Engine/Transmission (1998.5 - 2002) Modifying fuel system so temperature input to VP44, 80* - 100*, your inputs.

[99guy]

Good thread guys.



Put a lp in my 01 last week. Still setting a 216 so it’s back to the shop for a new vp. Still warranty and we got the new in tank lp. Not sure about that, pressures are not as good as a new external mount lp from Cummins. This truck had dead pedal syndrome and low lp pressure.



In contrast when I purchased my 99 we found the lp was completely dead, vp inlet pulling a vacuum, don’t know how long it had been operating that way. Replaced the lp and have never had a problem with the vp in that truck. By the way the 99 is white and the 01 is dark so chalk one up for the white hoods.



A concern I have that may not have been addressed yet with a cooler between the filter and vp is the possibility of sending some foreign matter or particulates into the vp that might migrate out of the cooler or lines.

 

[Mundgyver]

I had that concern when I installed my cooler. I purged the system with about 1/2 gallon of fuel into a bucket at 15 psi then hooked it up. I did not see anything come out of the cooler I installed

 

[keimmmo]

Same concern here as well. I built a cooler out of copper tubbing like I had talked about earlier in the post. I built it like a radiator giving multiple paths for the fuel. I have 3 feet of 1/2 inch tube as the "tanks" and 16 feet of 3/8 tube as the pass tubes. I know without a doubt that there was crud inside the cooler from drilling and brazing!!!



I put on an automotive inline filter between the new cooler and the VP as a temporary. I'll run it a few weeks and remove it. That should give time to get the crud out of the cooler.



Fuel pressure was mentioned as a concern with the extra plumbing. There is no change as idle, cuise, or even heavy throttle. I lost a little at WOT. I hope that I will regain most or all of that when I remove the inline filter.



I have not way of measuring the temps except by touching the cooler. Yes, it is cooling the fuel noticably. While I'm sure it will help the VP, my real hope is for improved fuel economy.



Steve

 

[rweis]

This is an average of only 3 data sets to see if it tells us anything. Tank 1/2 - 1/3 full.



Data:

OAT 1,ff* 2,VP electronics bay* 3,VP return fuel* 4,Return fuel to tank* 5, tank body* 6



1 2 3 4 5 6

81 95 105 104 92 88

91 107 116 114 102 99

75 94 103 101 91 85

avg

82 99 108 106 95 91



Graph below of averages



ff about 17* > OAT

Electronics 10* > ff

input to fuel cooler 2* < electronics bay

output from fuel cooler 10* < input fuel temp

Tank body 4* < output from fuel cooler

Output from fuel cooler 4* < ff



Will be interesting to see what happens as tank reaches 1/8.



Why is ff so hot?

Is the ff contributing significantly to the input fuel temp to the VP?

Does this suggest definitely a fuel cooler between the ff and VP?

The ff has a lot of surface area, the input fuel enters and is contained around the hot outside before being drawn from the middle.

Should the ff have forced air from the outside to help cool it and therefore the fuel.

Is the ff showing the heat from pump pressurization?



With the fan on the fuel cooler I am barely able to reduce the fuel return to the tank temp below the ff temp.



Bob Weis



I have a RACOR 10 micron fuel filter as the fuel comes out of the tank. I may try bypassing the OEM ff for a run or two and see what that does to the fuel temps.

Just thought of this - I will add the RACOR ff to the temp spreadsheet for the fuel temp as it comes OUT of the tank. See if that contributes anything.

 

[rweis]

Something else to add to the pile:



Short 10 mile drive this am, only wanted to measure the RACOR 690 coming right out of the tank, the RASP body temp, the OEM ff temp.



88*, 91*, 100* a 3* rise for RASP effort seems reasonable, a 9* rise just for the body of the OEM ff? no work being done, absorbing engine compartment heat?, I think probably. Maybe the OEM ff is a major player in VP input temps.



This next week or two, I have a RACOR 690T (10 micron) as it comes out of the tank, I will plumb around the OEM ff and see what that does to temps going into the VP. Might duplicate the concept of puting a fuel cooler between the OEM ff and VP in a different way of really filtering the fuel right at the tank. Problems I see are if the OEM lp or any part of any line sheds anything the VP would be next in line. Not good! A 10 micron inline filter to the VP? Anyone know if there even exist a 10 um inline filter?



So maybe a fuel cooler before AND after the VP is the real answer. One pre cooler to take care of tank temps and heat absorbed by the OEM ff, one post cooler to take care of the heat generated by the VP.



Overkill?, maybe not. What's a reliable Vp worth? Not only that we have not even tested under hard pulling conditions over long hours yet (that normally generates "some" under hood temperatures).



