ring MIA, JAKE Brake w/shifter switch, Geno's Banjo's, 3 Autometer's on the A-Pillar, Gear Vendor's O/D, Firestone Air Bags, Redline Oil throughout.

 

[01smokinram]

Did you just relocate it to the frame rail or did you add a pusher pump? You may need to go with a pump that flows a little more that the stock one or put a pusher pump on with the stock.

 

[rweis]

I've had the OEM lp back by the tank for 50k. I bypass mine down to 12psi. OEM will push back there just fine.



If new, then I would take it apart (top) and check its vanes and check valve. Also could have shaft coupling fouled up. I assume it does run?



If new I would take it back.



I still subscribe to the 10 psi theory of the orgional testing proceedures.



Bob Weis

 

[OPoole]

A stock LP should work just fine it's a carter 15lbs. Do you have a good 12volts to the pump i would install a relay. Did you replace the banjos?

 

[Supermod56]

So the stock pump will work from that far back? Hmmmm, interesting, guess you learn something every day!! Too bad the Genius's at DC didn't put it back there in the first place!! Still getting a RASP!!!



Tom

 

[lonewolf1]

yes it does have good 12 v power and i did replace the bangos with 3/8 fuel hose and an nipples... . and i did not put a second pump thanks ED

 

[rweis]

I believe actually the lp works better back by the tank. The general consensus is that it pushes ok, but doesn't suck well.



When I put mine on the frame by the tank the lp is actually below the tank fuel level until the tank is in the last 2" or so and I generally do not let the tank get below 1/4 tank remaining. I think this helps keep the lp with a little feed pressure and the distance is about 24" rather than about 24" vertically and about 60" distance from the tank.



That is my take FWIW.



I put a bypass regulator on mine to keep the check valve closed (which seems to be a fairly significant failure point). 50k so far and expecting about 100k+?, but always carry a spare lp.



Bib Weis

 

[GBrock]

I had a similar problem the other day. Relentless Diesel determined that the LP was just fine. It turns out the drop in pressure was due to a really, really, really dirty fuel filter. Have you replaced your fuel filter lately? After Chris at Relentless changed the filter, I'm back up to 14-15 psi at idle and 7-8 psi at WOT. Before the filter replacement, my guage was reading 7-10 psi at idle and ZERO at WOT.