I recently installed a Scotty Systems fuel line kit (www.scottysystems.ca) on my truck. I also have a low fuel presure light I got from BD Power. Light set to come on when fuel pressure drops below 5 psi. When I first got the light installed, it was on all the time. Checked fuel pressure - it was 2-4 psi (should be around 8-10 psi). Time for a new lift pump. My truck was and is still under warranty, so Dodge put a new LP on. They installed the upgraded kit where the new LP goes in the tank. The old one was on the side of the engine, and the theory goes that the engine heat and vibration shorten the LPs life. So, new one is relocated, and installed in the tank where it is kept cooler, and no longer gets vibrated by the "paint shaker" Cummins. My low fuel pressure warning light would only come on now when I got into the throttle and climbed above 2000 RPM, and would go out as soon as I let off. It would also "flicker" when towing on steep grades where more power was needed. I started doing some research into a cure. Boy did I learn something!! 1) I learned that when Dodge installs the LP relocation kit, they substitute a "dummy" aluminium block where the old LP used to live on the side of the engine block. Seems like an OK solution, until you learn more, it leaves two unnecessary banjo bolts in the system - read on. Here's a pics of the block I am talking about. 2) I learned that these "banjo bolts" they use to plumb the fuel system are amazingly (to me anyway) restrictive. Here is a picture of the magnifying glass shaped portion of the banjo bolt, with the tiny hole that all the fuel must flow through to feed the engine visible. It is next to the line used in the scotty kit. Can you imagine, towing all that weight - 15,500# for me (~7000# truck + ~8500# TT) and every drop of fuel used has to flow through that little hole that looks to be what, 3/16"? 3) Next picture is of the fittings/plumbing used in the scotty kit. Looks like a garden hose in comparison. 4) Here's a picture of the banjo bolt assembled, and one of the banjo bolt itself next to the scotty fitting. There are a total of at least 5 of these banjo bolt connections on a stock Cummins. One on the inlet side of the LP, one on the exit side of the LP, one on the inlet side of the fuel filter, one on the exit, and one on the inlet side of the injection pump. With this new system installed, my low fuel pressure light comes on only when I hit the key to the ON position. As soon as the engine fires, light goes out. It also doesn't come on when I get in the throttle, or when I am towing. This is with the same LP I had before. If you have a 1998.5 to 2002 24V Cummins, somthing like this may be something you want to look into. Just so this doesn't sound like an endorsement of scotty, a company called Vulcan makes a similar kit. I mention scotty's as that is the one I went with.
The Scotty Kit is $169.00 USD plus shipping IIRC. New LP (and in-tank conversion) was warranty by dealer.
Oh sweet lord,get a set of guages,I cant believe that anybody who owns a 24v would drive it without a fuel pressure guage.Secondly,the intank pump is a horrific idea as well,when it goes,it should be fun dropping the tank huh?SO-relocate the lp to the frame using the vulcan or scotty kit,they are similar.I went with the vulcan,it nixes all the banjos and uses new 1/2 inch lines and even has a outlet for a guage,and it easily has everything you need to relocate the STOCK pump to the frame next to the tank.You will enjoy 14psi at idle and 10 or more wot.I get 11 WOT with a edge comp drag with the wire tapped.The kit is like 140 bucks plus the cost of a pump which you would need anyway.I cant believe that there are still warrantied trucks out there!
I have gauges. No need for a FP gauge, I have the light. It will tell me if/when there is a problem. I don't care if the FP is 8, 9, or 15 psi, just that it is above the 5 psi threshold. The intank pump my be a "horrific idea" but it wasn't so "horrific" to me since it was 100% free. If it goes, I will undo a few bolts and drop the tank, no big deal. There are hundreds of millions of vehicles on the road with in tank fuel pumps, not a bad system in my view. Having the LP on the frame may be a good spot to make it easy to replace, but it is also exposed to salt, snow, ice, and slush in the winter, and rocks, sticks and anything else you run over when off roading. If a big rock knocks it off the frame, you're done. Where I live (where it actually gets cold in winter) having 3" of ice built up around the fuel pump wouldn't be ideal either. I guess there are pros and cons to each set up. I like mine the way it is, and don't plan on changing anytime soon.
Ran into the same problem with mine. Although mine had the in tank pump in it when I bought the truck. I put on the vulcan kit and an external LP and it works great. The VP is still weak at times(cold) but all in due time.
I didn't know that the in tank pump was so weak when I bought the truck. The pump was changed last month, and I just put the Commander on for my guages. The highest fuel pressure I have seen yet is 7, yes 7 psi. It drops down to about 2 at WOT. This is after the install of a Vulcan big line kit too. I don't think I am gonna modify the fuel system any more, I just hope the VP44 craps out within the next two years because I got a 2 year warranty with the truck. Oh well, I'll just drive it the same either way.
