Engine/Transmission (1998.5 - 2002) 01 24v with possible pump issues

[Rogan]

Hi guys. I just picked up my 2nd CTD last night. This one is an 01 XCSB 4wd, all stock with 6spd.



I was told it has a failed VP44. Previous owner put in a new lift pump, and added an aftermarket transfer pump. Truck (so far) starts right up and idled well. I drove it out of his driveway, and onto the trailer, where I towed it home with my 12V, and it fired right up, and backed off the trailer fine.



I went up the street with it, just checking it out a little more, and it seemed to stumble a little bit, but no stall. I turned around in the street, and came back to the house and stopped. The idle began to lope like a great big cam would do, for about 5 seconds, then smoothed right out.



There is no CEL illuminated, and I checked that the light does, indeed, self-test when you turn the ignition on.



I was told it would usually not start, or it would start then die, and not restart. .



Any ideas what I should start with, as far as troubleshooting?



THanks, in advance, for your always-helpful information and education!



Regards,

 

[jhoughton]

Blue Chip Diesel has a good VP-44 troubleshooting procedure. Go to their website and take a look at it. Hope it helps, If the LP had failed then the VP-44 is probably the culprit.

 

[Vaughn MacKenzie]

Here-> Blue Chip VP44 Diagnosis

 

[Rogan]

Thanks, houghton and Vaughn.
I read through that last night. It was very informative, and interesting. Straight-shooting, so I liked it.

I did go out last night and check the KOEO (x3) thing, and got a code of P1693 (that was the only code. )

So I think I'll need a scanner to further investigate that, but most likely, it seems I'll be needing a pump

 

[Rogan]

got this:



p-pcu

1693

done



p-ecu

0216

0230

0252

done

 

[Mishkaya]

got this:



p-pcu

1693

done



p-ecu

0216

0230

0252

done

You definitely need a new VP44... #@$%!

 

[Rogan]

oh. . yay. LOL

I did notice this, today. . With the aftermarket pusher-pump off, and the engine on, I held the throttle at about 1600rpm. It held there for about 30-40 seconds, then began to stumble, then started to die out. I maintained my throttle position, and watched as it started to die out. I flipped the switch to turn the aftermarket pusher on. The engine continued to stumble towards stall, then picked back up, returning to 1600. Once it smoothed back out, I let it continue to run there, and turned the switch back off. About 10 seconds later, it started to stumble and drop again. About 1000rpm, I flipped the pusher back on. A couple seconds went by, and it began to pick back up. .

Could it truly be the vp44, or maybe a fuel filter just dirty as hell? If the filter was clogged up heavily, would the ecu still code out, as if it were a failing pump? Or is it not that simple?

Sorry, this is my first vp truck, as my current one is a '96 p-pump.

I assume the vp44 fuel filter is a canister-type, rather than a self-contained one, such as the p-pumped truck?

 

[Sticks]

You need to get a fuel pressure gauge on that thing.

The 0216 can be set by low fuel pressure, not necessarily a bad VP.

The 0230 code is a transfer pump circuit.

The 0252... Not sure. May or may not be a VP death code. Not listed in my list 'O codes.

First things first. Fix the fuel supply issue. Then get the codes cleared and see what happens. Would not be the first time a VP was wrongly condemned by fuel pressure.

 

[Rogan]

You need to get a fuel pressure gauge on that thing.



The 0216 can be set by low fuel pressure, not necessarily a bad VP.



The 0230 code is a transfer pump circuit.



The 0252... Not sure. May or may not be a VP death code. Not listed in my list 'O codes.



First things first. Fix the fuel supply issue. Then get the codes cleared and see what happens. Would not be the first time a VP was wrongly condemned by fuel pressure.

Thanks, sticks.



I have a couple gauges (a gas-car fuel pressure tester), and I think a 1/4npt and an 1/8npt pressure gauges for testing. It can't be as easy as already having what I need to test the FP, and not knowing the vp setup yet, where/how is the best way to go about testing fuel pressure?







edit: I'll search, sorry.

 

[AClayton]

It is the same 1/4 flare connection we use for checking pressures in an A/C unit. The port is on the VP itself in plain view... . it has a shrader valve in it so when you unscrew the plastic or brass cap,you can access fuel pressure there. Simply hook your gauge up and go in the truck and crank the engine momentarily... but not start it... . that should give you 20 seconds in which to test your fuel pressure. I believe 7psi is the bare minimum at idle before it starts to hurt the vp44. You should have well over 12psi.



Alan

 

[Rogan]

It is the same 1/4 flare connection we use for checking pressures in an A/C unit. The port is on the VP itself in plain view... . it has a shrader valve in it so when you unscrew the plastic or brass cap,you can access fuel pressure there. Simply hook your gauge up and go in the truck and crank the engine momentarily... but not start it... . that should give you 20 seconds in which to test your fuel pressure. I believe 7psi is the bare minimum at idle before it starts to hurt the vp44. You should have well over 12psi.



Alan

awesome. I'm headed out of work now, so I'll check this out in about an hour.





(see, why'd you have to bring up AC stuff? LOL I'm so over working on that AC for today! hahaha!! not really, I still need to put all that back together. . )

 

[Rogan]

Here's a video. . I think it's inevitable. . VP. .



VP44 fuel pressure check on Flickr - Photo Sharing!

 

[Sticks]

VP44 supply fuel pressure = 10 PSI minimum. Not 7psi, not "X" cc's per minuet of flow.

