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

[RAJohnson]

I to have a FASS, and after reading this entire post and watching it for a few days. I posted a question hear on TDR concerning the fuel heater and where it was located. I was informed that it was part of the OEM ff which I had removed when I installed the FASS. Being from the northwest I started to become concerned about winter fuel gelling up in the colder months. So I reinstalled the OEM ff. So my FASS is now going to the OEM ff and then to the VP44, Two filters have got to be better then one, Right? Oo. I did use the fiber washer's that was posted hear not to long ago to help separate the ff from the intake manifold. I also run stanadyne in the winter months just because I did freeze up a 95 CTD in the winter of 96, -20 below going 50mph. Learned a lesson back then, and ever since I have run a fuel conditioner.

 

[Fishin Guide]

I to have a FASS, and after reading this entire post and watching it for a few days. I posted a question hear on TDR concerning the fuel heater and where it was located. I was informed that it was part of the OEM ff which I had removed when I installed the FASS. Being from the northwest I started to become concerned about winter fuel gelling up in the colder months. So I reinstalled the OEM ff. So my FASS is now going to the OEM ff and then to the VP44, Two filters have got to be better then one, Right? Oo. I did use the fiber washer's that was posted hear not to long ago to help separate the ff from the intake manifold. I also run stanadyne in the winter months just because I did freeze up a 95 CTD in the winter of 96, -20 below going 50mph. Learned a lesson back then, and ever since I have run a fuel conditioner.

Some guys just pull the filter out of the housing and that way the heater element will still work.



Dave

 

[rweis]

I think that points to running the FASS (in your case) directly to the VP in the "warmer" months and to the OEM ff in the "cooler" months.



The idea of taking out the OEM filter sounds reasonable if you have sufficient other filtering and using the OEM ff as the fuel heater.



In your case, from the FASS a long enough hose that can hook up to the OEM ff directly and also to the VP directly (one or the other). In the summer when the heat is the problem, run directly to the VP and bypass the OEM ff. In the winter when you need the protection of the fuel heater, run to the OEM ff sans filter.



You could even run the input line to the bottom of the OEM ff so it is easier to get to for the change over since there would be no actual filter.



All it really amounts to is NOT insulating the OEM ff, because when you use it you WANT the extra heat. A longer fuel hose that will screw on the OEM ff or the VP when you think the weather requires it, and a couple of hose AN-6 screw in plugs to plug off the one you are not using.



Just an idea.



I wonder how many VP44's die in the colder months and there is anti gelling additive being used and not the problem of the electronics overheating.



Bob Weis

 

[Fishin Guide]

I think that points to running the FASS (in your case) directly to the VP in the "warmer" months and to the OEM ff in the "cooler" months.



The idea of taking out the OEM filter sounds reasonable if you have sufficient other filtering and using the OEM ff as the fuel heater.



In your case, from the FASS a long enough hose that can hook up to the OEM ff directly and also to the VP directly (one or the other). In the summer when the heat is the problem, run directly to the VP and bypass the OEM ff. In the winter when you need the protection of the fuel heater, run to the OEM ff sans filter.



You could even run the input line to the bottom of the OEM ff so it is easier to get to for the change over since there would be no actual filter.



All it really amounts to is NOT insulating the OEM ff, because when you use it you WANT the extra heat. A longer fuel hose that will screw on the OEM ff or the VP when you think the weather requires it, and a couple of hose AN-6 screw in plugs to plug off the one you are not using.



Just an idea.



I wonder how many VP44's die in the colder months and there is anti gelling additive being used and not the problem of the electronics overheating.



Bob Weis

My vision of a quick change through filter/ bypass filter would be a simple 6 AN union. I have adapters in my FF housing and It would be easy to remove the FF housing and just use a union in it's place. Would be 15 minutes tops. And if you only do that twice a year, no biggie. With less connections, there is less of a chance of leakage and it is mechanically simpler.



