Howdy All,

I have a 2wd 01 2500 5.9 with very few modifications.  Primarily an Airdog Raptor FRRP  a K&N filter and a 5" turbo back exhaust.  I normally run 1oz/gal of Walmart 2 stoke oil in my fuel and my truck as been an absolute workhorse and has run super smooth....until this morning.

I filled up with fuel yesterday and ran about 65 miles.   This morning, I headed out to the hunting property.  As I got onto the highway and accelerated, my truck started "stutering" (for lack of a beter term) as the RPM climbed.  I pulled off of the highway, and put the truck in neutral.  With the truck in neutral, I slowly reved the motor up to 4500 RPM and it went up nice and smooth.  I put the truck back in gear and took it over to my local O'reilys just to be where I could get stuff if necessary.  I first checked my transmission fluid thinking that it might be that.  It was a little bit low but not much.  I added 300ml just to be on the safe side and headed back home.  Shifts were still erratic and the truck was still stuttering.

I spoke with a good friend over the phone and he mentioned that it could be a fuel issue.  I pulled the fuel filter to give it a quick look and didn't find anything glaring or big in the filter or in the fuel drained from the bowl.

I went in to read a few articles on what it might be and someone mentioned that, even if you just changed the filter recently, try putting a new one in.  I decided to give this a try and hopped in to go up to my local NAPA around the corner from the house.  BRAIN FART!!!  I forgot to reprime the bowl and fuel system before driving.  Needless to say, I ran my VP and cylinders dry....ARRRRGH!!!!!

I pushed the truck back home, broke loose 1,3 & 4 and commenced to restarting the truck.  It took a bit longer than norma but finally caught and ran rough, as it has in the past when repriming.   I tightened up my injectors but it never smoothed out.    I cracked 1&3 loose again and let it run rough of a few minutes to push air out.  Re-tighten again and nothing.   I bumped my starter and bled off the pressure test port on the VP44 to ensure that air wasn't trapped there.   Restart and I have a smoother idol but ZERO Pedal....Dead.....Deceased......PUSHING UP THE PROVERBIAL DAISIES!!

I attempted a ECM reset for pedal top/bottom but it makes not difference.

I finally decided to stop doing anything further with it until I had a chance to hear from folks who know a lot more than me.

Current state is that it will idol smooth at 800rpm but pedal might get it to 9-1100rpm max and it turns rough rough rough.

PLEASE GIVE ANY ADVICE YOU CAN.  I got laid off from the oilfield last month and really need to have a running vehicle to have any chance at finding work again.

Any and all help is highly appreciated.

Thanks,

Doc 

That's normal. There is only one report of anyone setting a...

http://articles.mopar1973man.com/2nd-generation-24v-dodge-cummins/59-obdii-error-codes-cummins/155-p0168-decreased-engine-performance-due-to-high-injection-pump-fuel-temperature

So I tend to toss the overheating thought out the window. But now AC noise will create heat with the chips and electronics of the PSG causing the same kind of failure. As you pulse a sine wave positive to negative on a 14 volt DC it will create heat on transistors and MOSFETs and create the failure.

P0251, P0252 and P0253 is all electronics failures of the MOSFET that controls the fuel pin solenoid.

P1688 is a failure of the PSG and not handshaking with the ECM when the key is turned on.

All these are power related issues.

Not necessarily disagreeing with the fact the VP44 has failed more than likely via temperature. The real question is how. The electronics package on the VP uses the VP44 body as a heat sink to draw out heat. As the overflow opens the heat saturated fuel heads for the tank. For us running a 150, our pumps will cycle the entire tank of fuel (if full) in just under 13 mins which may or may not be enough time to remove enough heat.

Electronic solder connections can use various forms of low temperature solder that melt from 190 degrees F to the 300's depending on what solder type used 160 degrees may not be an issue but it's not a help if soft solder is used.

If I have the opportunity I will pay recondoc a visit and go through a very in depth diagnostics and if he needs it a hand replacing that VP44.

Edited August 31, 20159 yr by Vais01

As long as the overflow valve is open and fuel pressure is above 14 PSI then your returning to the tank. Then if you keep better than 1/2 tank of fuel then the fuel temperature is typically lower. But temperature related failures tend to alway be pointed at the fuel supply issue which isn't always true. Like most people are shocked to find out a typical summer high temperature is Riggins, ID is 110-115*F like this summer it hit 117*F for one day. So We have the super hot summers here. My injection pump has 201k miles and 9 years old and not had a single problem with extreme heat. I've measure the fuel temp in the tank as high as 140-150*F easy.

