How come I haven't heard about pump failures with
wire tapping boxes as in the past. A couple of years ago
everyone was saying that if you tapped the pump wire
it was 50 / 50 that your pump would die after the first\WOT run.
Now I hardly hear of anyone tapping the wire and getting a
pump failure. Was it just an overreaction with a couple of
failures and then everyone talking about / repeating stories
they heard through the "grapevine" ?

 

You're likely hearing about less because all the focus is on the 3rd gen models. When the 2nd gens (with VP44s) were fairly new, most all of the posts out there were regarding wire tapping. Now that there are fewer posts about wire tap boxes, you hear less about the VP44 failures.

 

Plus, they are rebuilding them better than they used to.

 

I dont think the problem was in taping the pump wire. I think the problem was not having a good lift pump supplying the proper amount of fuel once the wire was tapped. No fuel pressure=pump failure.

Now its common practice to focus on the lift pump issues before tapping the pump! Remember the issue is heat and the fuel is cooling these pumps. More fuel=cooler running pump=less possibility for failure.

 

I'm currently on VP-44 number 3.
I have had a full time fuel pressure gauge monitoring inlet side pressure to the VP Injector Pump since January 2000.


At no time did my WOT pressure get below 10, or my idle pressure get below 7 without my changing the lift pump.
(I have 5 old stock style pumps on the shelf in my garage with the dates, mileage, and displayed pressure when changed)
Now running a Glacier Diesel Walbro pump.

I Installed an Edge Comp in Jan of 2000 without tapping the pump wire.
I hooked up the pump wire using a "Stealth" cover around Sept of 2005 after miles of trouble free driving in EZ mode.
In Dec of 2005, VP-44 number one decided to take the Big Dirt Nap 3 days after Christmas and left me on the side of the road 5 miles from home.

I replaced the pump with a Hot Rod pump and drove it that way until Octoberish of 2007 when I hooked the pump wire back up with the "Stealth" cover again.

Around Mid December of 2007, Pump number 2 Left me stranded in DC at dusk.
Pump builder called to say the fuel solenoid hung open causing the pump to go into hydraulic lock, internally self-destructing in the process.
It wasn't even useful as a core.

Pump number 3 was installed, and the "Stealth" cover will STAY in the tool box drawer.
Still driving in EZ mode with HR pump number 3.

Each time when the pump died, the indicated pressure was OVER 13 psi.

 

well I may regret saying this but I have 160,000 miles on my original vp and the wire has been tapped for a year now and it still pulls strong.

 

I wasn't so lucky. I installed my Edge Comp (not tapped) and took it for a spin to see what kind of power it had. The second time I got on it good...I was on the side of the road waiting for the flatbed to haul me to the shop. Not sure if it was the Comp or just the VP44's time to give it up normally.

Mark

 

They sometimes follow a pattern.

It always seems to be lots of VP going Tango Uniform right after a winter cold snap, when we have a day in the 50s or 60s.
Both of mine followed that pattern too.

 

Everybody says lift pump pressure, it is a good fuel flow that increases vp life. I've been running 20psi+ through 1/2" lines & 90k on my replacement vp.

 

Agreed, I also installed a Scotty Big Line kit on mine before the first Injection Pump died.
Larger lines and fittings from the hard fuel line on the frame rail to the Inlet side of the pump.....also, fuel filter was changed anytime my WOT pressures dropped from "Normal".

 

With all the good injectors available now it is not necessary to tap the wire and abuse it like was needed in the past.More injector less duty cycle

Bob

 

May or may not be true... but pumps are failing, even with good pressure, like Shovelhead implied.
I'm on #3 also. All three went with FASS installed and providing steady 18 psi. Can't pull FP below 16 psi.

I agree with Dr Evil. They are re-building them better than factory originals. Trying to solve problem areas.

RJ

 

i think we hear less and less because more and more people are fixing the problem before it can fail i.e fass raptor and all the other new pumps that have been made to extend the life of the vp44. plus the dont make vp44 trucks anymore so maybe they all got fixed lol good post

 

The more time passes, the less likely a truck is going to have an original injector pump on it. They are rebuilt better, so the older ones are going to be more likely to calve than a newer one. My first one died on the first 5x5 run with the drag comp. My second one never actually died, but it was getting harder to start when hot. I had 5 psi fuel pressure on the first one, and I had a FASS installed with the second pump. I never did run the comp again after the HRVP went in, clutch couldn't take it even on 1x1.

 

Problems with the VP-44 and the original lift pumps are two different issues, which do not really relate to one another, unless you're running below 7-9 psi.

There were three issues with the VP-44:

(1) production quality - the pump has very close tolerances, and early production runs did not have the necessary quality - "fit & finish" was often substandard. Biggest problem was a deflecting rotor which would gall on the inside of the barrel under higher loads, and destroy the pump. A variant was an out-of-round barrel that would eventually catch the rotor and break it.

(2) poorly produced and protected electronics packages - minimal thermal cycling would destroy poorly-made connections and unprotected components in short times, especially in warm months. After 2001, this was the most common problem, by far.

(3) inexperienced rebuilders - again, the pump is complex and demanding to work on. Early on, Bosch did not have good quality controls for rebuilders, many of whom tried to rebuild the pumps using "common techniques" that didn't work well.

Bosch ramped up mechanical production quality between 2001 and 2006, largely because the VP-44 had found its way into fleet trucks for large companies like Fed-Ex - who screamed about the issues. The electronics package was redesigned twice. And Bosch networked fairly well with many rebuilders, designing a fairly good standards and interaction process.

So the pumps that have been replacing the originals have had all three issues "fixed". Bosch did about as much as they could to save a poor design, but they didn't do it for Dodge/Cummins owners, they did it for the fleets - and Daimler/Chrysler's reaction to all of this is a big reason why a fair number of original owners won't buy Cerebrus/Dodge trucks anymore.