Dave

 

[dknoch]

I have had 2 vp-44s die on me. The first was in the fall. This was due probably to a dead lift pump had code 0216. Took the truck on a small trip, about 5 hours each way, pump started acting up coming home. After new lift pump and vp-44, I installed a pusher pump. Lift pump died again with the pusher pump, so I installed a FASS and plumbed it to the original ff housing w/out the filter. After about 14-15 months, in early spring, VP-44 died again, started acting up only about an hour from home. Still had great fuel pressure and I was using an additive every tank. Can't remember the code this time, not the 0216, something different.

 

[rweis]

Well, to add to the confusion I took out my OEM ff and now have a inline ff down on the frame, no OEM ff at all (really opens up the engine compartment over there ).



1 drive 20 miles, but here is the data, late afternoon (1700 hrs, oooops, 5 p. m. ).



OAT 88* as measured by the overhead console temperature probe. TV weather broadcast was 90* (I will add touch temperatures to help those who use the touch method to take temperatures)



All values while engine is running at idle after the drive.



Tank temp by heat gun 3 places averaged 94* (not warm to the touch)



Fuel input temp to the VP 96* ( I have the RASP system, but quite a bit of plumbing to the RASP and then to the VP, line friction may have something to do with this, and probably a degree or so for the pump pressurization)



Brass T where the fuel temp probe is (location is on fender side along side the PS pump fill cap orientated front to back) by heat gun 109* (very slightly warm to the touch)



VP electronics cover by heat gun 113* (very slightly warm to the touch, not uncomfortable at all)



VP / injector return line H7B fitting back by the tank 109* (very slightly warm to the touch, not uncomfortable at all)



H7B output fitting back to the tank vent line with 1000 cfm fan running 100* (not warm to the touch)



The first thing I notice is there are differences between measuring a metal fitting and the actual flowing fuel temperature and the resin fuel tank material.



I'll gather more data and post it as I do.



Bob Weis

 

[jjohn]

Well, to add to the confusion I took out my OEM ff and now have a inline ff down on the frame, no OEM ff at all (really opens up the engine compartment over there ).



Only 1 drive, but here is the data, late afternoon (1700 hrs, oooops, 5 p. m. ).



OAT 88* as measured by the overhead console temperature probe. TV weather broadcast was 90*



Tank temp by heat gun 3 places averaged 94*



Fuel input temp to the VP 96* ( I have the RASP system, but quite a bit of plumbing to the RASP and then to the VP, line friction may have something to do with this, and probably a degree or so for the pump pressurization)



Brass T where the fuel temp probe is (location is on fender side along side the PS pump fill cap orientated front to back) by heat gun 109*



VP electronics cover by heat gun 113*



VP / injector return line H7B fitting back by the tank 109*



H7B output fitting back to the tank vent line with 1000 cfm fan running 100*



The first thing I notice is there are differences between measuring a metal fitting and the actual flowing fuel temperature and the resin fuel tank material.



I'll gather more data and post it as I do.



Bob Weis

If only Dodge had put this much effort into this issue!

Thanks Bob

 

[rweis]

I like the idea of leaving the OEM ff in place without a filter in it for winter months fuel heating.



I have the inline ff (8um) permanently mounted just before the VP. As an a side note: My input psi to the VP dropped 1 psi when I changed the OEM ff to the inline ff. I think it is because of better volume flow and less restriction. The inline ff has 12AN ( ) 1 1/8" ports and flows 90 gpm vs the 45 gph of the OEM ff. I also use to be able to see the slight ticking pulsing of the pre and post OEM ff fp from the RASP as the gears pumped fuel at idle. Now I do not see any pulsing of the pre or post inline ff fp at all. Not sure why, but the only thing different is the OEM ff is out and the inline ff is in.



