Engine/Transmission (1998.5 - 2002) "why me" lift pump question

[TowPro]

Ok, I finaly got time to hook up my lift pump



Aeromotive Street Rod fuel pump. The info I have says 18-20 psi.



Turn the key on, several "bumps" to clear the air out, and boom, the gauge goes up to 40 psi!:--)



Now what? I can call Aeromotive on monday morning, but this sucks, I got to leave Thursday night with my camper!



Anybody used one of these pumps and had to turn down the pressure?

 

[MikeR]

Nobody else has used this pump yet. For the last six months I have been planning to use this same pump, just waiting for my current carter pump to die off. Sounds like an inline regulator needs to be used.

 

[TowPro]

someone is using one, but with a regulator. BUT this is the words from the engineer at Aromotove



"you will see dead head pressure of 18-20, and free flow of around 150 psi (with no pressure)" . This max pressure of 18-20 is because this pump has a "releaf spring" much like our stock pumps, when it hits 18psi, the extra flow is directed back through the inside of the pump to the inlet I explained our application and I could tell this was not the first Cummins guy that called, he said "you will see around 15 psi with our pump in that system"



I called Jegs they said "return it and we will replace it", but because of the time crunch (going camping next week) I had to buy another one and they will credit me when they get this one back.



Now I am running this pump into my exhisting lift pump, which has a bad pressure valve.

With both pumps running I see 40, so just for the hell of it, I triggered the relay so just the back pump runs, still have 33psi, at the fuel filter, which is after the stock lift pump that was not running. Somethings wrong with this pump.



Tomorrow I may bypass the stock pump, and see what PSI I get, but still, this pump should not put out more then 20 psi if you were to stop the flow all together.

Originally posted by MikeR

Nobody else has used this pump yet. For the last six months I have been planning to use this same pump, just waiting for my current carter pump to die off. Sounds like an inline regulator needs to be used.

 

[MikeR]

When I do my install, I'm going to use the Hot Rod as a stand alone pump and get rid of the stocker. I bet that will be a big difference from what you are seeing. It's too high a pressure for use as a pusher pump(in a 2-pump sys), since this pump is capable of 150gal teamed up with a carter capable of 90gal.

 

[TowPro]

late last night I went out and did another test.



I still am checking fuel pressure at the fuel filter inlet



I disconnected the stock liftpump, and jumped the relay on the pusher pump. All that was running was the pusher.



33psi with motor not running. Is 33psi safe to drive with?



That 33psi was the pressure at the filter, with the pusher pump pushing through the front lift pump, which was turned off.



This pump is sopossed to do 18-20psi "dead head", even 33 makes me think the releave valve is not opening.

Originally posted by MikeR

When I do my install, I'm going to use the Hot Rod as a stand alone pump and get rid of the stocker. I bet that will be a big difference from what you are seeing. It's too high a pressure for use as a pusher pump(in a 2-pump sys), since this pump is capable of 150gal teamed up with a carter capable of 90gal.

 

[csutton7]

you need the Aeromotive regulator designed for the pump---install it between the filter and VP44 and run a separate return line back to the tank--you can either tie into the existing return line--I'm not sold on this yet, but some guys are doing it--I cut the rubber line on the filler neck overflow and teed into it-----chris

 

[TowPro]

the regulator I see you guys running shows in the books that it has a vacuum line going to it, to regulate pressure as boost (or vacuum) increeses (on gas engines).



what do you do, just leave that port open?



Is there a return style regulator out there that don't have the added cost of the vacuum regulator?

 

[Bigsaint]

There's no need for a vacuum regulator. Here's the one that Chris is running, I believe AEI-13301. That's a Summit racing number and they are back ordered. Maybe Jegs has it in stock.



Scott W.

 

[TowPro]

that number is the one I was looking at. At Jegs it shows "Fuel pressure will rise on a 1:1 ratio when referencing boost "

Makes me think there is a vacuum/boost.



Well today I build the stock pump bypass system, and remount the new pump on a rubber mount (its pretty loud when hard mounted to the frame)

Originally posted by Bigsaint

There's no need for a vacuum regulator. Here's the one that Chris is running, I believe AEI-13301. That's a Summit racing number and they are back ordered. Maybe Jegs has it in stock.