 

As for electronic they will withstand huge amounts of heat non-operating. Liked I've left my laptop in the truck on a summer day turned off and it will survive cab temperature no problem. Remove it from the truck and turn it on and allow the fan to cool it down before work with it no problem. Same kind of circuit boards ans solder. Heck the CPU temp of a normal PC can reach well in the 160-180*F under full load. Got to remember the heat soak of the engine can be as high as 190-200*F so I'm sure that used a solder well above the worse heat soak temps.

 

This why I go back to power supply more so. Because if it was temperature related issue we would hear a ton of people losing VP44 in the southern states like Texas and such. Still even in desert states no one is reporting a P0168 codes.

 

From the Cummins Books...

This fault code is typically set when the VP44 fuel pump controller communicates to the engine ECM that the fuel temperature
measured in the fuel inlet to the pump (VP44 temperature sensor) exceeds the allowable threshold value (93°C [199°F]).

 

Just a thought.....

 

If you do go down the road to a new VP44, maybe look at installing a fuel pressure gauge.  That will help you catch any future problems and offer some insurance to your new IP. 

As long as the overflow valve is open and fuel pressure is above 14 PSI then your returning to the tank. Then if you keep better than 1/2 tank of fuel then the fuel temperature is typically lower. But temperature related failures tend to alway be pointed at the fuel supply issue which isn't always true. Like most people are shocked to find out a typical summer high temperature is Riggins, ID is 110-115*F like this summer it hit 117*F for one day. So We have the super hot summers here. My injection pump has 201k miles and 9 years old and not had a single problem with extreme heat. I've measure the fuel temp in the tank as high as 140-150*F easy.

 

As for electronic they will withstand huge amounts of heat non-operating. Liked I've left my laptop in the truck on a summer day turned off and it will survive cab temperature no problem. Remove it from the truck and turn it on and allow the fan to cool it down before work with it no problem. Same kind of circuit boards ans solder. Heck the CPU temp of a normal PC can reach well in the 160-180*F under full load. Got to remember the heat soak of the engine can be as high as 190-200*F so I'm sure that used a solder well above the worse heat soak temps.

 

This why I go back to power supply more so. Because if it was temperature related issue we would hear a ton of people losing VP44 in the southern states like Texas and such. Still even in desert states no one is reporting a P0168 codes.

 

From the Cummins Books...

 

I am very borderline to that temp at all times even with the 150 pushing at 17 PSI. Today after making a good drive to a shop and a few offices I had a fuel temp of 185 and a spike of 189 degrees F this is with roughly 26 gallons of diesel in the tank. I am considering finding a small fin and plate cooler to route the fuel through to try and drop the temps 20 degrees. 

Edited August 31, 20159 yr by Vais01

Just a thought.....

 

If you do go down the road to a new VP44, maybe look at installing a fuel pressure gauge.  That will help you catch any future problems and offer some insurance to your new IP. 

 

you at least need this to help look after a new VP, even an old for that matter. 

Cooler will do absolutely nothing

 

As you see there is a air space between the circuit board and the cover and the cover is plastic then the out cover is aluminium. So external coolers don't work at all being you attempt to cool the plastic body and not the circuit that is heated to the temp of the fuel. There is also the possibility the sensor in the pump is bad or off. Like I said there is only be one report of a over heat. I would check with a IR gun. 

 

There is more heat in the aluminium body that that plastic cover will do anything about... I still say the PSG is damaged from electrical noise that heat. Which is very possibly how the fuel temp sensor is off because of electrical damage.

Cooler will do absolutely nothing

As you see there is a air space between the circuit board and the cover and the cover is plastic then the out cover is aluminium. So external coolers don't work at all being you attempt to cool the plastic body and not the circuit that is heated to the temp of the fuel. There is also the possibility the sensor in the pump is bad or off. Like I said there is only be one report of a over heat. I would check with a IR gun.

There is more heat in the aluminium body that that plastic cover will do anything about... I still say the PSG is damaged from electrical noise that heat. Which is very possibly how the fuel temp sensor is off because of electrical damage.

I will agree the temp sensor may be a little off but I do not believe it is that much. A stacked plate cooler can drop the temps a full 10 degrees but unfortunately I have yet to find one of appropriate size to accommodate 2.5 GPM and reduce the fluid velocity down to 1 FPS to adequately cool the fuel.

I do plan on changing fuel lines so it's possible the new pressure side line will help reduce the temps. I will keep everyone up to speed on that in my own thread in the future.

