Archived 2001 all but dead

[Karish]

Truck: 2001 2500 4x4, 143k Miles. Changed a fuel filter a week ago (cleared up a bit of hard starting it was having), filled with fuel last week, has been operating very well.



Driving 10-15 mph (driving back to the firing line after setting up a 600 yard target) the truck goes from running just fine to sputter, sputter, stop. Got it restarted after nearly shaking itself apart. It will idle just fine, but darn near nothing else. Get the RPMs above 950 or so and it just sputters as though it was starving for fuel. Okay, get the truck out of the impact area (a good thing) manage to idle the truck to place that will be out of the way.



I changed the fuel filter..... no change.



Have a fuel pressure gauge at the inlet to the infamous VP44; it is at 16-18 psi when it's running. Doesn't appear to drop when it's sputtering at 1,000 RPMs. . but that could be an instrumentation limitation.



Read other thread about cracking the injectors at the head and cranking the engine to allow fuel through. I've not done that. . yet. Never done anything on the high pressure side.



I've got 4 hours before I'm going in for some minor foot surgery that will not make working on the truck any easier. Any suggestions are appreciated.

 

[JKreiss]

Check engine light? Any codes? It sounds to me like you've got more going on then some air in the lines. I would think it would have cleared out by now. I would definitely check for codes first.

 

[Karish]

Yes, I forgot to include previously. P1693 is the only code. Supposed to mean: DTC detected in ECM or PCM. Not sure what a DTC is. ECM = Engine Control Module, PCM = Power (?) control module.

 

[JKreiss]

The 1693 is a companion code, usually paired with another code. DTC just means diagnostic trouble code. You could crack the fuel lines if you want and try to bleed them, there's a lot of good info about that here, but i think that's just wishful thinking. My gut says VP-44 but honestly i can't really help you. Hopefully somebody will be able to give you some better insight. You could double check all your fuel lines and especially the fuel filter cap. Make sure you have no signs of obvious leakage where air could be getting into the system.

 

[Karish]

Thanks. I did check for fuel leaks all along the system and found no evidence of leaks. Unfortunately, I too have a bad feeling about the VP44, perhaps based on nothing more than the horror stories one hears about it. Thinking I'll idle the beast over the Base auto hobby shop, at least it'll be close to help. Looks like I'll be accepting the offer of a loaner vehicle from someone in the Squadron for a couple of days.

 

[Sticks]

It sounds like it is just air locked. Try cracking loose (1- 1 1/2 turns) the # 1, 3, 4, and 5 injector lines at the head and crank on it for 15 seconds, tighten them up and try it again.

 

[Karish]

Sticks,



I'll try that today. Should I place absorbants around the area when cranking to prevent a bunch of fuel from being sprayed all over the place? Don't want to report: good news is the truck started working, the bad news is it burned to the ground.

 

[Batphreak]

Little bit of fuel that gets sprayed out from cracking injector lines really shouldn't hurt anything. Diesel fuel isn't nearly as volatile as gasoline, plus these compression ignition engines don't have high energy spark mechanisms that could throw the juice to light fireballs. Just avoid putting your skin in the spray, the pressure is high enough that it really really hurts.

 

[Karish]

Latest update:



I craked the number 1,3,and 4 injector nuts... only ones I could get my wrench on. Series of things to report:



1)at first the pressure at the injector pump (IP) inlet was low... 0 to 10

2) Cranking the engine resulted in no fuel at the injectors... . indicating no fuel into the IP.

3) Drained a bit of fuel out of the filter housing... good there is fuel there.

4) Fuel pressure did go up after a few cycles of running the lift pump (LP).

5) Got fuel at the injectors. . retitened them

6) Pressure at the IP inlet went up to 18 psi when the LP was running.

