VP-44 Dying?

[HiPerf360]

My truck has a weird stumble and almost dies when I let out of the throttle after accelerating with the Blue Chip box on. The truck also seems to have a miss while driving on the highway with the box on or off, it also has a rougher idle than it did before. When I accelerate at WOT the truck runs as good as ever even with the box turned all of the way up. Any help would be appreciated.

 

[Whitmore]

Johnathon,do you know what your fuel pressure is durring all this, your sig does not show you have a gage? your situation is kind of different but I would always look at the fuel psi first,if its ok than go to the next step. IMO... ... ... ... ... ... ... Kevin

 

[Ramafid]

I have the same type of situation. Truck runs great at WOT but just cruising around at light throttle is not a lot of fun. The stumble is very annoying. I noticed more smoke at start-up. How about you? My fuel pressure is great so I know that's not an issue. HIPERF360 does the blue chip box only add fuel or does it do timing and fuel. I'm trying to see if advancing the timing has anything to do with this problem. I put 45 cetane fuel in the tank and the stumble doesn't seem as bad ( maybe just coincidence). I'm beginning to think it's the injection pump or the ECM. Seems like we have lots of company with this problem.

 

[HiPerf360]

Whitmore- I know I have a fuel pressure problem at WOT but just driving around it has at least 3psi. that is when the low fuel pressure light comes on. But when it stumbles on the highway it at least has positive pressure at the inlet. The fuel system was going to be the next upgrade so I might be doing that sooner than I thought.



Ramafid- The Blue chip box that I have does not adjust timing but I do have an EZ for that.

 

[WCrovo]

I low fuel press light

Do we have a low fuel pressure light? You guys have me parinoid about the fuel pumps in my CTD.

 

[Todd T]

the injectors are more than likely the reason it idles a little rough. (Sorry DD)



the stumble could be a few things. first thing to check out is the ground to your boxes, connections inside the fuse holders and the MAP harness. iether of these with a bad connection will cause a stumble every now and then.



if the truck lunges forward or feels like you turned the key off and back on real quik. check the MAP harness for sure. if one side or the other of the sensor looses its signal the truck will either run-away or die momentarily.



use dielectric grease on all connections too.



if the truck surges or bucks while driving under light throttle, hold on. we havent figured that one out yet. but i CAN tell you its not fuel pressure or the VP44 going bad.

 

[Bad340fish]

His truck just recently started doing this though. I have ridden in the truck countless times and if anything the DD2s smoothed the idle out over stock. I think it only surges at idle after you romp on it hard. I believe all the problems he mentioned in his post started in the last week or so. The truck has had the blue chip and ez on it for a long time. . and the injectors for around 4 or 5 months i think.

 

[juicedcummins]

If your blue-box is scotchlocked to the injection pump good place to check. I have had trouble with that after going in for work.

 

[HiPerf360]

Todd T-

What Clark said is true, the injectors actually made it idle smoother. The part that is weird is the truck almost dies when you let off the throttle after its been on the floor for a few seconds and the it over compensates to about 1500rpm then idles real rough (Like a big cam in a gas engine).

I am going to check all of the connections tomorrow but I think all of them are fine, when I installed all of them I used dieletric grease on all of the connections and shrink wrapped everything but the pump wire.



Thanks for the help

Jonathon

 

[Whitmore]

Just want to let all know that the advice to get fuel pressure gage has saved me a big headace , my lift pump decided to take a vacation at 23k but the good news is my gage told me so and I did not further damage my VP-44, my lift pump is so weak that it can only hold 3 psi at 65 mph on flat ground, and the slightest hill will take it to 0 psi , I babied it home and called the stealer to see if I could swap the pump out ,he said to drive it up here so we could take a look and I said forget it I will fix it at home, I am researching the best system to replace the lift and will go for it , they can stick their warrenty ,why would I let them put a new OEM proven crap lift pump in my rig anyhow... ... ... ... ... ... ... ... ... ... Venting with pride ... ... ..... Kevin



Oem lift pumps are crap



If you dont have a f/p gage get one

 

[Cobra]

fuel pressure gauge

exactly what Whitmore said. I put gauges on my truck and my fuel pressure was at 15 psi at idle. One monthe later it indicated 3 psi at idle. Took the truck to dealer they put manchanical gauge on truck, 3 psi. Changed lift pump. 20 psi now. life is good.

 

[Stefan Kondolay]

I think mine died yesterday. I will post my findings.

 

[HVAC]

Whitmore...Your Beautiful Man!

Well Done



I have witnessed the death of several VP44's that were the result of bad lift pumps. I sure appreciate seeing guys getting a leg up on this problem.



Consider an aftermarket pump and relocate it back near the tank, it's a beautiful thing It's not that hard to do either. Just be proactive and address the problem.

 

[HVAC]

Typical Problem

HiPerf360



I've experienced the problem you have described only too many times. With my rig it is more severe though. If I let off real hard (like to avoid running an intersection) it will kill the motor. It doesn't want to restart either. Kinda like all the fuel has been drained from the injection system.



Mark Chapple has noted this phenomenon too. He mentioned this behavior has wrecked a few pumps no less. He told me that when he dynos a truck he purposely backs out of the throttle a step at a time to avoid this drying out of the injection system. His point was that chopping the fuel after a hard run can effect the ability of the pump to adequately cool itself for a moment or two.

 

[HiPerf360]

Well, I think the problem might be fixed... changed the fuel filter and redid all of the connections. But I still need a new fuel system. Oh well it's just money isn't it?... LOL...