I can tell you Duramax uses a cooler for fuel supply too and I can tell you the location under the truck is poor. The cooler ends up packed with mud and debris so the cooler is worthless. Also make sure to have a thermostat too because the fuel temp gets too cool it will cause the truck to start up backwards. I've seen several reports of home made coolers on VP44's doing this and having 5 or 6 reverse gear and only 1 forward gear. Fuel temperature also affects timing so excessively cold will over advance the timing so warmer fuel tend to retard. Again this why I don't suggest the coolers and not worried about it. If it does run backwards the engine will be ruined in a short time being there is no oil pressure.

I can tell you Duramax uses a cooler for fuel supply too and I can tell you the location under the truck is poor. The cooler ends up packed with mud and debris so the cooler is worthless. Also make sure to have a thermostat too because the fuel temp gets too cool it will cause the truck to start up backwards. I've seen several reports of home made coolers on VP44's doing this and having 5 or 6 reverse gear and only 1 forward gear. Fuel temperature also affects timing so excessively cold will over advance the timing so warmer fuel tend to retard. Again this why I don't suggest the coolers and not worried about it. If it does run backwards the engine will be ruined in a short time being there is no oil pressure.

I agree that location is critical. I wouldn't place it under the truck but somewhere on the firewall would work well enough to keep the temps down and not over cool the fuel. Ford 6.7 powerstroke also uses a frame mounted fuel cooler. I am not certain the 4th generation Ram trucks do or do not. I will replace my fuel line first and see what that does. The line itself is not quality material and is not rated for any biodiesel so it degrades internally. This fuel line is the original from Airdog and according to them it's a proprietary line built specific to their requirements which sadly is false.

I've never heard of a pump firing in reverse but then again electronics can do funny things. Still the VP could not go into full reverse mechanically because it is engine driven but the timing could go pretty far off but I am not sure how far the ECM would allow it to go. Like I said electronics can do funny things.

For those who have mentioned a Fuel Pressure Guage, I am on it.  For the past two years, the Fuel Pressure Guage was something that I would constantly think "I really need to grab one of those" and then always have some BS reason to forget about it or blow it off.  Now I am reaping exactly what I sowed.   My Grandmother used to say "Never put off for tomorrow what you can do today" and danged if that lady wasn't spot on about this too.  It pretty much leaves me feeling like the quenticetial Moron.

Will definitely be adding one to the gear when I replace the VP next week.

Doc

For those who have mentioned a Fuel Pressure Guage, I am on it. For the past two years, the Fuel Pressure Guage was something that I would constantly think "I really need to grab one of those" and then always have some BS reason to forget about it or blow it off. Now I am reaping exactly what I sowed. My Grandmother used to say "Never put off for tomorrow what you can do today" and danged if that lady wasn't spot on about this too. It pretty much leaves me feeling like the quenticetial Moron.

Will definitely be adding one to the gear when I replace the VP next week.

Doc

Your far from a moron good buddy. The fuel pressure gauge will also help determine if a filter prematurely plugs also.

Off to Texas Diesel Injection this morning for full diagnostic and, most likely, VP44 replacement. 

I gave a lot of consideration to doing the work myself but feel the time crunch and family issues closing in.  With my Wife in the hospital right now, I just don't have time to turn wrenches.  Have to drive to a job on the 15th the next state over and want to know that I'm good to go without hassle.

Thanks to all who put in the great information to try and sort me out.

Doc

praying for your wife bud.  

 

Things always seem their worst until they aren't   

I will agree the temp sensor may be a little off but I do not believe it is that much. A stacked plate cooler can drop the temps a full 10 degrees but unfortunately I have yet to find one of appropriate size to accommodate 2.5 GPM and reduce the fluid velocity down to 1 FPS to adequately cool the fuel.

I do plan on changing fuel lines so it's possible the new pressure side line will help reduce the temps. I will keep everyone up to speed on that in my own thread in the future.

 

As a computer geek and overclocker i can tell you that you will not get enought to cool down the computer with a small heat sink, especially when the engine room is in the 200F range.

 

And for the record i have blown up two computers when the power supply went south, the diodes in the power supply went out and allowed the AC electricity into computer and after about an hour of testing the rig finally BSOD's and i nearly lost all of my data on my hard drives.

 

AC electricity and computers do not mix at all, and ive seen several people build gaming rigs around poor PSU designed system with multi rail PSU's that cannot feed the DC amperage to the graphics cards.

 

 

For the record i can get a quad core to cool down, but hitting 4.5Ghz on air cooling usually requires a good skill at lapping the CPU. and all of mine are lapped, althout the newer 45nm technology is nothing like the 65s it replaced.

Edited September 4, 20159 yr by pepsi71ocean

As a computer geek and overclocker i can tell you that you will not get enought to cool down the computer with a small heat sink, especially when the engine room is in the 200F range.

