Can VP Fail Even Tho' Good Pressure?
 

Hi, Just wondering if the VP44 can fail even though you've got good fuel pressure? I have a Raptor 150 that pushes very good pressure; just wondering if consistent pressure helps prevent the VP from going bad...idunno (pardon if dumb question)[duhhh].

it may help some, but it WILL fail because that is what they do[laugh][coffee]..........all vp44's fail

johnh, Thanks (sigh)... Appears your VP lasted up to 181K; any idea why it failed (other than age), and did you do anything extra to keep it alive that long?

early VPs failed from all kinds of things the new ones are mostly electronics burning out ,I was told that they have a key stroke life span some last longer its the luck of the draw if you get a long runner. my VP is near 150k miles orig.

yes they can.

It seems that the general consensus is leaning towards the computer chip which controls it and the number of heat cycles it goes through. Apparently the EPA requirement of non lead solder is biting us in the tailpipe, or wallet.

Lots of good info here.

BTW - not a dumb question at all.

Yes they can.

I'm on pump number 4 right now. [tapdshut]
Never had less than 12 psi at WOT.

the electronics failed.........i use 2cycle oil most of the time,currently I'm using WMO

WMO...I've heard of folks using that. Do you strain it (how; what do you use to strain it)? and how much do you add per 30gal tank?

Its not uncommon for guys to replace their stock lift pump with an aftermarket fuel pump and then have the factory VP quit shortly after. Call it coincidence or the fact that most guys dont bother to change to a better fuel pump until they've already replaced one or two LP's before and/or they've just found out that they had little to no fuel pressure and are hoping that a new fuel pump will restore the damage done. Plus their VP probably has more than a few miles racked up on it too.

The VP electronics need to stay cool because of the asinine reason that Bosch opted to use lead free solder in the computer which deteriorates under high heat situations, causing intermittent connections, and eventual failure. Running fuel pressures above 14-16 psi which the overflow valve is set at will assure that the VP always has fuel running through it, keeping it cool(er) while the engine is running. But after the engine is shut down then the engine heat soaks the VP, getting it hotter than it should be. This is the heat cycle problem which is why the VP is called a time bomb, because no one knows how many of those "heat cycles" it takes for the computer to short out. Plus the ambient weather is a determining factor. Also, if the VP is a re-manufactured unit then all the internals are the updated versions which means its fully capable of handling ULSD. But if adding any lubricating additives makes you feel better than by all means.....

Blue Chip has an answer for the heat soak problem.

Can you provide the link (URL) to their answer?

Not that I've heard.....and I've talked to the Chip many times too. He's got idea's on how to possibly deal with the heat soak issue but nothing he's marketing.

Bingo.

Fuel pressure is NOT the cure for VP failure, and absence of such is not the *cause* of VP failure.

In the 12 years+ that the VP trucks have been on the road, no one has YET proven that low fuel pressure causes the VP to fail.

JH

Huh????? Not trying to put you down HOHN but there are hundreds and hundreds of posts on many diesel forums proving that lack of fuel pressure is the exact reason why the VP failed. Sure the early VP versions, up until around 2000, had some internal parts issues, and also lack of attention to detail issues, which both caused various mechanical failures. And then there's going to be just the run of the mill cases too where something simply just broke, but for the most part its always been because of lack of fuel. Now excessively high fuel pressure has NOT been proven to be an issue although the general consensus at the moment is that anything over 20 psi is just not necessary. Clearly since knowledge of the VP is minimal for most, you see guys swapping out their VP trying to fix another issue, and thats an expensive guess. I think the real problem you see comments like "VP's just fail" is because we have all been led down an uninformed road by Bosch and because the VP44 was a temporary fix for the Cummins ISB until Cummins finalized the common rail system which means that Bosch never intended on helping solve the issue. Maybe Bosch and Cummins didnt think the VP would become so popular and stay on the road as long as it has. So for that reason we have been forced to find the problem ourselves by trial and error. And really the only ones who are going to try to find anything out are the ones who rebuild them and the aftermarket guys who want them. Other than that, not to many people have the ability, time, or money to tear into their broken VP and keep tearing into anymore VP's which happen to fail on them since the core charge alone is almost the same cost as the VP itself.[laugh] Really.....how many people actually care about the VP issues anyways who doesn't have a VP truck? Probably not to many. And lastly.....all parts fail.....even the P-pump and the CP3.

i didn't strain it, i just drained it in a clean container figuring my 2 micron racor fuel filter would take care of any thing my engine oil filter didn't.......i put about 8 quarts in 80 gallons (my fuel capacity)