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

[Gary - K7GLD]

Does the ECM need to be mounted to the block at all? I haven't looked at it lately but couldn't it be moved to the frame, or someplace, using the exsisting wiring harness?

Along the same lines. . if someone made a jumper (where's timbo?) to extend the harness you could mount the ECM anywhere you wanted. I was thinking under the cab or even inside the cab.

Anyway... just thinking out loud. As Gary said you don't hear of too many problems with the ECM but it does seem like a bad spot to mount a computer.

Mike

Supposedly, the ECM gets it's grounding thru the connecting harness - so the attachment to the block isn't necessarily required for that function - still, I'd bet there IS an internal ground to the frame/case of the ECM, and then on into the engine block. In any event, I'd plan on a direct ground strap from the ECM case to the engine and body/frame of the truck, just in case.



As to ECM failures, seems to be a bit of an increase in failure rate recently - after all, these have been on the road for a while now, and seeing some pretty wide hot/cold cycles - all of which is the reason I have my own spare ECM's...

 

[rweis]

Maybe add standoff's to the existing mounting bolts and stick a 2" block of styrofoam between the ECM and the engine block. Maybe just suspend the ECM in mid air between the block and the fender well? It would get more air than slapped up against the block.



Bob Weis

 

[Gary - K7GLD]

Maybe add standoff's to the existing mounting bolts and stick a 2" block of styrofoam between the ECM and the engine block. Maybe just suspend the ECM in mid air between the block and the fender well? It would get more air than slapped up against the block.



Bob Weis

While working on the heat shield for my ECM, I had planned to also use some fiber washers to reduce heat conduction from the fairly large block contact pads on into the ECM frame - but it was too tight and difficult to get them in place, so gave up for now - but remember how effective that was on the fuel filter canister further up in this thread? I'd bet it would be just as effective on the ECM as well!

 

[rweis]

What I am thinking is getting 2 1/2" same thread screws and putting a 2" styrofoam block between the ECM and the block and tighten against the styrofoam block for tension, or maybe put some fairly heavy springs between the ECM frame and the engine block that are about 2" long to get the ECM off the block.



Maybe valve springs? something like that, a trip to HD looking at their spring drawers should yield something. Some kind of a compression spring. I remember there is a compression spring on some door retainers that cushion the door when it tries to open too far like when the wind catches it. Something like that. Get the ECM off the block a couple of inches, or just hang the thing in mid air from the cowel lip. Something to get rid of the heat.



The ECM ground should come in the wire harness I think.



Bob Weis

 

[JohnBoy5]

ok so i have been looking over all this and have seen lots of great ideas. I know i missed a few post but where were the most gains made, cooling the return or supply fuel. what about people with a fass pump that have a retun from the fass system, maybe a cooler from the reurn on the back of the engine and a cooler on the return of the fass system.



Has anyone found a chiller that runs on 12v dc? i am getting ready to have to install a new vp44 and would like to get some protection in place before i do.

 

[rweis]

This is what I have experienced over about 4 years of monitoring the fuel:



Put a temperature sensor on the input fuel to the VP44. Fuel temperature depends on 2 things (courtesy of Gary, who proved the second one to me).



First is the engine rpm. the faster the rpm the more heat the VP44 emparts to the fuel.



Second is the gross weight of the truck & or what you are towing. I have never figuered out how the VP44 knows the load is greater. Maybe it is the advance or something, but I know for a FACT that the heavier the combination the more heat the VP44 emparts to the fuel (thanks Gary).



I have been monitoring the fuel temp for 35k + miles. I NEVER let it get above 120*. The problem is hot fuel I THINK will losen the solder on the VP44 computer and that is what fails, poor computer chip connections.



Findings:

Normal empty truck, OAT + 10* to 15*

Towing a 12. 5k 5er, OAT + 20* to 25* if fuel temp is getting high, slow down to adjust fuel temp based on rpm i. e. speed.