Ideally on a stock Cummins, you do not want to see more than 2 or 3 psi drop in pressure from low idle to WOT.

 

[MAllen1]

I had the same problem with my transfer pump. I had no in truck gauge to read from, but would check with a fuel gauge everytime I would change oil and the pump would shoot up to somewhere between 15-18 psi. Then mine would start stumbling to the point where I had to pull over, turn off the truck, wait 5 minutes, then turn back on. Come to find out, I was testing the lift pump wrong. I hooked up the fuel pressure gauge and went to drive it. It started out at 15 psi, not getting any lower than 12, then when the engine got up to operating temp. it dropped to 0 psi. and never got above 5 psi from that point forward. To get to the end of the story, I replaced the lift pump, and no more problems, but to err on the side of caution, I am having an auxilary lift pump from BD installed as well as a set of gauges. Nothing like a $2000 threat to do that to you.

 

[Rogan]

well, mine has a new lift pump, as well as an inline transfer pump, back by the tank.

what's odd is as soon as you bump the starter, and the lift pump pressurizes the system. Once the lift pump shuts off, the pressure instantly begins to fall to ~5psi or less. Start the engine, and it goes to zero, then stays there. I picked up a fuel filter yesterday, so I might put that on tonight. . But I know it's inevitable. . I'm gonna have to drop some big money, in short order.

 

[JCyrbok]

You definitely need a new VP44... #@$%!

Yep, but FYI I drove with those codes and intermintent dead pedal in my 01 for about 1. 5 years before it became to much of an annoyance. So if cash is not right right now, you can get away driving likley for a while before it gets too bad.



J-

 

[Rogan]

Cash is a little tight right now, and I'm dying to drive the truck. . But a potential break-down, and I don't think I can push a 6000lb+ truck off the street! LOL

We'll see. I'm going to tag in tomorrow, so I may loop around the neighborhood a few times, before feeling more cocky than that

 

[MAllen1]

It still could be a transfer pump, they are prone to go out (both types) in stock form. My first one went out in bone stock form. The second one went out after a factory computer upgrade. When that happened, I went with the FASS DDRP, mainly at the time I wanted to keep the lift pump in the stock location. Well the FASS system lasted 50,000 miles (roughly 2 years). I am not trying to single out FASS, they were just the latest casualty. I agree with Sticks, you need a fuel pressure guage in the truck all the time. It's the only way to keep track of it. With what you are telling me about the pressure dropping to zero, it could mean the transfer pump, or pumps. If the one in the tank has gone bad, it could be hendering the one on the side of the engine. My next question is when you checked the pressure, was this all at idle (or better put, did the truck actually go down the road while you were testing)? The reason why I am asking is when these numbers were taken while the truck was sitting still, a transfer pump(s) replacement is in order before you move on to the injector pump. I would check the pickup screen in the tank ( mine has one, don't know if they cross all year models) for good measure. Sitting in the driveway, the pressure should at least be 10-12 psi. At WOT, under stress (going down the road) the pump pressure at bare minimum should be 5-7psi. Any less is unacceptable if you are testing before the injector pump.

 

[Rogan]

From what I understand, there is no pump "in" the tank (at least from what I read in the FSM.

As stated before, the lift pump (on the side of the engine) has been replaced very recently, as well as a 'pusher pump' installed along the framerail, back by the tank.



Looking at the 'new' lift pump, it looks nothing like the OE one. It's more of an inline style pump, which lays horizontal. I've got a pump very similar to it (new) in the garage, but it's quite hard-core, with an average head pressure of ~30-40psi, and can push up to 70-80psi @ 155LPH. But I fear it's too much pressure (?) so I didn't want to try it.



You are correct, in that the pressure tests I've done are all in the driveway, no load. Did you watch the video link I posted? It's quite odd, how the pressure is behaving.



What's the 'maximum' pressure that can be feeding the injector pump? would 30-40 be too much? Or would the overflow valve allow it to cycle back to the tank, rather that barrage the IP with pressure (provided I use the pump in my garage as a tester)?



Pep Boys has a replacement lift pump that very closely resembles the OE style LP, for 158$ (Carter brand). I would rather do a FASS or the likes, but 5-600$ is a lot to find out that it didn't help.



As for the fuel gauge, I'll be getting one very soon; I'll try in the next couple of weeks.



I tested the pusher pump that was added back by the tank, and it pushed 10psi (slow to build, mind you) to the back of the IP, but I just don't think it has the pressure or volume to be able to maintain.



Thoughts?

 

[Sticks]

It's been covered. Get a dash fuel pressure gauge, to see what is going on while you are driving, and seriously consider switching to a FASS, Air Dog, RASP (so they still make those?) or even the Mopar in tank pump in addition to the OEM block mounted pump. If you have a frame mounted inline pump scabbed on to the truck, and it has a independent on/off switch, I question the previous owners knowledge and methods.



***EDITED*** Not going to get into the fuel pressure minimum requirement debate.



For 12 years people have been working on the 24v fuel system issues and the best solutions have been tested, cataloged and marketed. Trying to find a cheaper alternative to the $300 - $600 fuel supply issue will cost you more in the long run. That VP is going to run you $1100 + install if your attempts at a cheaper fix don't work.



The only combination that I have seen work reliably with the OEM block mounted pump is the Mopar in tank upgrade, and it is cheaper than the non pump fuel sending unit.