It needs more temperature data over a couple of weeks to include towing next weekend. Also would help if others would take temperatures of whatever they feel they want and let us know.



Bob Weis

 

[Mundgyver]

I would think that a good heavy duty fuel cooler before the VP would be all you need. Simple, easy install, straight forward results.



For our fellow TDR members up North in the really cold country, the warm fuel going back to the tank would be a benifit in the winter in helping to prevent fuel gel problems and they could just cover the cooler when not needed in the really cold months.



For those TDR member in the South where temps are unreasonably hot (100+), then one ahead of the VP and one between the tank and the return line would be the way to go.



With 150,000 + turns on my VP now, just installing the cooler on the input to the VP was more than enough to bring up my comfort level.

 

[BigEasy]

I think Mundgyver just hit the nail on the head for the cooling of fuel...



You guys have done an incredible amount of research on this topic, and from a guy sitting back and watching, it seems to me that the main problem was overlooked. Not to belittle anything that was done, because cooler fuel is almost always better, but it seems to me that cooler electronics is the bigger target. It doesn't seem to me that moving the board(s) out of the pump to a better location with proper heat sinking and airflow would be all that hard...

 

[rweis]

We are still looking for someone that has actually looked into the electronics bay and willing to describe what is there. Are there contacts mounted to the bay itself? How is the fuel solenoid wired?, by wire?, by etched board? can you get into it enough to be able to solder to whatever contacts there are to construct a harness. What about the timing and the length of the harness? etc etc etc. BigEasy, "It doesn't seem to me that moving the board(s) out of the pump to a better location with proper heat sinking and airflow would be all that hard... ". Your on. That is the ideal direction. Go for it. Document the procedure well, because a lot of members are going to be interested in how to do just that.



Short of that is the direction the thread took, ie what we COULD do and COULD measure.



I think Mundgyver is correct about where you generally drive (N / S) OR how HARD you drive (WOT?) OR how heavy you tow (if you tow) which all effect heat. If I could always guarantee the tank temp would be 40* then ALL this is a mute point. If you generate little heat, then little fixes, a lot of heat, then more fixes. And of course what you individually are willing to live with.



The guys that tow long and heavy for a living are probably the best example of a test bed to work toward.



As for me I am going to continue to get the VP input fuel as low as possible (FL) and maybe not have to worry about heat soak. I will continue posting this thread as I find things that lower the VP input fuel temp (ie I'm not done yet).



Mundgyver "For those TDR member in the South where temps are unreasonably hot (100+), then one ahead of the VP and one between the tank and the return line would be the way to go. ", ... . well, how about moving the ff away from the engine heat? and in the moving air flow?, use it as a heat remover rather than a heat adder, depends on where and how you drive.



Bob Weis



Bob Weis

 

[darkhorse]

Moving the electronics is what I'm interested in. I want to be able to run warm fuel so that I can run straight veggie oil. Greasel has done a great job developing conversions for a variety of vehicles to run on SVO but their experiments with an '01 Ram were torpedoed by electronics failures in the VP44 due to the warm oil.

 

[Gary - K7GLD]

OK - Just returned from our 1200 mile or so RV tow from our home in eastern Oregon to the Oregon coast and back - lots of good testing on a couple of issues.



First, the value of my added VP-44 airflow ductwork and fan seems to have a small decent potential, but needs further refinement for best results - or a somewhat better fan. As it stands (with my setup), it WILL deliver about a 5 degree reduction in VP-44 temps shortly after engine shutdown, improving to 10 degrees after about 15 minutes - I plan to set my fan turnoff delay for 30 minutes, at which point the underhood temps start dropping on their own.



On to the VP-44 itself...



Actually, my results while towing pretty much duplicate Bob's longer trip readings. The VP itself seems to max out at about 138 degrees - and WILL rise higher with underhood heatsoak if the duct fan is not left running at engine shutdown - and in that case will rise to about 150+ degrees in the 90 degree ambient temps I was experiencing at that point in my testing. My fuel tank level typically was at about ½ for the above temp readings.



I found (as reported in another related thread) that down-the-road underhood temps in level terrain rarely rise more than 5 degrees above ambient - and even in routine grades while RV towing, I rarely saw above a 20 degree rise. Over the road underhood temps are not a problem - HEATSOAK after engine shutdown IS!



For my money, the advantage of improved fuel flow to the VP-44 is of primary benefit - probably followed by a fuel cooler immediately ahead of the VP-44 - and for underhood heatsoak protection, some sort of outside airflow. At least that's the way I see it at this point.



