ScreaminEagle

I am looking at adding an XZT+ and maybe 275 injectors. Is the VP44 just a poor design? Has this been a problem from the beginning of the 24v engine? Is there a certain mileage to rebuild or replace the pump? What affect will an XZT+ have on the VP44?

I see a lot of people refer to the VP44 so I'm trying to educate myself.

JHew84

Well you have a lot of reading ahead of you, there's a ton of posts out there that will have far greater detailed answers but here's some summary's:

1) it's not really the VP44 being a poor design, rather the lift pump wearing out too quickly which causes the VP44 to strain trying to keep up with the fuel needs.

2) Yes, the VP44 came about with the 24v and it has been an issue since 98.5, if you want a 24v it's something you'll have to deal with (but what vehicle doesn't have something that needs to be dealt with?)

3) No particular mileage, some people lost their pump within the first 10K miles, others seem to have 300K on the original. Basically to me seems like luck of the draw and proper maintance, some sort of combination...

4) From just about everything I've read the performance modules really do not make the VP44 any less reliable. Keep it fueled and cooled and it should be good to go. You'll want to get a FP gauge to make sure the LP is still operating at a reasonable pressure though, that seems to be the achilles heel of the whole system.

Hopefully that gives you an idea, but seriously go read some of the posts on here, there's A LOT of good info to be had!

'strokeThis_'07

Check out this site-lots of info...

http://www.bluechipdiesel.com/vp44diagnostichelp.html

J OOPS

Yes there is a manufacture fault. They won't admit it though. All the rebuilt pumps have fixed the problem,,,, if its from a reputable rebuilder. The problem has been in the timing advanced solenoid cylinder/bore was made out of a bronze alloy that was pressed into a aluminuim housing of the pump and the valve is made of steel. The bronze alloy is to soft and also expands to much and gets scored by the steel valve in it causing dead pedal when cold, once the bronze expands from heat then no more dead pedal. Also because of the bronze if you are constantly driving at a certain speed say 65 the steel valve scores a ring into the soft bronze, what happens then is the valve will start to hang up and cause a dead pedal around 65. The fix was replacing the bronze with a steel sleeve that wore equally with the steel valve.

bullboy85

ok this has confused me even more, i have realy poor milage, and some lost power. the power is inconsitant too. i just had a load of about 20k on my truck. some hills the truck would take like they were nothing, and them some hills that seemed smaller it would strugle or when the ground looked flat i was suddenly haveing to downshift to keep up. i was told it was probibly the vp44 but according to this it doesnt sound like thats my problem???????????

J OOPS

Poor fuel milage, intermitent loss of power yep your VP44 is going, the valve in the bronze bore is sticking, its not allowing the pump to advance properly.

bullboy85

im getting 11-12 mpg, regular driving iv been working to get it better, already dumped a ton of money into it, any way to be sure before i go a rip it out to be rebuilt with out taking it to a shop where theyll chage me $100 just to say "yup thats your problem"?

J OOPS

Check and see if any codes come up or rent a scanner your self. I get 23.5 mpg but I installed a part time hub kit (custom made) that helped out the fuel mileage. Before that I was getting 18mpg, when my vp44 started going out I had the dead pedal when cold and at 55mph but I also had intermittent loss of power and loss of fuel mileage. Replaced both pumps and got back to 18mpg. With the part time hubs it jumped to 23.5. Part of the increase could also be to a tranny shift kit and running synthetics, I did that all in 2 weeks before I did the fuel mileage check

bullboy85

id like to do the hub kit too but got to get this thing right before i do it, im hearing most people are getting atleast 16. best i think iv done sence i got it was 15 right after i got it. im just not notesing that dead pedal, maybe what im thinking is just the truck warming up it the dead pedal ur talking about, but i havent notesed it at 55-60 eather.

bullboy85

ok new one, just drove my truck, with in half a mile down the road it died like it was out of gas, lift pump wouldnt run just like the time i ran out of gas. truned the key off and let it sit checked the pump it ran, primed it and it started... what the hell was that about? getting low on gas but not out still 1/8 of a tank???

Valv

I would never run my tank less than 1/4 full, chances are there's some "junk" at the bottom and will clog my filter. I buy used trucks, I never know what was the previous owner doing, to take less chances early filter change is my goal. No sense saving $ 10.00 for a filter to throw $ 1500 in a new VP44.

Also, not to be "picky" but my truck doesn't run on gas, it's a diesel.

CTD_Neil

No problems here and I'm at 106,000 miles. Truck has had a wire tap box most of it's life. One thing you need to remember is you'll always here the bad side on forums but rarely the good. It's much more common to post a thread titled "My VP44 Died" than to post one titled "My VP44 is just fine after 106,000 miles"

bullboy85

when i did my fass i also put in the new pick-up tube and comleatly cleaned my tank so i havent been as worried about filling it up before the light comes on. when i ran out of diesel i wasnt paying attention and didnt relize after i installed my tube that it wont go all the way down to the E.

ScreaminEagle

My truck has 142k and it's never been touched. But, I put a BHAF and 4" exhaust and soon to have and XZT+.

Does a fuel pressure gauge measure the injector pump, or lift pump?

BigErksG2

it really depends.... there are fuel pressure gauges that are for the lift pump 0-60psi usually and there are rail gauges for the injection pump that measure pressures up to 30k psi. Thats more pressure than a laxitive joke during a ride on the turnpike.