And for the record i have blown up two computers when the power supply went south, the diodes in the power supply went out and allowed the AC electricity into computer and after about an hour of testing the rig finally BSOD's and i nearly lost all of my data on my hard drives.

AC electricity and computers do not mix at all, and ive seen several people build gaming rigs around poor PSU designed system with multi rail PSU's that cannot feed the DC amperage to the graphics cards.

For the record i can get a quad core to cool down, but hitting 4.5Ghz on air cooling usually requires a good skill at lapping the CPU. and all of mine are lapped, althout the newer 45nm technology is nothing like the 65s it replaced.

You are correct and also incorrect. A properly sized cooler can drop the temperature up to 20 degrees this is sufficient for the end goal. The issue is velocity through the cooler must be very low and must remain in the cooler for enough time to properly remove the heat.

It is possible but the cooler line size would be fairly large nearing 1 inch. This becomes cost prohibited and may consume too much space. A stacked plate cooler will work but again size can be an issue.

Still the problem remain for any external cooler has to make contact with the circuit board. Which it can't. This why the whole thing is based on fuel cooling...

Still the problem remain for any external cooler has to make contact with the circuit board. Which it can't. This why the whole thing is based on fuel cooling...

Correct the VP 44 is cooled by fuel and the electronics are attached to the VP44 at the top regardless of how you see it heat rises so the computer is vulnerable. Keeping the overflow valve open on the VP44 with 14 PSI of pressure helps remove the heat but when your 150GPH pump cycles the fuel in the tank at a rate of 32 gallons every 12.8 mins the fuel at lower tank levels never sits long enough in the tank to cool off. Once at half a tank of diesel the pump can cycle 16 gallons in 6.4 mins this is where I have noticed temps to pick up. At a quarter tank(8 gallons) the lift pump will cycle the tank every 3 mins temps climb even further. This is why I brought up a cooler. If the VP44 case is even 10-20 degrees cooler this will help overall component longevity from the mechanical internals, to the electronics package bolted to and above the VP44. Fuel cooling is not the end all fix all but the big 3 have begun adding coolers to help alleviate this problem which is even worse for them due to HPCR systems pushing 21-29 KSI and line velocities even higher than 20 FPS. 

Another thing to consider is fuel return on the head is always hot and near engine coolant temp which over time heats up the fuel in the tank. 

I can give you a clue that Ed (Yankneck696) already has designed a awesome fuel cooler for these trucks that will improve fuel cooling performance. I was suppose to beta test the first series of cooler.... But his Dad died a of a stroke and there was personal issues occurring in the family so he's vanished off the radar for the time being. His design solved a bunch of different issues and had some bonuses too. I wish I could tell more but I can't.

I can give you a clue that Ed (Yankneck696) already has designed a awesome fuel cooler for these trucks that will improve fuel cooling performance. I was suppose to beta test the first series of cooler.... But his Dad died a of a stroke and there was personal issues occurring in the family so he's vanished off the radar for the time being. His design solved a bunch of different issues and had some bonuses too. I wish I could tell more but I can't.

Well family is more important. I have a little hydraulic background so I am aware of quite a few things in the fuel system that are easily corrected. 

 

Hopefully Yankneck696 will one day give us all an update.

Correct the VP 44 is cooled by fuel and the electronics are attached to the VP44 at the top regardless of how you see it heat rises so the computer is vulnerable. Keeping the overflow valve open on the VP44 with 14 PSI of pressure helps remove the heat but when your 150GPH pump cycles the fuel in the tank at a rate of 32 gallons every 12.8 mins the fuel at lower tank levels never sits long enough in the tank to cool off. Once at half a tank of diesel the pump can cycle 16 gallons in 6.4 mins this is where I have noticed temps to pick up. At a quarter tank(8 gallons) the lift pump will cycle the tank every 3 mins temps climb even further. This is why I brought up a cooler. If the VP44 case is even 10-20 degrees cooler this will help overall component longevity from the mechanical internals, to the electronics package bolted to and above the VP44. Fuel cooling is not the end all fix all but the big 3 have begun adding coolers to help alleviate this problem which is even worse for them due to HPCR systems pushing 21-29 KSI and line velocities even higher than 20 FPS.

Another thing to consider is fuel return on the head is always hot and near engine coolant temp which over time heats up the fuel in the tank.

Something else to consider. The only way to get your pump to move 150gph, or 32 gallons in 12.8 minutes, would be to run a 1/2" line straight from the discharge side of the pump back to the tank. There's no way it can circulate that much fuel through the small hole in the overflow valve. This is where we get pressure from. Now I haven't pulled the return line off to see how much it will flow but I bet it isn't 2.5 gallons per minute.