Engine/Transmission (1998.5 - 2002) Extra lift pump problems

[czahnle]

I lost a VP44 a few weeks ago. Two thousand miles before I had put on an extra Carter push pump at the tank. I bought a kit from a fuel injection outfit and it said to run a wire from the stock wire at the stock lift pump to the new pump.

My truck has 96000 miles on it and never had any problems but I wanted to make it better. (No good deed goes unpunished) When I was testing to find my failed VP44 I found that I was getting a lot of air in the fuel. I found my stock lift pump had failed.

After replacing the VP44 and bypassing the stock lift pump and running only a 18psi Carter at the tank I am doing okay. However I found that the Carter replacement pump says right in the directions to use a min. of 14AWG wire. DC harness to lift pump is 18AWG! I put in a relay triggered by the 18AWG wire and am running 12AWG from the batt to the pump.

I think running two pumps from one 18AWG wire burned out my stock pump which took out my VP44. A person could even run two pumps from the same relay if you wanted.

Just my thoughts.



Chris

 

[Steve St.Laurent]

Did you test the main pump before you added the pusher? The reason I ask is that it could have been failed already. That being said you definately had too much load on that circuit running two pumps off of it. The ECM is what feeds that and in my experience the OEM's put the bare minimum gauge wiring, etc on anything electrical to save weight and cost and any additional load is going to cause issues. I was one of the early adopters of using a pusher pump around here and I recommended from the get go that you used a relay and trigger that relay with the primary fuel pump wiring only.

 

[Steve Campbell]

Perhaps where I am going with this is beyond your immediate problem. You stated... "When I was testing to find my failed VP44 I found that I was getting a lot of air in the fuel. " I noticed this phenomenon with my truck a number of years ago. I have 4601HP Carter back by the tank with no factory pump now. I also installed a "bypass" on the pre filter plug on top of my filter housing whereby I return a small portion of the fuel to the return line and back to the tank. I just have a "screw valve" that I open enough to keep the pressure "below" 12 lbs so as not to use the internal valving in the pump (a lot of them were failing for this reson) and to "eliminate" that air before it got to the VP44.

 

[czahnle]

Dear Steve and Steve,

When I installed my first push pump I also installed a fuel pressure light. (a gage is nice but does not tap you on the shoulder like a light) The light comes on at 5psi. I also changed the fuel filter and saw I had the normal amount of volume and the light would go out after a second or two of the pump running. I drove it over 2000 miles before it failed. I don't think my stock pump was out when I put in the pusher pump IMO. I will now test for air and volume at every filter change useing a vinyl tube from the clean side of filter into a 1/2 gal. milk bottle. It should 3/4 fill the milk jug in one 25 second cycle bumping the starter. Of course you can see any air in the vinyl tube. As for pressure I have a test set with fitting and gage.



Thanks for both of your help.



Chris



I saw one of your earilier posts regarding a relay Mr St. Laurent and that put me on the right track with the relay. To bad I saw it after my VP44 failure.

 

[canblue]

I have installed a secondary pusher, Carter unit from Piers. I am still concerned about the drop out of either pump. Is there a way, electrically, to monitor the status of the pumps? Can we hook in a LED to indicate an "ON" status or something along those lines. If the pump is dead would it still draw current?

 

[Steve St.Laurent]

It could canblue. I recently had the engine mounted pump on mine die. I could tell by the loss in fuel pressure. I then troubleshot it by unplugging the pusher and got 0 pressure from the main pump.