Engine/Transmission (1998.5 - 2002) The VP44/LP Saga is like a bad soap opera

[MMoyle]

OK... So I am trying to figure out the best scenario to fix my poor fuel pressure problem. I recently (under warranty) had my VP44 and Lift pump replaced at 62K miles. They replaced the original lift pump with the in-tank setup. I installed half of the Vulcan big line kit (replaced the banjos on the VP44 and the Fuel Filter housing and installed a big line between the two) and put in a westach fuel pressure guage shortly after the dealer did the installation.



With the intank setup on a stock truck, I am getting 8psi at idle and can pull it down to almost 0psi at WOT. So after reading, reading, and more reading there is a pretty good consenscous that anything lower than 5psi at WOT could put the VP44 at risk of failure. Way to go Dodge!! Good job with that in-tank setup - NOT!



With a new VP44 installed, I would like to prolong its life as long as possible. So you hear things like FASS, RASP, Relocation kits, bigger lines, cam replacements with mechanical pumps, and so on. Which one to chose? mmmm... That is the question! As with all of us, we want a solution that works... ... ..... period. Yes money is an issue at times, but for me I just want the thing to work like the 12 Valves did. I feel the fuel system in our trucks is like 1 year old baby that never grows up. It needs constant attention, monitoring, and feedings (pressure) to survive. I am tempted to sell the truck and buy a 12valve again, but "I think" I am determined to get this right.



So here are my questions for you all:



1. I am thinking of running the in-tank setup along with adding the carter pump back to the original location. Do any of you have this setup? If so, has it been a reliable one for you so far? What kind of pressure are you getting with both pumps running?



1a. This question is a subset of question 1. I cannot find a "definitive" answer on whether to much fuel pressure will hurt the VP44. I found some that say it is fine, and others says it will hurt the internal seals. I could not find an answer on the web from bosch, but does anyone have any supporting documentation or experience that to much pressure will damage the VP44? I am thinking that both pumps working together may put out 25psi or more at idle.



I am fairly certain that the scenario above (running 2 pumps) will ultimately fail again. But how long is the question? If it will last close to 100k, I would be happy with that scenario. But I am not to sure.



2. Based on my reseach and opinions, I believe that going back to a mechanical fuel pump is the best option. That leaves 2 options - RASP and Cam Replacement. The RASP seems to be a good option and an option I may consider. I like that fact that I can set the pressure to what ever I prefer. The cam replacement option is a little extreme for me. I do like the option alot, but I can't rationalize replacing a perfectly good cam to fix a poorly designed fuel system. For those of you using the RASP setup, how many miles have you gotten out of it? Has it be fairly trouble free?



What would I do without TDR? Be lonely I guess.

Thanks Guys!

 

[nps]

I'd vote for the original LP in the stock location, or alternately relocate it to the frame rail. There are members successfulling running this configuration, but hasn't had that many miles put to it because of the newness of the intank pump. However other members have been running a frame mounted pusher and the stock pump successfully for many miles, so the stock LP is reliable when fed by a pusher. I believe this will get you to 100K. I've got 55K on my stock original LP that is being fed by a pusher.



I'd be concerned with a RASP having to suck through the intank pump. Think that may be a new configuration.

 

[MMoyle]

Thanks NPS. I think I am going to add the LP back to the original location and see what happens. It is also a cheaper option If I don't like to results, I will then shell out the cash for a mechanical setup in the future.



I have the same concern as you with the RASP having to suck through the in-tank pump. If I go that route, I may disconnect the in-tank pump all together and put the original pickup back in. THis way I would have the RASP with my stock pump (the carter in the original location). It really blows that we have to go through all of this crap because of a crapy fuel design. But - "it is what is it. "

 

[GWedekind]

I run the intank pump with a Holley blue mounted on the frame. Pressure is between 15-20. got about 50,000 so far on this set up and happy with it.

 

[chazj]

I'm facing the same questions except that I am now out of warrenty. I thought about simply adding a BD pusher pump to work in conjunction with the in-tank pump. However the pressure to the VP44 will exceed 20lbs. Even if I make the assumption that the latter won't be damaged; I contacted Autometer to see the effect on my 15lb guage. There advice is to replace it as the latter wouldn't last. The cost is another $200.



Now looking at Fass II. Have read that they can operate at the 15lb. range so, even though they are more expensive, I would spare the extra cost of replacing the Autometer fuel guage. I would have to remove Dodge's in-tank fuel pump though.



Decisions... . decisions.....

 

[rweis]

I put a RASP on my '02.



The RASP returns fuel to the tank filler (vent line in my case). I return the VP return line to the tank filler (vent line in my case) which frees up one tank return line that I am going to make into a fuel feed line.



