Rokcrlr

Can someone tell me what exactly is bad about the vp44 What causes it to fail, remedies and Why in the world do they cost so much to rebuild, IS itlow lift pump pressure?I'm looking at a 2000 with over 250,000 miles and the guy said he has never had any troubles with it, but they engine was rebuilt 3 years ago beause is kid tried starting it with ether after it ran out of fuel. Looking at this tomorrow,sat the 3rd and tring to learn All I can
Thanks

RickCJ

Low lift pump pressure, dirty/water or not enough lube in the fuel cause mechanical break downs. Heat cycles cause electrical problems. They cost so much to rebuild because you have to be authorized by Bosch. The tools cost a lot of $$$$.
Some rebuilds are better than others just like a rebuilt engine. Buy from a well known rebuilder!! Cost $1000-$2000.
If you're not familier with diesels take someone who is with you or test drive it to a good diesel shop to have it checked over.
250k isn't much on the engine but the trans and running gear will need some attention!

scook6

I have the same questions as you do. I called a company that rebuilds VP44s and asked them how much would they charge to rebuild my own pump? Their answer was they don't like to rebuild your pump, they want to sell me a rebuilt pump and asked me why I would want to have my own pump rebuilt? My answer was I want my own pump rebuilt because I know where it came from and I know what has been rebuilt on it because the company has to give me a list of what has been done to it. Then I asked what it would cost to rebuild my pump? They weren't in the mood to give an estimate at that time. So I talked to another company, and they were happy to do my own pump and said they would only charge me for what was bad in the pump. If you don't mind your truck being down for a few days this might be an option for some people. Just my two cents.

Junk Man

Who is going to rebuild yours?

John DiMartino

If it went 250K with no trouble,it must be a good one! The 2000 was a good yr for VP44's.Mine (knock on wood) is perfect,over 130+ K on it,and lots of hard miles with drag comp.Lift pump pressure can be checked at the injection pump,there is a schrader cap(drivers side of engine,follow fuel line from bottom of filter housing to inj pump inlet,put a low pressure guage on there.You should have 12psi min idle and 8 WOT.

Bart Timothy

IMO, it is Cummins' decision to power the lift pump straight off the ECM and mounting it on the engine block, that are the biggest reasons for lift pump and VP44 failures. These cause rapid fuel pressure hammering which destroys componants, and electrical spikes which destroy curcuits (from running a 5 to 6 amp brush type motor off the sensative electronics of the ECM). Each condition amplifies on the other, until the system self destructs. A boucing fuel pressure guage is a good indicator of future VP44 failure.

The largest mechanical failure point of the VP44 is high pressure chamber o-ring or diaphram failure, and sometimes timing piston siezure, which cause the 0216 code to be thrown. Lack of fuel preesure has nothing to do with these failures, but rapidly pulsating pressures do in the case of o-rings and diaphrams. Examination of failed o-rings shows they look to have almost been beat with a hammer. The diaphrams crack out from fatigue. Timing piston siezure can be caused by contaminated fuel.

A completely dead lift pump, or obstructed fuel inlet, will throw the 0216 timing code because of total lack of fuel pressure in the high pressure chamber, but not necessarily killing the pump, again, leading to the myth of low preesure being a VP44 killer.

Early on in '98 and '99, there were head and rotor siezures caused by poor machining, which started the whole myth of lack of fuel being a big VP44 killer. While fuel is necessary for lubrication, only a couple of pounds pressure is sufficient, unless you're after high performance.

VP44 electrical curcuit failures are also common. Fueling boxes will cause the timing solenoid to fail from being pushed past its duty rating. For that matter, the introduction of any foreign into the sensative electrical curcuits can cause problems.

Lift pump failures are almost always from internal bypass valve failure caused by rapidly pulsating pressure, which hammers the valve to death, causing loss of fuel pressure.

The VP44 enjoys a good reliability reputation over in Europe, where it is used on a half dozen different V6s without use of any type of lift pump. By the very design of it, these engines are running negative fuel pressure.