MY configuration:

RETURN LINES:

From the T on the engine I replaced the return lines with 3/8" ID fuel lines. See a previous post about the TINY 3/32" ID plastic flex line that comes off the engine T to the steel frame fuel line. You could not get 31. 5 GPH (70% of fuel is returned to the tank as cooling fuel. Max 45 GPH will go through a VP44) through there if you pressurized it, which it is not. Here is a major flaw, the small ID of the flex return line. Ok, you replace ALL the return lines.

TANK:

The HOT fuel is dumped into the pickup cup in the tank. You need to return your fuel to the tank as a whole to mix with the total tank. I return mine to the filler tube. I also put in a DrawStraw to draw fuel from the tank as the fuel canister is a poorly designed mechanism and has several sharp bends of small diameter fuel line. You can also replace the fuel level sensor if you want but that is another thread.

FUEL COOLERS:

I mounted 4 frame mounted racing fuel coolers to help cool the fuel to ambiant temp. They add about 10. 5 feet of finned cooling on the way back to the tank.

VP44 BLOWER:

Thanks again goes to Gary. A bildge blower from a boat parts store mounted below the bumper and ducted with dryer flex hose to the VP44 computer chip area. Interesting thing I found out is below 40 mph it is insignificant except it keeps cooling air directed on the computer chip, above 40 mph the ram air makes the VP44 a fuel cooler than a fuel heater. Weird. However after shutdown, the engine heat soaks the VP44 chip. Engine temp 180*, danger area for the chip > 120*. The blower floods the VP44 with OAT and keeps the VP44 (and TPS if you drill a couple of holes in the TPS, but that is another thread, well actually I don't have a TPS $$$, I have a $3 microswitch instead, another thread. ) cool because of the OAT flood keeps the engine heat off the VP44.



I never could get the fuel temp to my specifications of 80* - 100*. However I can keep it at OAT +10* empty or OAT + 20* towing, and keep it from being damaged by engine heat soak. I have been about 35k - 40k miles this way. Actually, I do not remember when I was under the truck last trying to figure out a problem.



Bob Weis

 

[JohnBoy5]

have yall seen this sweet little setup Fuel Cooler

 

[rweis]

That would work GREAT at cooling the fuel. It was not available when ...



Items still need addressing:

Fuel flow rate back to the tank - might be addressed by colder fuel.

Poor canister design with small tubing and multiple sharp bends.

Poor canister fuel level sensor design.

Engine heat soak of VP44 after engine shutdown.



The fuel cooler could be a major factor in not replumbing the return lines. I think you would have to cool the fuel GOING to the VP44 and have a way to take the temperature of it to be sure you accomplished what you are after. I am still a little concerned about the lack of return fuel flow, but if the input fuel is cool enough the lack of fuel flow out of the VP44 might be ok. The VP44 has a fuel temperature sensor in it and I have zero idea about what the computer is going to think about the advance timing circuit with a warm engine and cold fuel, just do not know how that is going to work.



Assumming you do not care about the fuel guage and keep track of miles driven you could not mess with the canister fuel level sensor. This is one of the real bugaboo's. I have never been able to totally seal (it weeps when the tank is overfull from filling from the bed tank) the new fuel level sensor mounting. You could drop the tank every couple of years and replace the fuel level sensor.



A DrawStraw would solve the small tubing multiple bends in the fuel cannister pickup.



You still need to address the after engine shutdown heat soak. I tried wrapping the VP44 in asbestos fabric (used in race cars to keep brake heat confined), and I tried the bilge blower. I checked the VP44 body heat absorption from the engine after shutdown. The asbestos blanket still allowed VP44 heat absorption from the front VP44 mounting, and the rear where the injector lines attach. The bilge blower dumps enough OAT air on the VP44 to counteract the mounting heat absorption, the closeness of the hot engine block, and heat absorption from the injector line rear end. It is also fairly cheap ~ $40 and lst about 2 years and easily replaceable. It also has the added benefit of cooling the TPS pocket if you have not done the microswitch modification to eliminate the TPS. For the bilge blower BE SURE TO READ how Gary figuered out how to keep the blower going after all the electrical system was shoutdown, pretty smart trick.



