The Diesel Garage banner

1 - 20 of 20 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter #1
im new to the scene but ive studying diesels for a while but what is a lift pump and what does it do?
 

·
Registered
Joined
·
316 Posts
The lift pump pulls fuel out of the tank and feeds it at positive pressure to the injection pump. On your truck, LP failures are very common and usually result in Injection (IP) failure as well.

New? Welcome. Now go and get yourself a Fuel Pressure gauge so you can keep tas on your LP. Even under stock power they fail like crazy.
 

·
TDG Mafia Member #21
Joined
·
1,345 Posts
:whs You definatly need a fp gauge to keep uour injection pump healthy.
 

·
Registered
Joined
·
5 Posts
I dont wanna start a fight but I disagree. Ithink the first step is upgrade the fuel system. At the very least an aux lift pump and low pressure light.My fuel press with this setup is 18 psi at idle, and I have not seen the light come on yet.With the smarty and quadzilla I can, and regalarly do, rev this combo to 34-3500 rpms with no fueling problems.If Ineed to upgrade after my injectors it would be to a cam and mechanical pump.Just my narrow minded opinion.
 

·
TDG Mafia Member #21
Joined
·
1,345 Posts
I agree with you to a point. I would only say that you don't need to replace the factory lp until it gets weak. When that time comes upgrade to an aftermarket pump. If the factory pump holds good pressure it is just as good as any other pump as far as the IP is concerned. I don't really believe in spending money on things I don't need until I need them. When he starts adding mods he will probably need one but until then he could spend the money on other goodies for the truck.

That being said, If he has the money lying around.......gauges, aftermarket lp, and an intake would make nice first mods.
 

·
Registered
Joined
·
5 Posts
I didnt mean replace the lift pump, but add one to the frame by the tank.There are probably lots of kits out there I got mine from BD Power.The total $ is not much more than a gauge and mount.If you already have a box its only a matter of time (and prolly not a long time) till you have to upgrade anyways,and this will work fine even if you get injectors.Unless you are doing major hp upgrades in the near future(450+) this is the best value.Again, just my narrow minded opinion.
 

·
Senior Member
Joined
·
3,514 Posts
I agree with 99mtnram, You will need one at some point down the road. You may be able to get by with just a guage, but if you can afford it, you might as well throw in another pump and get it done with from the start. It won't cost you a whole lot more than a guage either, once you figure in the price of an isolator if you go mechanical, or the fact that an electric gauge costs $250 from the very beginning.

with that said, I would just say upgrade your fuel system completely if you have the money to throw down on it. I personally don't like the stock filtration system and would recommend getting something better, whether it is a FASS or GDP or something from aeromotive thats up to you, but it beats stock.
Sean
 

·
TDG Mafia Member #21
Joined
·
1,345 Posts
I agree with the both of you. The key words were "if you can afford it" get both. I agree 100% with that. I just think that if he can only get one thing he should get the gauge (assuming the pump is working) or at least a warning light first. A second lift pump on the rail could fail just like the factory lp because most kits use the Carter pump. I had 3 failures in less than 4 weeks when I put the Carter on the frame rail. Apparently they had a bad run on pumps at the manufacturer. I switched to the Holley and have had no problems since. My point is, I wouldn't have known there was a problem without a gauge or warning light. Just because it is new doesn't mean it is working right.

99MTNRAM......there is no such thing as a narrow minded opinion in my book. Opinions are what help us learn from each other. One of the things I love about this forum is that we can all say what we think and it doesn't turn into an arguement. That is the reason I left all the other forums I was on and spend all my time here.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #9
what kind of psi should it be running?
 

·
Registered
Joined
·
2,189 Posts
weebz90 said:
what kind of psi should it be running?
More than me......................1 psi or more.



Someone correct me if I'm wrong, but the VP44 goes out because you get negative pump pressure, the VP44 starts suckin air and because the VP44 uses fuel for lubercation. Therefore it loses lube and frys, dies, crys however you say it.
 

