Engine/Transmission (1998.5 - 2002) How can we improve reliability for the VP-44

[dknoch]

The truck is built like a tank and the engine is unstoppable... except the fuel system problems. There seem to be plenty of good options to replace the lift pump, I have a FASS. Problem is, what can we do to improve the VP-44. Most of us probably don't have $1000+ to replace it with what is suppose to be a better pump from an aftermarket company. What about Fuel additives, some people talk about adding a fuel cooler. What are some suggestions to PREVENT these costly repairs and costly, annoying down times?

 

[FUL POWER]

Something that i think have helped me was that putting a FASS system on my truck and putting a dual trans to cool the fuel on the intake and reutrn fuel line. The big reason why pumps die i hear is that they do not get the lub and overheat. I have a drag comp and i run the pump hard and have not killed a pump yet.

 

[Nyoest]

easy, fuel pressure gauge. Keep the VP44 fuel and it should last as long as any other. There are some that would mention the heat plays the devil with electronics but if you have a sufficent supply of fuel carrying that mean ol heat away... .

 

[FUL POWER]

All i know is that i put my pump through hell and it keep comming back strong. Thats where i get my info from.

 

[keimmmo]

Most important in my opinion is a fuel pressure guage... and knowing what the pressures mean.



Additives to add lubrication or even adding oil to the fuel stands to help. Along that same line, a little Bio-Diesel adds a lot of lubrication.



I think fuel coolers make good sence... or just relocating the fuel filter housing away from the head, which is a MAJOR heat source!!! (Eliminating the source of heat is as good as cooling it after it is heated. )



I'm probably overlooking something, but these things will certainly help.



Steve Keim

 

[rweis]

I think it is a system of answers.



PLEANTY of fuel volume and pressure



Lubrication with Stanadyne PF to keep the very close machined surfaces lubricated.



A fuel cooler and relocate the return line to the tank vent to keep the fuel cool so the electronics will operate in a reasonable range. I put a fuel temp sensor on mine and typically see OAT+15* - 20* as the input fuel temp with a fuel cooler with fan and relocating the fuel return to the tank vent line.



A post shutdown blower on the VP electronics bay to positively keep the bay from heat soaking. After engine shutdown seems to add about another 20* - 30* to the surface of the electronics bay.



A kick butt fuel free water and particle seperator. I use a RACOR 690T. The CFTDR went to a couple of high pressure pump rebuilders and they showed the effects of ANY water in the high pressure pump side. Heavy pitting of any machined surface, extreme wear.



PLEANTY of fuel at good pressures (14psi - 16 psi), good water free clean fuel in, well lubricated, cool fuel to keep it cool when operating, shutdown blower to keep the shutdown heat soak off of the electronics bay.



1,2,3,4 IMHO are NECESSARY, 5 might be less so.



On a 95* day I am seeing (unloaded, 17 miles) 115* fuel input, which I do not think is too bad. Add 30* heat soak to that and I think you are starting to get into a very concerning temp range, but still safe. However, I would rather start with 115* fuel input than 140* - 150* fuel input temp like it was OEM with the OEM ff attached to the input manifold and the fuel return line to the fuel canister where the fuel pickup is which drives the internal after shutdown fuel temp over the 160* during heat soak.



By taking the OEM ff off the manifold or at least puting non heat conducting washers between the OEM ff and the input manifold you can get about 15* out of the input fuel temp. Simple, quick, low cost.



My next step is to rid the OEM ff and put an inline ff down on the frame totally away from ANY heat absorbtion and see how that does. I know the northern guys could not do that because they need some of the engine heat in the fuel in the winter. If I lived there, I would run the OEM ff in the winter as delivered from DC and a inline ff in the spring, summer, fall.



A couple of us are still experimenting with the heat issues, but just about have enough data and different approaches that we can keep the VP44 cool while running.



Bob Weis

 

[dknoch]

I have had a VP-44 fail with a pusher pump for the first half of it's life and a FASS for the second part. Good fuel pressure ALWAYS (never less than 10 psi at the tapped banjo to the pump). Just a thought... We have a freightliner ambulance with the ISB and it has about 44,xxx mile on it with no fuel system problems. It is exposed to very hard driving and long periods of idleing, often >30 mins, and somtimes a few hours. Being a rescue vehicle, it is rarely to never below a 1/2 tank giving it plenty of fuel to cool off. Just a thought.

Dan.

 

[RHARVEY]

Good fuel pressure does not always keep this ticking bomb from going off. I can tell from experience as of yesterday. The VP44 in my wifes 2000 died yesterday with no warning what so ever. The truck has a FASS for over a year now and has 1/2" fuel lines for as long as I can remember.

