frank1981

1998 ram
4x4 24v

OK, I've got a really bad problem. I bought the truck from my uncle, because the vp44 was out. I put a new one in myself, but it had no power and didn't like to start. I took it to cummins and they changed the boost sencer and also told me that my two day old pump was bad! The place where I baught the pump was nice enough to change it for me for free but by the next day it was starting hard again........ So what im wondering is am I haveing really bad luck by getting two defective pumps or can there be something breaking the pumps... Cummins tested the lift and said it was good and I also installed a 4lb warning light. I'm out of ideas..

Thanks for any help

Frank

ratsun

Are the pumps your putting on new or remans? I have heard of some poor track records for some rebuilders. I would say that if Cummins tested your lift pump and it passed their flow and pressure test your having bad luck with VPs.
I dont know if anyone has nailed down the VP thing yet but from the stuff I have read there are 2 types of failures electronic and mechanical. I havent yet heard any one come up with the trucks electrical system causing failures. Hopefully one of the experts here will chime in and shed some light on this for you. Good luck

justinp20012500

Sounds like you have a leaky line. The pressure will slowly bleed down causing longer crank times. Just my expierence playing with the Vp and lines...

mysing418

Check the lift pump operation and fuel filter at once! Lift pump not workin, fuel filter plugged the VP44 dies a shrot life!

frank1981

It's a new filter and the lift pump was tested by cummins and I installed the 4lb warning light. But I bought a lift pump today. Will put it on before i drop the truck back off to the shop.

phox_mulder

I 2nd that diagnosis.

Check the fuel sender in the tank, all lines from the tank to the lift pump, then to the VP44, don't forget the return line from the VP44 back to the tank.


phox

frank1981

How do I check the lines for leaks? I'm guessing by looking for leaks or wet spots? Or by doing some kind or presure test?

Thanks


Frank

phox_mulder

Either way.
You can pressurize the tank, and that will aid in finding leaks between the tank and the pumps,
but won't help much between the pumps.

Often, it is a very small pinhole or crack that you can't see, but is just enough to let air in as the lines depressurize after shutdown.


phox

frank1981

You guys are very helpful! I will check first thing in the morning when I change the lift pump. I will keep you posted.

Frank

frank1981

Well I changed the lift pump today. I couln't find any leaks but it is snowing out and I left the truck sit for over an hour and it fired right up. Looks to me like it was a lift pump problem to me. Is it possible for a bad lift pump to loose the prime?

Thanks
Frank

frank1981

Well I let it sit over night and it took a really long time to start it...... I guess its back to the shop.

travjrath

three things -
1- the line between the filter and the vp, check or just replace

2-the return line banjo bolt/relief valve and its line

3-the rear seal in the vp 44 itself , i had 4 reman pumps with the seal bad , and there was a leak there on all of them ( from a tiny drop , to a steady stream ) all caused hard/ delayed starting

these are all things that have caused the problem you speak of , on many of the trucks ive worked on

ratsun

One other thought, did you replace the Banjo bolt washers? Maybe ones leaking a bit. Good luck

frank1981

/


yes, at the vp44 and the lift pump.

mysing418

You installed a new fuel filter too didn't you? Make sure filter o rings are seated correctly...