I'm thinking of puting the OEM ff back on without the filter for fuel heating purposes only. The OEM ff could have an input and output lines hooked up full time, but the outlet line would have a ball valve on it. For winter, just open the ball valve from the OEM ff and close the ball valve of the straight line from the inline ff. No fuel filter to change, only using the fuel heater feature as well as the engine compartment heat picked up by the OEM ff body.



I took a good look at the OEM ff today. That thing is a casting of totally aluminum (except the screw top of course). Great heat conductor. Just use it when you need it (valve open), and not when you do not need it (valve closed).



Bob Weis

 

[rweis]

More data,



After a week I am finding that the RASP contributes 2* to the temperature.



I only have a 2 T brass setup under the hood (one T for the temp sensor connected in series to another T for the RASP bypass back to the tank vent). However I find it gains 6* - 8* based on how the engine compartment is warming up.



The fuel H7B and fan removes 10* and that is repeatable measurable time and time again.



I went to Home Depot and am going to wrap the engine compartment fittings in the split foam wrap like you wrap plumbing in and then tape it with foil reflective tape to try to get this 6* - 8* out of the equation.



Once the engine compartment heats up the 2* rise continues to 8* - 10* (ie a 6* - 8* additional rise). It does not start further up until the engine compartment warms up. I drove 30 miles with the hood partially open to see if I could controll the additional heat rise and I could limit the heat rise from OAT to 2* over a longer drive with better under hood air flow.



Obviously you can not drive with the hood partially open, but it proved that the heat rise was from engine compartment heat. I am going to try to insulate the fuel system under the hood from the heat with the pipe wrap and foil tape. I have already taken out the OEM ff.



So far the max temp rise has been 10* after a 45 mile drive. It rises to OAT +10* and stays there. If you force the under hood temp up the fuel temp will go up correspondingly, and when the under hood temp comes down the fuel temp will come down correspondingly. Under hood temp gauged by radiator temp rising and then settleing back down to previous readings.



I will report back as I make changes.



Bob Weis



So far this past week with OAT at 90* no fuel to the VP has been more than 100* input (cool to the touch). I think we are gaining on it. I tow the RV 100 miles in 3 weeks and will see what happens then.

 

[GIT-R-DONE]

Is the underside of your hood insulated? I was wondering about that, for those of you doing these tests. Or even if it makes a difference.

 

[rweis]

No, the underside of my hood is not insulated.



Bob Weis

 

[rweis]

more data,



I do not have the OEM ff installed at all,



I have a inline ff down on the frame before the VP44.



All I had in the way of fuel lines in the engine compartment were lines comming up to the VP and a RASP bypass return line. These two lines were in 2 brass T's (connected together) for 1/4 npt.



What I was seeing is a 2* rise from tank temp initially and as the engine compartment warmed up I would see another 6* - 8* increase in fuel input temp. Tonight I insulated the brass T's and the input fuel line to the VP and the input fuel line comming up from the frame with the split foam pipe insulation and then wrapped that in air conditioning foil duct tape to reflect as much heat as possible and keep the engine compartment heat off the fuel lines.



The result with a 40 mile drive (normal drive is 17 miles) was that the fuel input temp did not go above the 2* above tank temp. There was no engine compartment heating of the fuel system at all.



Also I am finding that the VP44 and injector return line raises the fuel temp by 14*. I had a steady 88* tank, 90* input to the VP, and 104* return from the VP to the H7B fuel cooler back under the bed. I stopped 3 times out and 3 times back to check the temps with a heat gun and the temps were all within 1* of each other from the same location.



Now what this tells me is you have to get rid of at least 14* in your fuel system or the tank will eventually get warmer and warmer degree by degree.



My H7B and 1k cfm fan will lower the fuel temps by 10* (ie 104* in 94* out) but I still need to get rid of 4* more to keep from heating the tank fuel above OAT. The tank was at 2/3 full during this run. As the tank runs lower it will be interesting to see the effect on the input fuel temp. My guess the fuel temp will slowly rise degree by degree. I also dump the return fuel into the tank vent line instead of the fuel cannister.