Scott W.

 

[TowPro]

Well just finished the install.



Aeromotive Street Rod fuel pump in the back by tank, feed through the standard 3/8" line that comes out of the tank (I feel this is gravaty feed after the fuel lines are perged of air because of syphon as the pump body is level with the bottom of the fuel tank level)



Front Pump bypassed.



Idle 24psi, running 20psi. Have not driven it yet, I broke a hose clamp and need to find another one to stop a small leak on the outlet of the pump.



Now I wonder if I can get rid of the relay since I am no longer using the front pump? I can test the amp load of the rear pump but it would be a PITA to test the front one. I guess if I have hard start problems, I could always wait for the fuel pump to quit running, then start it



Do you think 24psi is to much? I have read Steve's post of the past Look near bottom of this link



Sure wish this pump only did the 18-20psi they promised. I have another one comming from Jegs as I thought this one was defective (adjusted to high from factory) but I have to call Aeromtive first to see if they will tell me how do turn down the pressure, or drop another bill on the regulator, but I don't feel I have to if I can get 18-20psi (or less, I would really like 14-16psi) out of this pump by adjusting the releaf spring.

 

[TowPro]

Damn, I can't win My leak turned out to the the new Aromotive pump leaking out the motor! I got a new one on the way from Jegs, but still. I guess the pressure releaf valve was bad, which in turn took out the seal in the pump?



Hurry up and wait. The worse part is the pump will be here Wed night, then Thursday night I leave with the RV for a 1. 5 hour run, talk about "testing by the seat of your pants"

 

[Bigsaint]

Sorry to hear about the pump. Does it have an external dead head adjustment on it's exterior ? The Mallory 4150's I had been running did, it's adjustment ( always do while the truck is running) was counter clockwise to lower the psi's. The offer still stands on the Mallory, I could next day or overnight it to ya for the trip and you could send it back once you get back when you get the Aero pump installed.



Scott W.

 

[Pit Bull]

Originally posted by TowPro

Damn, I can't win My leak turned out to the the new Aromotive pump leaking out the motor! I got a new one on the way from Jegs, but still. I guess the pressure releaf valve was bad, which in turn took out the seal in the pump?



Hurry up and wait. The worse part is the pump will be here Wed night, then Thursday night I leave with the RV for a 1. 5 hour run, talk about "testing by the seat of your pants"

Go to Cummins and get a new lift pump for this trip. When you get back you can sort this problem out. At least get the lift pump from cummins and take it with you as a back up incase you have a problem. Then return it if you don't need it. JMHO

 

[TowPro]

followup

Finaly got a hold of Tech support at Aermotive (he was away at a race).



If you were to plug the output of this pump, and put a gauge on it, you should not see anymore then 18-20psi because its internaly regulated. So I asked "then why am I seeing near 30psi?. he said "We use Locktite to lock the pressure adjustment screw, and some may have gotten on the pressure valve, Turn the pump on and off a couple times and it should break free". Then I told him its also leaking fuel. He said he was very sorry I experenced problems with his product, in fact the pressure probably blew out the seal.



After talking with him for a while I decided I could use this pump without a regulator and I would see 18-20psi, BUT by using the by-pass regulator, the pump will be under less load (I will use 15psi) and last longer (something we all want to hear!)



I will be installing the parts Wed night when I get home.

 

[TowPro]

first sorry about this long thread.



I got my new Aeromotive lift pump AND regulator this time. Hooked it up, started her up and dialed it right into 14psi.



Then the New Aeromotive pump started ******* diesel out the motor drain hole



THE HELL WITH AEROMOTIVE!!!! I called Cummins in Harrisburg, their open until Midnight, so I went up and picked up the latest rev pump from Cummins for $160. 00



Dam aftermarket junk!



Now I got to take tomorrow off from work to finish the job so I can go camping this weekend. Look at the bright side, I now have a 5 day weekend, and I really don't mind working on the Cummins

 

[Chipstien]

Sorry to here about the problems.

I would suggest that when you get back from your trip, move the stock lift pump back buy the tank.

 

[rbattelle]

My Aeromotive just started leaking out the bottom plate that seals the pump housing. .



-Ryan