·
TDG Mafia Member #21
Joined
·
1,345 Posts
The vp44 uses excess fuel to cool the pump and electronics. If you show 0 psi there is no extra fuel and things get cooked. I don't know if air in the system is a factor or not. A tight system shouldn't really draw any air. The vp turns into a big straw drawing fuel from the tank if the lp isn't working and I would think that drawing air would break the vacuum and the truck would run rough or stall completely. As far as psi goes, the more the better. You should never pull the pressure below 5 psi at wide open throttle. The average pressure at idle with a stock pump seems to range between 11 and 15 psi. The important number is the lowest pressure at WOT like I said before.
 

·
Registered
Joined
·
316 Posts
You can get air from fuel sloshing around in the tank. The nice thing about a FASS . . . .



If you can afford it do both. If the stock pump is working fine, then the BD kit mounts an addition pump on the framerail and feeds the stock LP and the stock LP should not have a failure issue because it is not sucking fuel. Pumps are made to push, not pull, so when subjected to a negative pressure, they are overworked.
 

·
Registered
Joined
·
2,189 Posts
Diesel Nut said:
You can get air from fuel sloshing around in the tank. The nice thing about a FASS . . . .



If you can afford it do both. If the stock pump is working fine, then the BD kit mounts an addition pump on the framerail and feeds the stock LP and the stock LP should not have a failure issue because it is not sucking fuel. Pumps are made to push, not pull, so when subjected to a negative pressure, they are overworked.

What about the Filter when your running the FASS?
Are you suppose to keep the stock one on there or leave it off?
And would a failed stock fuel pump running with the FASS cause it do be a restriction causing the FASS to fail as well?
 

·
Registered
Joined
·
316 Posts
With the BD, you leave the stocker in place, again, if it is in proper working condition. With the BD kit it is highly unlikely that the stock pump fails because the stock pump is fed with positive pressure.

As for the FASS, Most of my customers run from the fass to the injection pump. It eliminates the stock filter and pump, and simplifies things, and this is why this is a great option when the factory pump is shot.
 

·
Senior Member
Joined
·
3,514 Posts
I agree with you on that one diesel nut. One of my friends had his FASS run through the stock lift pump and filter housing, and it worked fine. My only problem with that is you get so much more fuel by not have the Banjo bolt system.
Sean
 

·
TDG Mafia Member #45
Joined
·
296 Posts
just remember to much pressure is bad to. i think over 20psi you take a chance of busting the diagham
 

·
Registered
Joined
·
316 Posts
more likely you'l blow th eo ring for the diaphram.

BD says you can run like 30+ psi. I think no, but they said no problem. I don't know. II says 20 is the max. I like II, and they are a Bosch certified repair center. I'd keep it under 20.
 

·
Registered
Joined
·
83 Posts
We have lift pumps in stock about 50 or so. they are the stock replacement ones but we have a light kit that has a sensor, when the fuel pressure gets below 4psi it will turn on an led light that you put in your dash. A vey nice set up we have put on about 15 sofar. the light is in a nice location and no matter what pump you ever put on it it will be your saftey light. thanks Dallas
 

·
Senior Member
Joined
·
179 Posts
99MTNRAM said:
I didnt mean replace the lift pump, but add one to the frame by the tank.
At 102k miles, I had to replace the lift pump for the 2nd time. This time, I went with a Carter, mounted on the frame next to the tank. Now at 160k miles, I am still pushing 18 - 16 - 14 psi. I have an EZ on level 3 and stock injectors.
 

·
Senior Member
Joined
·
3,514 Posts
Firestorm said:
At 102k miles, I had to replace the lift pump for the 2nd time. This time, I went with a Carter, mounted on the frame next to the tank. Now at 160k miles, I am still pushing 18 - 16 - 14 psi. I have an EZ on level 3 and stock injectors.
Yeah getting a pump nearer the source will go a long ways. As stated before, pumps are more effective pushing than pulling so the less pulling they have to do the happier and longer they live. I believe the O.E. pump is actually a carter as well, its just mounted in a bad location and isn't designed to run enough pressure. Even the new in-tank relocation kits aren't that great, from what I've seen and heard they don't put out as much pressure as I would want my truck to be running.
Sean
 
1 - 20 of 20 Posts
Top