More data as I collect it.



Bob Weis

 

[rweis]

Add a new twist:



I wanted to monitor the case temp of the VP44 so I went to WalMart and got an inside / outside thermometer and stuck the outside probe on the electronics bay cover toward the top and rear of the Vp44 electronics bay cover.



Now I know the outside case temp is not the internal temp.



Conditions:

OAT 85*, short 10 mile drive, 2/3 tank, fuel input temp 87*, electronics bay case temp while driving 113*, electronics bay case temp max after shutdown 127* (the thermometer will record min, actual, max until cleared and reset). While driving I had the ocasion to be at idle for about 5 minutes. The Vp electronics bay case temp started up from 113* and peaked in those 5 minutes to 118*. As soon as we got underway again the temp slowly came back down to 113*. I think this means airflow under the hood is greatly enhanced with forward movement (now THAT is rocket science huh, ) and, I think also that when the Vp44 bypass opens on higher engine speed (I have a RASP, which idles at 14 psi, and runs at 17 psi) there is some effect of bypass that may include cooling the VP44. I'll have to try a high idle (ie > 14 psi) and see what happens with that to try to isolate air flow and fuel flow.



Oh, I also installed the bilge blower on the APPS cover (toward the intake horn) to see what trying to suck hot air out (135 cfm) of the engine compartment will do to the heat soak issue. Can you suck the hot air out fast enough to keep the heat soak to a minimum, say OAT + ????. OR is it better to blow OAT on the VP44 to cool it specifically and control its heat soak that way.



Gary installed a blower that blows on his VP44 so he is testing that approach to the heat soak issue. I still email with him, I think he dropped TDR because some of the "discussions" and his blood pressure were not "compatiable", but he is a really good meticulous experimenter and data gather and actually "does" the experimentation.



Comments ALWAYS welcome,



Bob Weis

 

[rweis]

More data:



OAT ~85*

The VP44 shutdown heat soak seems to be fairly constant at ~ 130* measured on the cover to the electronics bay. Internals are probably hotter than ~ 130*, how much I do not know (10*?).



The concept of trying to lower the engine compartment after shutdown temperatures by sucking out the heat is not working. Might be the amount of heat given off is too much for the bilge blower to suck out (135 cfm). This approach is not lowering the VP heat soak enough (~ 110* range, internals ~120*?)



I am going to try Gary's approach of blowing OAT on the VP44 and see if I can flood it with OAT and keep its heat soak down.



Bob Weis

 

[GIT-R-DONE]

Thanks for your effort, Bob, and all the others participating in this thread. This is one of the best threads going that I have seen for a LONG time. Very informative and interesting.

 

[rweis]

More data:



Normally I run at 1400 rpm (best fuel milage) on the way to work. As reported above the Vp electronics bay cover temp (EBC temp) was 113*. This afternoon on the way home from work I took the Interstate for an extended didtance to see what if any difference there was in EBC temp.



The first run was in O/D as you would normally drive the interstate. @ 70 mph ~ 2000 rpm the EBC temp stabilized @ 118*. I drove about 30 miles. Tank @1/2, OAT 90*, tank temp 98*, VP fuel input temp 100*.



The second run. When I tow my 5er I tow O/D out so I have more rpm and torque. @60 mph ~ 2400 rpm the EBC temp stabilized @ 122*. The same 30 miles. The same tank @ 1/2, OAT 90*, tank temp 98*, VP fuel input temp 100*.



Both runs were not loaded (ie empty).



When I got back onto secondary roads and O/D in and slowed down to 55 - 60 mph (from the 2400 rpm run) the EBC temp dropped right back down to ~ 116*. The drop was like in 1 minute.