Bob Weis

 

[Nigel]

JohnBoy

Chip from bluechipdiesel.com was looking for some guys to beta test a system to keep the VP cool. You might try contacting him and see what he has to say. I am not a affiliated with him I just remember seeing a post here a month or so ago.



Nigel

 

[JohnBoy5]

JohnBoy

Chip from bluechipdiesel.com was looking for some guys to beta test a system to keep the VP cool. You might try contacting him and see what he has to say. I am not a affiliated with him I just remember seeing a post here a month or so ago.



Nigel

i am on the list!!!!!

 

[mhenon]

... ... You still need to address the after engine shutdown heat soak... . Bob Weis

Bob, did you read Blue Chips idea on shutdown cooling:

http://www.bluechipdiesel.com/NEW_PRODUCT_ANNOUNCEMEN1.pdf



It's sounds like a similar circuit to Gary's but running the LP instead of a fan. Interesting! I think Chip is right though. The most heat is right after shutdown. I just pop the hood anymore especially on really hot days.

Mike

 

[Hillflyer]

I am coming really late to this party, but a radiant barrier, much like a kevlar glove for working on hot engines would shield the ECM. We use them in construction all the time.
It could be very thin and use stand off bolts to space the ECM from the block heat. Reading your posts you may have already come across this and decided against it. But they can be effective at significant heat reduction. I am all for contributing to a better running and more dependable cummins.

 

[rweis]

Well, better late than never.



Blue Chip's fuel pump idea totally verifies what we found to be the problem with the Vp44. I still run the blige blower mounted under the front bumper. I find the blge pump last about 9 - 12 months then the motor bearings go bad and I replace it.



Blue Chips idea of running the LP is not the best solution I think, because the LP from Dodge is a POS and anyone that still runs the 2nd gen trucks has replaced it with a mechanical pump (I still run the RASP from DTT) or a much better electrical pump. Anyway you are running and puting longer hours on a critical component (LP) that will stop you in your tracks if it fails. The bilge blower is easily replaceable for about $35 (2011 $) as opposed to a high output aftermarket lp or a mechanical pump that is not running unless the engine is running.



Hillflyer's idea of insulating the ECM is a good idea. The same heat soak problem exist with the ECM, just more cycles (longer period of time). I took the ECM off the engine and hung it out in mid air between the engine and the wheel well structure to get it away from the heat. I literally zip tied it to existing wiring harness's and brake line plumbing right in themiddle of the open space between the engine and the wheel well. No more heat soak.

Of course Hillflyer's idea is more elegant and probably a lot more professional looking than mine.



I did try the same idea on the VP44 for a while. I took heat shield used in drag racing to isolate the heat of the brakes and put it between the VP44 and the engine. Not bad and passive vs my bilge blower, but I liked the bilge blower concept for a different reason, above 40 mph the bilge blower (and all my fuel coolers mounted in the fuel line on the way back to the tank) actually overtake the heat generated by the VP44 (even when towing heavy 5er (total 22k)) and start cooling the fuel temperatures below what the fuel temperatures were at say 30 mph.



I have over 100k on it so far and more heat cycles than I can count, and the bilge blower is working perfectly. In the APPS - TPS thread where we disposed of the TPS I did drill 3@ 1/2" holes in the TPS mounting frame and that air flow path helps get the heat after shutdown blower air away from the Vp44. The outside air is never in danger of heating rather than cooling the VP44 chip (at least here in florida).



I still monitor the fuel input temperature to the VP44 and if it starts to go over about 105* I mearly slow down so there are fewer rpm's (pump cycles) that generate less heat. I still find that unloaded the fuel temp is about 10* - 15* above OAT and towing is about 20* - 25* above OAT. Engine rpm (pump cycles) is a MAJOR factor to fuel heating. Towing I think it is running more avanced degree timing in the VP44 and that is what causes more heat towing than empty (Thanks to Gary on that one, I never thought that the difference of towing vs empty would make a difference).