This will be it for me in this thread, and the TDR. My subscription is about to expire, and I'm sort of burned out. I've been doing this experimentation bit and photo essays for quite a while now, and enjoyed it - but sometimes time and annoying pointless side issues take their toll - so I plan to take a break for at least a little while.



If any feel need to contact me directly for added info or comments on this thread, I can be reached direct at:



-- email address removed --



Take care, and best wishes to all!

 

[rweis]

Well Gary, BEST of LUCK! Sorry to see you hang it up for a while, but I understand your position. Lots of folks have the answers but none of the grunt work proving it.



In short, I am going to get rid of the OEM ff by puting a 8um in line ff (designed for diesel on the suction OR pressure side of the RASP pump) on the frame as the last thing prior to going to the VP44 (on the pressure side of the RASP). Get rid of the OEM ff all together. Along with my RACOR 690T (might have to put a fuel heater & WIF sensor in the RACOR 690, easily done) for water seperation and pre filtering right at the tank should get rid of another 10* of VP fuel temp. I am seeing at the RACOR 690T, ambiant MINUS (-) 5*, then +3* for the RASP. I can cool the return fuel (right now) to -4* from VP output temp and should be able to do -10* to -14* after I get rid of the OEM ff. That should take care of any low tank feeding to the VP. The more I feed it the cooler it should get down to ambiant - 10* to -15* (100* -10* is sure a heck of a lot better than 100* + 12*).



To get the VP cool like your ducting I am going to do a 4" bilge blower by Attwood (240 cfm) ducted to exit under the runningboard and suck the heat out of the engine compartment rapidly. One on each side if need be (~500 cfm should do it ). Run them for 1 or 2 hours after shutdown (10 a/h total). Mount the intake right OVER the VP so it gets cool outside air almost immediately. Mount the other one over the alternator to vacuum as much heat out as fast as possible without melting the bilge blower from the turbo. I think it will start the underhood temps down in less than 2 minutes. And remember the VP internal fuel feed was -22* from what it use to be, so the VP44 should be cooler from the start.



IF that does not work. I am talking to a body shop to put 2 powered (fan assisted) hood scoops, one over the VP, one over the alternator with 6" holes in the hood for the post shutdown ventilation. Use the heat to exit itself, or if the fans are needed then power vent the whole damn hood. That would drop the shutdown underhood temps in less than 1 minute to ambiant in 5 minutes.



GOOD LUCK my friend and I will email you the results.



Oh, BTW the oil filter project is on going, 6. 5k right now and looking pretty good.



I "ain't buying another Vp on my nickel because of electronic failure from heat", lol



Bob Weis

 

[GIT-R-DONE]

Question: Is there an in-line fuel temperature gauge you can buy? Just wondering how you were getting the actual fuel temps?



After reading all of this thread, sounds as if it would be good to actually cool both prior to the VP and prior to the tank. The air duct idea buy Gary also sounds good. Is there any way you could use duct work also to cool the OEM FF?



Also, since your heat soak is a factor here, is there any way to use the heat insulating blanket around the area of the VP?

 

[rweis]

I am using a temp gun right now. I have a 30 - 150 gauge coming with inline sensor.



I think the OEM ff is one issue because it is large surface area, incoming fuel is on the outside of the internal filter between the filter and the case and directly subject to engine compartment heat through the metal body of the ff. IE why I'm looking at ditching the OEM ff.



You could conceively cool it by flooding it with outside air. I do not know what wrapping it in a blanket would do. Maybe hold heat in?



You could probably put a blanket between the VP and the block to help keep the VP cool. That could certainly help. Interesting possibility.



I have a fuel cooler and fan on the return from the VP/inj to the tank. I have an ETC and I think difficult to mount a 2nd cooler with fan up front due to transmission OEM cooler. One of the reasons I am looking to shed heat by other means.



I am strongly looking at a marine bilge blower for the after shutdown heat soak issue on the VP.



Some good ideas,



Bob weis

 

[Lsfarm]

Heat cycles

Heat cycles



Hi Bob, thanks for all the time and effort to read temperatures and experiment with your truck.



I have a few concerns:



I question that a heat soak after shut down is causing failures. I believe you took readings off of the ECM as well as the VP computer. Both had significant heat rise after shutdown. But we have virtually zero ECM computer failures.

I believe that the computer and VP is just poorly designed.



Certainly the heat cycles aren't helping anything, but it seems that the ECM is designed to be bolted to the engine block and recieves the vibration and heat cycles and survives.



I'd be very curious to see what the VP's computer temperatures are when the lift pump is failing. There have been numerous VP failures on trucks that have plenty of fuel pressure [fuel cooling] and that have not been run out of fuel. I hope that there will be an improved computer for the VP some day.



