I am new to diesels, this being my first one, so bare with me.

I have a 2001 Dodge 2500 4X4, short bed extended cab with a 5.9 Cummings and automatic transmission. The truck is bone stock with the exception of an Air Dog 100 lift pump and filtration system. I also have a Super Chips Flash Pac tuner for the truck. I bought the truck last May with a tick under 100K miles on it. It currently has approximately 110K on it.
The truck checked out fine before I purchased it. It ran and pulled fine. In June the truck started giving me trouble. It just wouldn’t pull a small load with out stumbling and struggling. So I got some advice from local diesel mechanics, did some checking and ran some test and determined the stock lift pump and VP44 had failed. I jumped on the internet and found a VP44 and the Air Dog for sale on line and purchased them. Once the parts arrived I went to work and installed these parts. The truck has performed flawlessly since. It has run as hard as I wanted it and pulled anything I wanted it to at most any speed I wanted it to. Then about 3 weeks ago the truck seemed to run a little different. I noticed the truck missed, stalled, stumbled or skipped. I know diesels don’t skip. That is just the best description I can come up with.

I was driving through town running approximately 50 mph. The truck was at running temperature, going up hill, no load and approximately 3/8 of a tank of fuel when the truck “skipped”. It only did it once. Just a little hic-up. So I didn’t think much of it. Then about 10 minutes later it did it again. Soon afterwards I was at work with the truck in the parking lot. The next morning, the same situation, 50 mph up hill at running temp and the truck skips. I assume I have gotten some bad fuel and immediately replaced the fuel filter and drained the water separator when I got home. Later that afternoon I experienced the same issue. Again, up hill, 50 mph ¼ tank of fuel, and the truck skips. When I got off work the next morning I stopped and got a bottle of Lucus fuel treatment poured that in the tank and filled up with fuel. Several days later the truck has not missed a bit. So I think I have this fixed and all is good. Then it happened again. And believe it or not, the same scenario, up hill, 50 mph, less than ½ tank of fuel, at running temperature. The truck will pick up and run if you get in the throttle when it skips. When I filled up this time I used a bottle of Seafoam fuel treatment because I already had it. That was Friday, April 16. Today is Monday April 19 and I have had no problems. But I still have over ¾ tank of fuel.

What have I done?
•Checked for engine DTCs with the Super Chip and a Dodge scan tool. No codes are set.
•Placed the factory tune back in the truck and removed the Super Chips.
•Replaced the fuel filter, twice.
•Drained the water separator 4 times. Always looks like pure diesel to me.
•Checked the fuel pressure at the VP55. It is 16 psi +/- 1 psi.
•Checked the volume of flow. This was approximately 1 gallon in 25 seconds
•Checked for kinks in the fuel lines. None found
•Checked for leaks in the fuel lines. I don’t see any.
•Checked the voltage out of the TPS (APPS). .39 volts at idle and 3.50 volts at wide open throttle with a very smooth increase and decrease in voltage depending the direction of movement.
•Opened each of the fuel lines at the head and checked for fuel. All lines have fuel at the head.
•I called the dealer I got the pump from today for advice. They want me to return the VP44 for evaluation. The guy I talked to said he wanted to be sure the VP44 wasn’t the problem. I guess the VP44 could have a problem. But with it not setting codes I am not sure.

I think that is all I have done.

I don’t know what else to check. As I said earlier, I am new to diesel engines. So I have no clue which way to go from here. Is there something else I can check before I remove the VP 44 and send it back? Anyone got any suggestions? Guidance? Words of wisdom? Prayers?

Any help would be appreciated.
Thanks in advance,
KwS

 

it might be the ip or a bad injector

 

id pull the vp and send it to him to check under warranty.

 

no codes puzzles me, one would think a code would be set here

since no codes this leads me towards a fueling issue, you have excellent delivery with the airdog and you have changed filters so I am thinking IP myself

before you jerk it out can you tell me what the RPM gage does when this hesitation happens......reason I ask id I have seen a bad wiring connection cause the MPH to spike maxwd out and it would cause the motor to go into limp mode for a second and it would actually stumble...................and this would set no codes either

 

I have tried to look at the tachometer when it does this. But it is normally so quick I can't catch a change. If anything the the tach may drop 100 or so RPMs. What sort of bad wiring connection should I look for? On the engine or some other place?

One thing that seems to be a general concensus is the VP44. Everyone thinks that could be an issue. So depending on your answer to the above question, I guess I will be shipping it out in a few days.

KwS

 

On my 98 I had the same problem. except my tach would zero and then come back. Kept getting worse and worse. I got lucky and it ended up being the crankshaft sensor but I think the 01's have a camshaft sensor instead.

 

how hard is the cam sensor to replace? I've been experiencing pretty much the same thing with no codes. I'll be at whatever percentage throttle and it will ocassionaly cut out , "fall on it's face" whatever you wanna call it and come right back. Sometimes makin it kinda jerky. I've got a new APPS, good fuel pressure, and no codes, so I'm like you. I'm at a loss as to what it is.

 

I'm not sure on the 01s but I'm betting its not hard. I got my sensor from carquest and it took all of 20 minutes to change out and I had to pull the starter to do it.

 

I just did my cam sensor last weekend. It isn't too hard but an extra set of hands helps. It is under the vp44. Its a little hard to see it but you can follow the wire down and figure out where it is.

 

What were the symptoms on your truck that led you to determine your's needed replaced?