Vp44 pump possibly going out?? Need help!

[Azrayelle]

Hey guys im having a big issue and iv reached a dead end. I recently had my in tank lift pump go out, I replaced it. After I replaced it it still hesitates at around 2500 rpm, sometimes around 2k but it always hesitates if I let it get to 2500. I did a fuel pressure test with the orilleys pressure tester and I wouldn't show any pressure on the guage. Naturally I replaced the new pump again. It is still doing it and two days ago I was driving down the highway and hit a big bump and it was like the fuel completely cut out for a split second. The fuel filter is new, the pump is new. It starts very easily weather its hot or cold, below 2000 rpm it runs very well. Whats the next step? Please if anyone has any ideas where to test next I would be so grateful.

 

[CanuckRam1313]

Hey guys im having a big issue and iv reached a dead end. I recently had my in tank lift pump go out, I replaced it. After I replaced it it still hesitates at around 2500 rpm, sometimes around 2k but it always hesitates if I let it get to 2500. I did a fuel pressure test with the orilleys pressure tester and I wouldn't show any pressure on the guage. Naturally I replaced the new pump again. It is still doing it and two days ago I was driving down the highway and hit a big bump and it was like the fuel completely cut out for a split second. The fuel filter is new, the pump is new. It starts very easily weather its hot or cold, below 2000 rpm it runs very well. Whats the next step? Please if anyone has any ideas where to test next I would be so grateful.

Have you also looked at the injectors?

Key Diagnostic Procedures

• Injector Balance/Contribution Test (Scan Tool):A scan tool or software like EFI Live can log balance rates (BALRCYLx). A high positive number (+3 or 4) indicates the ECM is adding fuel to compensate for a weak cylinder, while a high negative number (-3 or 4) indicates it is reducing fuel for a cylinder that is running too rich.
• Injector Kill Test (Snap-On/Xtool): Selectively disabling an injector allows you to check for changes in engine idle. A malfunctioning injector will produce no change in sound or vibration when disabled.
• Resistance Test (Multimeter):Check injector solenoid resistance. 5.9L Cummins injectors should generally fall within two Ohms.
• Physical Symptoms: A "dead" or severely out-of-spec injector (commonly observed on high-mileage units) may cause white/blue smoke at cold idle, a rough idle, or a "stutter".
• Injector Quantity Adjustment (IQA): When replacing, ensure IQA codes are programmed using a scan tool for proper flow rates.

 

[CanuckRam1313]

What's the current mileage?

When was the last time the top end was looked at?

5.9L Cummins valve adjustment (valve lash) is a straightforward, routine maintenance task, typically recommended every 100,000 miles. Using basic tools like a 5mm Allen wrench, 14mm socket, and feeler gauges, you can adjust the clearance between the rocker arms and valves to spec (usually $\sim$0.010" intake, $\sim$0.026" exhaust) at TDC for optimal performance.

Key Steps for 5.9L Cummins Valve Adjustment:

• Tools Needed: 14mm wrench, 5mm Allen socket, feeler gauge (0.010 and 0.026 recommended), engine barring tool.
• Preparation: Remove the valve covers and locate the TDC (Top Dead Center) mark for cylinder 1.
• Procedure (Two-Position Method):
  • Position 1 (TDC Cylinder 1): Adjust intake valves 1, 2, 4 and exhaust valves 1, 3, 5.
  • Position 2 (Rotate engine 360°): Adjust intake valves 3, 5, 6 and exhaust valves 2, 4, 6.
• Adjustment: Loosen the 14mm lock nut, turn the 5mm adjuster until the feeler gauge has a slight drag, and tighten the lock nut to 18 ft-lbs while holding the adjuster steady.
• Specifications: Intake lash is typically 0.006–0.015 inches (0.15–0.38 mm), and exhaust is 0.015–0.034 inches (0.38–0.86 mm), with roughly 0.010" and 0.026" being common targets.

Note: Always verify specific clearances for your year (12-valve vs. 24-valve common rail).

 

[Azrayelle]

The current mileage is 460k miles. I have never done a valve adjustment before. I didnt know that I needed to. Also I have never checked the injectors to answer the previous question.

 

[CanuckRam1313]

The current mileage is 460k miles. I have never done a valve adjustment before. I didnt know that I needed to. Also I have never checked the injectors to answer the previous question.

I'd recommend that you look at doing both.

 

[Azrayelle]

I'd recommend that you look at doing both.

Noted. Do you think one of those things could cause the hesitation im having?

 

[CanuckRam1313]

Noted. Do you think one of those things could cause the hesitation im having?

With almost a half million miles on that Cummins and no history of a top-set done or the injectors tested and calibrated, I'd say it's a good time to check both.

If you're not versed in doing the appropriate pump and injector testing and calibrations, I'd find a Cummins authorized diesel shop to do it for you.

You'll also want the top end looked at and set at the same time so that everything is fresh and calibrated properly.
Your Cummins will thank you!

I'd also toss in a good dose of something like Stanadyne Performance Fuel Additive with a fresh tank of good diesel as well.

 

[06 Dodge]

I would also have someone check the the fuel control actuator (FCA) at this URL it gives you an idea what it does: https://dieselpowerproducts.com/blo...ce-a-fuel-control-actuator-fca-on-your-diesel

 

[NETim]

If I remember right, the ‘02 VP44’s had a problem with some internal sleeves wearing out prematurely because they were made of bronze. But when that happened, they would throw a code. 0441, I think? May not be your problem. I’m sure the issue would have arisen before now anyway.

Anyway, when the lift pump craps out on these VP44 trucks, there goes the VP as the majority of cooling on those pumps comes from the fuel. A lot of guys would install a good lift pump in place of the factory lift pumps. I had a Bulldog on mine if I remember right. Lots of pressure and plenty of fuel flow.

Besiides what’s already been suggested, the VP may well be on the way out.

Replacing the VP isn’t a bad job. I did it myself in the driveway waaayy back when I still had my ‘02 3500. That’s how I earned my YouTube master mechanic degree.

Good luck with the old girl.