7) Crank truck... it starts to hit... sounds like its running on only a few cylinders. . fuel inlet pressure goes up, and it sounds better, not good like its missing or lobbing a bit. Cannot give it any pedal it just sputters

8) while trying to give it some pedal when it is idling the IP inlet pressure drops slightly. . 1 or 2 psi. Could indicate poor fuel supply, but I would think it would drop more than that if it were really starving for fuel

9) the IP inlet pressure does not stay up after the LP turns off... is that normal? does the fuel drain out via the return line?



Right now I don't know which direction to go: look at possible blockages in the fuel supply, or it's the IP that's rolled over and died.



Any more words of wisdom?

 

[HHhuntitall]

I don't know how much wisdom is in it, but there's experience. If you've got any kind of pressure at the injection pump when it's cranking or running, it should run at idle, given the pump is good. If it's got 5-7psi at full throttle, it should run fine. It sounds to me like either the TPS/APPS (Throttle Position Sensor/Applied Pedal Pressure Sensor) is bad or the injection pump is toast. Strange that it idles but when you touch the throttle it sputters, suggesting the TPS, IMO. Geno's Garage sells the unit cheaper than anywhere else, if you decide to try that route. Dodge want over $300 for these... .

AFTERMARKET APPS THROTTLE POSITION SENSOR ('98. 5-'02)-Dodge Cummins Diesel Truck Accessories – Geno’s Garage



Does it ever clean up at idle, or does it keep missing?



I'd recommend a little reading here: Blue Chip Diesel Performance Specialists and maybe a phone call. Good luck.

 

[Karish]

HHhuntitall,



It sounded better at idle yesterday, it did not really idle nicely today. I was thinking about the possibility of the throttle position sensor being dead. Might explain why it goes to *(&# when the pedal is applied. This happened so quickly, it had the hallmark of being an electrical issue. Guess I'll have to figure out how to check that. Thanks for the links.

 

[Sticks]

Rinse and repeat. These engines will idle... well run (rather poorly) on one cylinder.

I've done filter changes and VP replacements that had one or two lines that stayed air locked until I cracked the line at the head.

Try this, once you get it idleing again, try cracking the injector lines again while it is running. Keep a thick rag and place it over the injector nut once you have the wrench on it. You may or may not hear the cylinder drop out. Leave it loose for a few seconds, then tighten it back up and move to the next one. The rag is solely to keep you from taking a spritzing of fuel while you are doing this.

The LP pressure dropping is a concern. Try to get the engine to idle normal first, then we can move on to the next problem.

It is possible that you have a bad tank of fuel and may have loaded the filter up, or your sock in the tank is plugged. If you have access to an air compressor, try back blowing the fuel supply line on the tank side of the LP (remove your fuel filler cap!). Either at the banjo bolt, or the quick connect lines below it on the frame rail.

 

[Karish]

Thanks, I'll try it again. Once I get out there, I'll try limping ito the base auto skill center to get a code reader on it to see if there is more to learn from that too.

 

[Karish]

Some more developments. I limped it to the base auto skills center where they read the codes (for $25!):

P1688: Manufacturer controlled computer circuit

P0251: Fuel injection pump mechanical failure fuel valve feedback circuit

P0252: Injector pump A rotor / camshaft sensor malfunction.



They did look at a web page for a minute or two (shopkey5.com). All three code list a failed IP as a possible cause. 251 lists some other things including low battery voltage, which isn't an issue. Could also be an electical communiations problem between the fuel pump control module and the engine contol module. Unfortunately the tests for that require the dedicated use of a code reader, which I do not have... yet.



I did crack the injector fittings on those I could get to while the engine was idling. Definately can tell when it looses fuel out of the fitting by how it runs. But, it operates the same as before after the fittings are retitened.



Did perform a couple of tests proposed in "How to diagnose the VP44 fuel system" by Blue Chip Diesel. First, interchanging the relay for the fuel pump and horn: no difference. . not surprised. Next one was to disconnect power to the lift pump before cranking. It seemed to start/get to normal idle slightly better without the LP powered up. They say that's an indication of cracked or broken diaphram inside the IP. . which means it needs to be replaced.