Yes I do preach fuel pressure. . and that is true but anything that has electronics is going to fail at sometime or another. That is just the nature of the beast. We can prolong the failure by monitoring fuel pressure and also feeding it with larger more improved fuel lines. . but when it gets tired its going to happen.

And as far as doing something to prevent it. . I dont think there is. .



Rick

 

[Duluth Diesel]

Just had my first VP replacement. LP went out and took the VP down. I want to just put a P7100 pump on it and be done with it.

 

[rweis]

Do class 8's have mechanical IP's (P7100 or equivalent for their engine) or electronic IP's (VP44 of equivalent for their engine)?



Bob Weis



There was a thread to vote on by year of failed VP44's. The vast majority were 2002's.

 

[keimmmo]

I certainly agree that we CAN NOT totally avoid VP failures!!! But, we can stack the odds in our favor. I have a late 01. 5, and the VP failed at just over 40k. The replacement pump gave more power and economy than the original one. I now have 125k on the truck and all is well. I REALLY recommend a pressure guage to avoid having a lift pump fail and taking out the VP as well!!! A guage or at least an idiot light should have been factory equipment on our trucks!!! I'll bet it would have saved the factory money on warranty replacements!



I relocated my fuel return to the filler pipe to get it even farther from the fuel pickup. While it stands to help keep the VP a little cooler, my main reason is that I run used motor oil in my fuel and it will keep the "brew" a little better mixed.



I also recommend relocating the lift pump back by the tank. While in itself it will not make the VP last longer, I think it makes the lift pump last longer... and failed lift pumps are a major cause of VP deaths.



Steve Keim

 

[SmokinJoe]

What about Fuel additives, some people talk about adding a fuel cooler. What are some suggestions to PREVENT these costly repairs and costly, annoying down times?

I have put PowerService fuel conditioner from a white jug in my truck for nearly EVERY tank and still had a lift pump and VP fail. Both in warranty.

 

[FourBarR]

so far I have dodged the bullet on vp-44. my 98. 5 which has an early version ,just passed 380,000kms today on original pump. the only things Ive done are 1- always added howes meaner to every tank. in the last year I have added marvels mystery oil also. I dont have any fueling boxes. 90 % of fuel bought at same truck card lock.

 

[Texas Diesel]

IMO, the biggest cause of failures is low lubricity fuel. Add a little 2 cycle oil to the fuel. The 2 cycle oil is 99. 9% ash free and wont buildup on the injector tips. I ran Marvel Mystery oil in my MC for a while to see what it did. All Marvel Mystery oil did is start leaving a white ash buildup on the plug tips. That is why I use the 2 cycle oil. Remember 2 cycle oil is designed to be burned.



1. Add lubricity

2. Adequate pressure, anything above 0 PSI

3. Insulate the fuel filter housing from the block (Thanks Bob!) and add a small cooler.

 

[SBall]

2-cycle oil! Hmmmm?

Hey Texas Diesel,

Your proposal to use 2-cycle oil is most interesting and I've never heard that one before. Your arguements for it's use do make sense however. Is the ratio that you use important, (ie; 1 can to a tank)? Do you feel it would make gelling more or less of a problem in cold weather? I've got many cans of 2-cycle oil that I'll never use up in my chain saw and this might be a great way to put it to good use.

Steve

 

[fox]

My truck had a fuel pressure guage since very early in its day. Never lower than 6-8 WOT, normal running was 12 +.

It also received a fuel lube every tank. It still lost the VP.



The failures are from heat on the circuit board and the fuel pulsations from the lift pump.

 

[Texas Diesel]

2 cycle oil doesnt gel, dont see how it could, no water content.



No matter what you do, the VP is mechanical and will fail from time to time. If lubricity is what you want, there is no less expensive way to go than 2 cycle oil.

 

[rweis]

On heat in the VP see my thread about keeping the input fuel temp to the VP44 LESS than 100* in ALL conditions. Also see Gary's thread about puting a fan on the VP44 after engine shutdown to keep the heat soak off of it.



I think the electronics board heat problem is a real problem, but can be avoided with cooler fuel in, and temperature control after shutdown.



Bob Weis



I also think FWIW that newer VP's have a beefier board ie the UPS / Fed Ex VP44 discussions.

 

[FourBarR]

yes 2 cycle oil is ment to be burned in a 2 cycle engine mixed with gas . dont see any reference to use in diesel fuel. however marvels mystery oil is made to add to diesel fuel and oil. we have used it in aircraft engines for 10 years with no fouling of plugs. dont mean to disagree with anyone , but since my vp44 has 380,000 kms using these addatives plan to keep on and see how long the pump will go. all the best with what ever system you use.

 

[JPlybon]

It's easy they need to build a better PUMP.