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Cummins2001

VP44 problems ?????

50 posts in this topic

Ok. I see you guys say 20-15 psi on fuel pressure is good. I got some gauges and it reads 10psi at idel and 5-6psi WOT. I thought maby I hooked up the gauge wrong and so I did it again and I am sure its right. Now what do I need to do. Truck never studders and starts good hot or cold. Truck runs good really if I did not have gauges I would not be able to tell the difference. I dont want to run the VP low on fuel since that all that lubs it. What should I do?

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get yourself a new transfer pump asap.

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Would you recommend stock or aftermarket transfer pump. Is the transfer pump also called the lift pump?

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Get the after market pump, and do it once, before you blow the VP at $1000.00 +.

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I am looking at a FASS lift pump that replaces the stock pump. Is this a good lift pump? They want $275 for it. What other brands are there?

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I am looking at a FASS lift pump that replaces the stock pump. Is this a good lift pump? They want $275 for it. What other brands are there?

NO!!! What you are looking at from FASS is the DDRP pump - it's not any better than the stock pump. FASS pumps are good except for the DDRP. If you can afford it go with a full FASS with air separator and filter. Otherwise look at a Raptor or AirDog. You want your pump located near the fuel tank not on the engine block.

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The fass is actually a ddrp 2. I am thinking I want to go with the raptor just because it has adjustable fuel pressure screw. Its alittle more expensive like $380. I think thats the way i am going to go unless they have big problems with them also.

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From everything I've read Raptor is a good pump. Lots of folks have them and are happy with them.:thumbup2:

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Thats good I think it will be a good system. What advantage do you have with like the air dog with the separate filters?

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Thats good I think it will be a good system. What advantage do you have with like the air dog with the separate filters?

Air/water separation from the fuel, better filtration of the fuel than the factory setup, ability to bypass the restrictive factory filter and small fuel lines.

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NO!!! What you are looking at from FASS is the DDRP pump - it's not any better than the stock pump. FASS pumps are good except for the DDRP. If you can afford it go with a full FASS with air separator and filter. Otherwise look at a Raptor or AirDog. You want your pump located near the fuel tank not on the engine block.

Hmm, I located mine under the hood by the engine where it is high and dry, instead of underneath where the winter road slop can corrode it. I Get 23 PSI at idle, if you have no air leaks, it should not matter where you mount it.

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Hmm, I located mine under the hood by the engine where it is high and dry, instead of underneath where the winter road slop can corrode it. I Get 23 PSI at idle, if you have no air leaks, it should not matter where you mount it.

I disagree, but to each his own. It's much easier for a pump to push a column of fluid than to suck it. look at the specs of pumps where they show how far it will draw and how far it will push a vertical column. That's why water wells have submersible pumps not one at the top of the well unless it is a shallow well. As far as putting the pump by the engine because it is better protected, that is a good point, however it is easy to put in a splash shield on a frame mounted pump.

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I disagree, but to each his own. That's why water wells have submersible pumps not one at the top of the well unless it is a shallow well.

I would not call less then 2 feet a deep well :lol: If a Fass 95 is not capable of that, I am going back to the OE Carter that is capable. It actually primed it self very quickly on 1/4 tank of fuel, with no fuel in the new lines. So the pump is very capable of pulling the tiny bit of lift, and 23 PSI is proof of that. My pump would have to be 9" from the ground to have 0" lift on the intake side. But sure a pump that needs no prime is best situation.:thumbup2:

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Simular case... I'm not exactly right up against the tank either but hidden behind the transfer case so the skid plate protect the filters and the pump is shielded from flying debris... If I crack the fuel line at the pump inlet I get fuel flow siphoning effect is really good... :thumb1:

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Simular case... I'm not exactly right up against the tank either but hidden behind the transfer case so the skid plate protect the filters and the pump is shielded from flying debris... If I crack the fuel line at the pump inlet I get fuel flow siphoning effect is really good... :thumb1:

Are you guys sure its my lift pump going out. Is there anything I can check to make sure its not something else. I sure hate to buy a lift pump and that not fix my problem:ahhh:

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Your lift pump is the only thing creating the pressure, and unless you have fuel spraying out of a line somewhere, it is the only cause. Your problem is one of the most common problems for any 24V owner, and it all falls back to the crappy OEM lift pump. If you still have doubts, test your lift pump. http://mopar.mopar1973man.com/cummins/2ndgen24v/lift-pump-diag/lift-pump-diag.htm

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I have not noticed any fuel spraying out anywhere so I guess it is the lift pump. How long can you run low psi to the injection pump before you hurt something? Like I said in the begining I thought the fuel pressure sending unit went bad so I had drove it for like a couple week like it is now. Hopefully I did not hurt the VP :pray:. From what I can see the raptor lift pump comes with the big line kit. Is that correct? Does anyone have the raptor? How does it perform? Any problems? How easy is it to install?:shrug: Thanks

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Not sure on the second half of your question but as for the first half, your basically just saying can I make it to town 30 miles away on the gallon of gas I have in my tank... It might go another 10,000miles, it might go to the end of the driveway. The electronics seem to be the determining factor and are cooled by the fuel which needs 14psi to cycle through the lift pump adequately enough to be flowing cool fuel the entire time. There is some good reading on it here http://forum.mopar1973man.com/showthread.php/1656-VP44-Write-Up-Minimum-pressure-suggested... You might not have hurt it yet, but 10psi is the bare minimum, with 14psi being the preferred minimum, and your saying that you have dipped below even 10psi.. Either way, your lift pump is not doing it's job any more.

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I have the raptor w/big line kit.works very well mounted near tank. only problem you might have is how to draw fuel from tank. I installed a draw straw.

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How hard was it to install the draw straw? Do you have to drop the tank?

---------- Post added at 09:46 AM ---------- Previous post was at 09:38 AM ----------

I have the raptor w/big line kit.works very well mounted near tank. only problem you might have is how to draw fuel from tank. I installed a draw straw.

I read somewhere about the raptor does not need an return line? Isn't that the way the injection pump keeps cool by cycleing fuel throught the overflow vavle back to the tank? If I do away with that how is the pump going to keep fuel cycleing through the pump to keep it cool? :shrug:

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I assume you checked the fuel filter?

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Yep that was the first thing I did and then I replaced the FP sending unit.

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Fuel pressure normally tells the full story for you... Like mine is 17.5 @ idle and no lower than 15 @ WOT. Now with my old Carter pump typically I saw 14 @ idle and 12 @ WOT. Once if fell to 11 at WOT it was time to change... Being the factory lower limit is 10 PSI... Stock carter lasted about 9 months to 1 year if you lucky... So get a fuel pressure gauge, change your filter, and check for air leaks...

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Fuel pressure normally tells the full story for you... Like mine is 17.5 @ idle and no lower than 15 @ WOT. Now with my old Carter pump typically I saw 14 @ idle and 12 @ WOT. Once if fell to 11 at WOT it was time to change... Being the factory lower limit is 10 PSI... Stock carter lasted about 9 months to 1 year if you lucky... So get a fuel pressure gauge, change your filter, and check for air leaks...

I have got a fuel pressure gauge and I just replaced the fuel filter to see if that was the case.

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