Most of diagnostics presented by Blue Chip are for an engine that does not start. Mine will, run very rough then smooth out. As I understand it, if the IP weren't making high pressure, the injectors would not pop open and spray fuel into the cylinders. So it appears to do that under one set of conditions: idle after a rough start. Need to research this camshaft position sensor to make sure that's not the culprit before I spend a bunch of money and an IP and try to find someone who knows how to install it properly.



Thanks for the help so far. .

 

[Sticks]

Electrical issues. Check the harnesses around your fuel filter (when the problem started) and swap out the Injection Pump relays in the PDC.

 

[HHhuntitall]

I'm gonna say it's the injection pump. The computer on the top of the IP is a piece of cr*p, well, the whole IP system is, too, but it's what you got to work with, so... ... it's already throwing a siezed rotor code, as well as a computer failure code, so I'm betting it's the IP. If it's been hard to start, and changing the filter fixed it, I'm gonna say the IP has not been getting enough fuel, and that's about the worst thing that can happen to them. I'd look at the TPS and follow these calibration directions to test it and see if it has proper voltage: Blank



If the TPS is good, I'm afraid it's bad news..... remember, the injectors open 300-600psi, while "high" pressure for these pumps is up around 10,000 psi. The pump may still be making enough pressure to open the injectors, or some of them, and make it idle, but anything above that, and it quits.....



One question, though, does it idle itself up when you let out on the clutch and lug it some? Or does it just pull down?

 

[Karish]

Once it starts, rattles and shakes, then idles okay, it will take being put into gear and will move at idle, but will not take any more throttle than that. I can hit the blazing speed of 8 MPH when conditons are right... slightly down hill, no pot holes, etc.

 

[HHhuntitall]

What I was asking, though, was does it give itself fuel? At take off, the trucks will fuel themselves to prevent loss of rpms, even if you don't touch the throttle. It's handy when working off-road, at times.....

 

[Karish]

If I understand your question correctly, the answer is the truck does not lug down when put into gear (automatic trans). It will pull itself away from a stop and idle along at about 8 mph (flat and level) and will pull itself up slight inclines, but does not have enough power to get over bumps even and inch or so from a stop. So, something is telling it to get enough fuel to do that.



I've called Blue Chip, but have not been able to speak to anyone yet.

 

[HHhuntitall]

Ah, it's an auto. On standards, when you let out on the clutch, it will automatically idle the engine up to keep it from lugging. But your auto won't let it do that. I'm still thinking it's the injection pump. The P1688 code you have indicates an internal pump failure. The most common failure I've seen on these pumps is the computer on top of the pump followed by the high pressure rotor in the head, and then the high pressure cylinder; most of what you can read on Blue Chip Diesels website is right in line with my experiences. The loss of communication, and the rotor siezure code, tell me it's gone. Did they clear and reset the codes at the skills center? Sometimes, that will let it start and run for a little while, then it will die or when it's shut off, it will not restart.



Let me add that I don't have near the experience as Chip does. I've only pulled apart a handful of these pumps, ordered the parts, and rebuilt them. But there have been several I couldn't fix, as the computer was toast. I learned that the hard way on some of my own stuff. It cost me in parts, but I think it was worth it for the education. Without a proper test bench, there is no way to test these pumps. About the cam shaft sensor: if it was bad, the truck would come up in rpms, but without any power. Loss of communication with the cam sensor makes the truck go into "limp" mode and it only makes @1500? rpm... . which is enough to get it off/down the road to a safe location, or loaded on a trailer. It will idle fine. The dying when touching the throttle is definitely a lack of fuel issue. It is probably starting and idling roughly until it speeds up enough to build all the pressure it can to open the injectors. That's all it can do. When you touch the throttle, it tries to pressure up and it can't do it, losing timing and internal pressure through the galled and damaged rotor, losing pressure to the injectors, making the engine die or miss. It just happens it can still make enough pressure to idle at the moment.