Why? 1 fuel feed for the RASP, 1 fuel feed for the backup LP (switched on by the Hobbs switch). Both systems will be strickly for that system and will join right before the ff (inline in my case, OEM ff is on the shelf until I can get the heat out of it when it is installed in place correctly). The only common point will be the lp bypass check valve to keep the RASP from pushing fuel through the lp and a RASP check valve to keep the lp from pushing fuel through the RASP.



Yeah, the fuel system is a royal PITA! but like you said "it is what it is" (edited), and either you live with it or fix it.



As I understand it the VP is looking for 13. 5 # input and not more than about + 3. 5 # and not less than -3. 5 # (10# - 18#) because of a + - 2. 5mm deflection in a diaphram internal to the VP before the diaphram seals start ot be dammaged. BUT I DO NOT KNOW WHICH DIAPHRAM OR WHERE IT IS EXACTELY (help from someone who disects VP44's would help me (at least) quite a bit here).



Bob Weis

 

[nps]

I'm facing the same questions except that I am now out of warrenty. I thought about simply adding a BD pusher pump to work in conjunction with the in-tank pump. However the pressure to the VP44 will exceed 20lbs. Even if I make the assumption that the latter won't be damaged; I contacted Autometer to see the effect on my 15lb guage. There advice is to replace it as the latter wouldn't last. The cost is another $200.



Now looking at Fass II. Have read that they can operate at the 15lb. range so, even though they are more expensive, I would spare the extra cost of replacing the Autometer fuel guage. I would have to remove Dodge's in-tank fuel pump though.



Decisions... . decisions.....

If you want to keep the pressure down, use the Carter 4600. Puts out 8psi. I use it as my pusher. Got it off Summit for about $90.

 

[Short Stack]

Do what you must, but the VP44 will die sooner or later with or without other fuel supply. I am on my 4th VP44, only 90,000 miles. I think they will die anyway, anytime.

 

[BradyWilliams]

We sell Fass fuel systems and pumps. The reason that we like this option is that it fixes more than just fuel pressure to the VP44. You also get a very good filter system and also the ability to remove air from the fuel going to the VP44. The failures we see beside low fuel pressure is also water and dirt contamination and air that causes cavitation in the injection pump also. A 4 year warranty does not hurt either! We are a distributor for Fass if you are interested. Thanks, Brady

 

[ThrottleJockey]

Also with the FASS, it has an internal bypass valve in the event of pump failure, so the VP will still get it's fuel.



Use a big line kit, or build your own, with the FASS.

 

[MMoyle]

Thanks guys for the reply's! Ok FASS owners, how many trouble free miles on your fuel system?

 

[Fishin Guide]

See my sig for my fix.



Dave

 

[isb360]

Anybody running a fuel pressure regulator? Or am I missing something? Not rated for diesel fuel?



Example: stock LP in stock location, pusher on the rail, regulator capped at 15psi.



I'm on my 3rd LP (original VP), but it's starting to go. I've got an HP4600 waiting to go, probably will end up with a hybrid (not THAT kind of hybrid!) Vulcan relocation kit to plumb in with my stock LP + HP4600 + my Wildcat Maxflow kit.



Thoughts?



Tim

 

[BlackburnR]

Try a new overflow valve. The new vp44 does not come with new one like older inline and distributer pumps. This got my psi to 15psi at no load and 11psi wot.

 

[ThrottleJockey]

See my sig for my fix.



Dave

Here comes Dave wavin' that camshaft around again. :-laf

 

[nps]

Here comes Dave wavin' that camshaft around again. :-laf

Sure that's a camshaft he's gripping tightly? :-laf

 

[ThrottleJockey]

Sure that's a camshaft he's gripping tightly? :-laf

:-laf :-laf :-laf

 

[Short Stack]

Thanks guys for the reply's! Ok FASS owners, how many trouble free miles on your fuel system?

I have about 45,000 or 50,000 on my FASS, with same filter and idle 15 /16 psi wot 13 psi, just can't keep the VP44's??

 

[MMoyle]

Well... . I put the campaign pump in the stock location along with the in-tank pump today. I am getting 25psi at idle and 18psi at WOT. I am going to keep this setup for a while and see what happens. Based on my research, I don't "think" I will have a problem with too much pressure. Time will tell..... Let's see how long this setup lasts.

 

[isb360]

BlackburnR, tell me more about the overflow valve. Where is it? Easily accessible? Does it really limit max psi in VP? If so, then no one running high pressures should ever have diaphragm problems. I was thinking of a gasser V-8-style Fuel Pressure regulator. Just a thought.



Tim