I had always assumed that more rpm meant more fuel bypassed as well as available and a cooler VP. The slower mph but higher rpm run netted higher VP EBC temp. Now the temp difference is only 4*. When I slowed down to secondary road speed the EBC went to 116*, and when I tried my 1400 rpm 51 mph it netted the same 113* as I have seen on several days. (I drive @ 1400 for fuel economy. (I know the overhead console is not numerically accurate, but the best mpg and keeping the T/C locked in O/D is 29 - 31 mpg on level road (turbo whine pitch constant ie steady state rpm)). The T/C shifts into O/D @ 1200 rpm and I add 200 rpm to keep it locked in O/D to compensate for any terrain variation)



The coolent temp on the interstate runs was 2 needle widths (~1/8") below 190* mark on the gague (180*? (I have a 180* thermostat)). The coolent temp on my work drive @1400 rpm is normally about 3 needle widths (~3/16") below the 190* mark on the gauge. (Yes it does go up to 190* as the thermostat warmes up then as the thermostat opens it drops to 2 needle widths below, then as it stabilizes it drops to 3 needle widths below)



I appears that more rpm = more VP temp, less rpm = less VP temp. My RASP input psi to the VP is constant @ 16psi at any rpm above about 1000 rpm. I put Stanadyne PF in every tank since tank #1 for extra fuel lubrication.



I have read that the Vp is built with extremely tight internal tolerances. The differences in rpm and temp seem to bear this out.



When I got home I checked the under hood heat evacuation system again. The EBC temp went to a max of 129. 5* from 111*. After 1 hour, 125*, after 2 hours 112*. OAT 85*. Clearly this is not the way to go.



I will change the under hood air blower to blow directly on the VP EBC anytime the ignition circuits are energized and for at least 1 hour after shutdown. Maybe the use of OAT to cool the VP rather than under hood temp air will help keep the VP cooler. We'll see and I will report those results.



I will tow my RV in about 2 weeks about 100 miles each way and will add those results then.



Bob Weis

 

[BDanner]

Bob, thank you for the updates and your work in this area. It may appear boring and pointless to many, but your research is of great help to those of us who beleive that not only low pressure kills VP44's. It was proven on the Fedex vehicles with CTD's warranted by Cummin's that heat soak kills the onboard circuitry of the injector pump. We all know that low pressure from dying LPs attack the IP diaphram.







Interesting meeting this past sunday while towing my 15K gooseneck. We pulled in for fuel in Cumberland, MD and a TDI with Indiana tags slipped in next to us. I had my hood up and the driver of the TDI could not help himself, he had to come for a peek under the hood and quiz me on my setup. This fellow repeatedly said "good" as he saw my 4" exhaust, BHAF, Banks HI-Ram intake, FASS with no OEM filter and missing LP.



Turns out this gentleman was a Senior engineer for CUMMINS in Cloumbus,IN! His wife came out of the station about the time I heard this not so good familiar sound of fuel overflowing and splashing on the pavement. Have you noticed alot of those truck stop nozzles do not shut off? I sprinted around the corner and removed the fuel nozzle from the TDI that was getting a fuel bath. All his wife said with rolled eyes was "talking diesel again?", after she glanced over at the 3500 dually with the hood up. We had a short delightful conversation about VP44s and the topic you have been addressing, as well as the low pressure issues. When I told him I was a TDR guy he responded with a respectful "Ahhh".



Keep up the posting of your results!



Bruce in Northern Virginia

 

[rweis]

We had a short delightful conversation about VP44s and the topic you have been addressing, as well as the low pressure issues.



What were some of the comments? Might lend some insight as to direction to point to for lessening the impacts on the VP44.



Bob Weis

 

[SKneeland]

heres a pic of my new "fuel cooler"

total investment: trans cooler from Mopac $65 cdn

hoses & fittings $120 cdn

3 way ball-valve on the bottom for normal flow(through cooler) or bypass(cold weather)



top cross is plugged off until i pick up the last piece to attach my pressure sending unit and possibly temp unit

 

[Graphic man]

Bob,

are you running a big fuel line kit with your RASP ?