Glacier Diesel Products, that's how I feed the 24V, use to have stock lift pump on the engine, truck has 170K on it, yes STOCK lift pump. Started leaking last week, don't know why don't care. Replaced the system with GDP new on rail pump with big line kit and totally replaced the stock system. Stock lift pump before I replaced it was 14 to 15 PSI at idle, and 8 to 9 PSI AT WOT. That was stock lift pump with no mods. Now with GDP kit, 18 to 20 psi idle, and 14 PSI WOT. Can pull it down below 14. It's worth it and it only runs at 5% of it's duty life. If you are getting pressures below 10 PSI you got fuel pressue issues. Besides Richard the owner of GDP is a great person to deal with. I looked at all the other options and in my opinon this was it. Rob
I just ordered a Holley blue fuel pump from Checkers for about 110 bucks. I am going to put this pump inline with the intank pump as a pusher pump. It is a 110 gph pump and can max at 14 psi, so I should see much higher psi's than with my peewee in tank pump. I'll let you guys know how it goes. opcorn:
Pump is on, with regulator and set to 14 or so psi at idle, cant pull the thing under 12 with the smarty on #7, so I think I can rest at night knowing I have good fuel pressure. waytogo
I use a FASS 200gph race pump operating at 45psi and I replaced the supplied 3/8" hose and fittings with 1/2" hose and fittings. If that ain't enough its time to pack it up and head home . . . . .
There has been much talk on this subject in not only this forum but many others as well and here is what I think is a positive contribution to the topic. We recently endeavored to re-engineer what can be legitimately called a marginal lift pump fuel supply setup for anything over stock power levels, and is sometimes dicey at even stock levels. Whether we are discussing the block-based lift pump or the in-tank lift pump retrofit the OEM setup leaves much to be desired both in terms of performance and reliability. Without getting into a discussion of dynamic vs. static pressures and so forth, we can all agree that flow is the critical parameter for the VP44 injection pump inlet. Without knowing discharge pressure of the lift pump or a flow-metering device, little can be said about actual flow rate to the injection pump so we all rely on the inlet pressure at the pump. Given fluid mechanics, this is a safe way to gauge what you are feeding your injection pump. Thus, actual inlet pressure is technically irrelavant but in our cases it is the only gauge we have to go off of. In the case of the VP44 it is very fickle as far as what pressure it wants to see at the inlet. Based on Bosch literature and Cummins owner personal accounts, the NPSH required by the primary stage vane-type pump in the VP44 seems to be at least 5psi to avoid cavitation concerns. Also, anything above 12-14 psi is reputed to be too much pressure multiplication and causes excessive exercising of the VP44's internal bypass circuit creating heat and eventually damage. To this end we decided that a constant supply of 8-10 psi should be sufficient. To achieve this, we use basically a return circuit from a pressure regulator placed just upstream of the VP44, after an aftermarket lift pump. Therefore, concerns about deadheading and burning out an aftermarket high-performance lift pump go out the window because at low-flow conditions the fuel is recirculated back to the tank, at a low drive pressure and hence a low duty cycle. When fuel demand increases, the regulator seats and allows the fuel to go directly to the VP44. This is not new technology nor is it the first time somebody has run it on a Cummins. It is however flexible in design to allow for a target HP in any given case, all lines, fittings and pumps/filter setups have been tuned and sized accordingly for individual needs. The difference in the system we've been developing and others that are readily available is that it is an application specific, highly engineered solution for fueling a VP44 whether its 350HP or 1100HP. There are several pump options to avoid the growing trend of overfueling a mild power application or underfueling a high power application. In addition, this system has been designed on paper, tested in the field, and been through several iterations to best suit the conditions a pickup truck endures. Its not as inexpensive as a pump-relocation kit or bolt-on lift pump, it is a COMPLETE replacement of the stock setup, down to the miniscule banjo bolt on the VP44 pump inlet. Just thought we'd share some of the fruits of our labor. Thoughts?
FASS going on soon. I had a local VP44 rebuilder tell me not to let the fuel pressure get below 8 psi ever & he told me to get the FASS on my truck soon. I can pull the fuel pressure down to 4 PSI with the Juice/Attitude.
That piece of **** holley blue is going to become shotgun target practice soon, I have a FASS right here that is going on on Monday. The Holley pump would start leaking every so often, pressure was like a rollercoaster, and I was sick of it. PULL!!!! BOOM!!! imp: I'll put up pics of the FASS soon.
FASS is on now, & I wished I would have done it years ago. With the Juice on 5x5, I can't get the FASS below 12 psi, & it recovers back to 16-17 psi almost immediately.
I am feeding mine with a Walbro GFS system w/2 micron FF from Glacier Diesel Performance. It has worked great sofar for me. My pressures are 16psi idle & 13psi WOT. I have one more shim to put in to bump the pressure up to 18-19PSI if I want to also. Harley Harley