Good luck on controlling the fuel heat for the VP44 and the ECM heat, but you HAVE TO CONTROL THE HEAT, or you will walk someday.



Bob Weis

 

[Hillflyer]

I've been blissfully ignorant of the issues of the 2nd generation cummins. Work is a full time job. I have a 2001 2500 4x4 6 spd mostly stock (4" pipe and better air filter) and 78000 miles. But reading everyone's posts I realized I have just been lucky. I work in construction and all most all of it is locally (within 5-10 miles), with just a few trips out of town over the years on occasion. The Cummins has been bomb proof as a work truck. . or so I thought.

Now that I am getting more miles I see the weak points. All those short, infrequent trips have probably helped kept the heat down on my VP44 and the stock LP is still in it and working smoothly for now. . . shear dumb luck . I am glad I found your group before it left me crying on the side of the road.

 

[kurgan]

I've been blissfully ignorant of the issues of the 2nd generation cummins. Work is a full time job. I have a 2001 2500 4x4 6 spd mostly stock (4" pipe and better air filter) and 78000 miles. But reading everyone's posts I realized I have just been lucky. I work in construction and all most all of it is locally (within 5-10 miles), with just a few trips out of town over the years on occasion. The Cummins has been bomb proof as a work truck. . or so I thought.



Now that I am getting more miles I see the weak points. All those short, infrequent trips have probably helped kept the heat down on my VP44 and the stock LP is still in it and working smoothly for now. . . shear dumb luck . I am glad I found your group before it left me crying on the side of the road.

My 02 went over 100,000 miles and 9 years before having to replace the injector pump. It was still running fine almost all of the time when I decided to replace it. I too had nothing more than a BHAF for all that time. My biggest regret is not installing a fuel pressure gauge on day 2 of owning the truck. I threw the fuel/exhaust/gauge mods in my signature on all at once, and can tell you that once you start modding, it's a slippery slope, but a ton of fun

 

[CM_Guest]

OEMs cool RETURN fuel because that is the RESERVOIR and holds a lot of heat. And it eliminates a lot of potetial leak and GEL points on the supply side.

 

[SnoKing]

CJ, you should be building one of these! Chris

http://helpamericanheroes.com/blog/watch-for-the-johnabilt-in-a-neighborhood-near-you

 

[CM_Guest]

I've got a couple of those. Not with the cab and all, though. I've got a '48 "G" and a '55 "60". The "G" is in a million pieces sitting outside rusting away and the 60 is intact but also stitting outside rotting away. 2-cylinder Deeres used to be my THING and I even did some dealership work on them at the Deere dealer I used to work at. You won't find many JD service technicians my age that even know what a 2-cylinder IS, much less that have any experience with them. But I was into them big-time. I always wanted a "G" and I ended up buying a basket case. I tore it down to nothing and started over, got burned out on the Deere thing altogether and left the dealer scene for a couple of years and even though I came back to working on them, I don't really have the passion for it anymore that I did and I really don't have any interest in those old tractors anymore. I have enough trouble getting motivated to work on my stuff that NEEDS fixed, let alone wrenching for "fun".

There's some old JD wheatland tractors around here with cabs, but you don't see row-crops with them. There are a few aftermarket row-crop cabs around and most of the Wheatland tractors have aftermarket cabs, but to be honest I wouldn't have wanted one back in the day. There's nothing quite like putting a cab on a tractor that was never designed with a cab in mind to end up with something that has ONLY one "advantage" to it. Which is keeping the wind off you when you're working ground in late fall or early spring. Otherwise, they're a PITA and they're loud and vibrate and resonate like a drum and they're hard to get in and out of. But that is a pretty cool set-up. Somebody put some time in it. I can't say it's anything I ever would have done since i like slightly-modified stock, but to each their own.