I keep my fuel level above 1/4, 3/8 most of the time, have had a pusher pump and good fuel pressure since 12K miles, and I still lost my VP at 50K. It is just a poor design in my opinion and experience.



There are plenty of VP's in hot climates failing, and plenty in cold climates failing, in fact I believe the VP powerd trucks in Alaska have a high failure rate because of the winter fuel up there. [poor lubrication from #1 fuel]



How about a poll to track the climate of failed VP trucks??



If the heat cycles are the cause of the VP computer failures, shouldn't there be a trend to show higher failure rates during the summer, and especially in the hotter climates in the southern states?? I would think that the VP's would be failing all over the place in LasVegas, Tuscon, etc. ??



I'm just frustrated by the whole reliability issue. I had believed that what I do to keep fuel supply to my VP should have kept it alive, but it didn't. I had dead pedal, 0216 code and failure to idle. At only 50K miles. I know that the 'diaphram' in the VP has been redesigned, and this should help reliability, time will tell.



Oh well I guess a $1000 pump every 50K isn't too much to put up with.



Greg L

 

[Texas Diesel]

Heat cycles



I keep my fuel level above 1/4, 3/8 most of the time, have had a pusher pump and good fuel pressure since 12K miles, and I still lost my VP at 50K.

Is it possible that the VP's are failing due to low lubricity (as you pointed out earlier)? This will get worse when the ULSD hits...



I used 2 cycle oil in my previous 24V for 120,000 miles. Stock LP and lines, and only one LP replacement. It ran like a swiss watch.



*IF* low lubricity is the problem, or 80% of the problem then you can keep the VP in a bucket of ice water and it will still fail.



I'll keep adding 2 cycle oil and keep my fingers crossed ( I have a fuel after cooler )

 

[rweis]

I had a VP failure @ 52k, but



I had Stynadyne PF in every tank for the lubricity problem (& pour point etc).



I think I might have caused the problem by regulating the psi to the VP. That MIGHT have lowered the volume and not enough cooling. I have a RASP now and pleanty of fuel and pleanty of pressure.



I also had the origional 02 version of the VP which I think was suspect. There was a poll by years and the 02's had about 50% of the failures out of about 75 responders.



The replacement was this summer from DC, so I should have the updated version of the VP. They also replaced the OEM lp.



I'm trying to drive the longevity of the VP as far out as possible with pleanty of fuel, cool fuel (<100* so far), minimize the heat cycles of the electronics, not run my comp (only use it as a boost fooler), lubricate the fuel (Stanadyne PF), and ???????????



My objective is 100k - 150k miles



The problem is RELIABILITY. If I can't take it on a long trip and it be reliable, then that is a problem.



Bob Weis



Texas Diesel Could you describe the fuel after cooler? Are you the member that put a cooler between the ff and the VP?

 

[keimmmo]

Greg L,



The original VP on my truck failed at about 40k. I have 124 on the truck now and it is running fine. The replacement pump gave better fuel economy and more power than the original. I know the VP is still a weak link. But, I have to wonder if there were a lot of them that had special problems right from the factory.



Steve

 

[Graphic man]

I am working on a Cooling project of my own now, and will post pics and info as soon as my RASP gets here



Scott

 

[RClark]

Texas Diesel-how much 2 cycle oil do you add?

 

[keimmmo]

Bob,



I was looking at my 01. 5 today. That filter sure DOES get hot mounted to the side of the motor! I think it is acting like a heat sink and drawing heat off the head. Aluminum will do that very well!



I was thinking that if we could mount the filter lower and away from the motor, it might not do miracles, but it HAS to help. I see another benefit as well. As it is with my truck, I go from the fuel lines mounted on the frame to the factory filter housing then back to the frame for the fuel cooler in front of the radiator and back to the VP. If we can mount the fuel filter on the frame, it would get away from going back and forth between the moving motor and the solid frame with the fuel lines... a potential problem.



I see a couple of holes in the frame just outboard and below the factory filter position. It doesn't look that hard to me to build an angle iron/plate steel adapter to mount the filter housing on the frame. That would allow you to put a nice BIG heat shield between the motor and filter housing. It would even have it close to a source of air for cooling it if you desire.



I haven't tried to pull the housing off the motor, but it looks to me like the only thing that will need to be extended will be the wiring harness for the "water in fuel" sensor. Shouldn't be a big deal.



I am SERIOUSLY considering this modification myself!!! However, I do not have a way to measure the temperature differences other than by touch. Please consider this modification so you can measure the difference in temps to let the rest of us know if it is worth the trouble.



Thank you for your work on this project. I really appreciate your efforts.



Steve