VP44,, Gauge Question

[MCummings]

Not being scientific or anything,, But I was thinking (Watchout).

We have gauges for EGT, Boost and F. P.



Here's my thought(s)



The VP44 is cooled and lubricated by Diesel fuel.

A healthy original Carter fuel pump pushes 15PSI. I don't remember the GPH but thought it was around 60GPH.



If the '44 returns 60-70% of th fuel back to the tank,, that fuel had to be used to cool the injection pump. If it is used to cool the pump, That means It MUST have gotten warmer, and by monitering the temperature it may be possible to determine the workload and temperature of the VP44.



The gauge should be able to read from about 30-60*F all the way to 200*F. Since the VP44 is right next to the motor and right behind the radiator, and is also working to pump fuel at ~20,00PSI it has to be hot. Especially with the 100*F days that Will soon be here in South Texas.



Would it be possible to put something like a Transmission temperature sender in the return line of the VP44 and moniter the temps? Would this be necessary?

Is the solenoid that controls how much fuel is delivered also cooled by Diesel fuel? If so then you could now when you are pushing the VP44 to it's limits.



This is my personal opinion here, experiance, and thoughts:



My truck is BOMBed,, My Mods rumour me to be at 375RWHP. I tow a 20,000 Pound gooseneck,, and I have BOMBed my transmission (6-speed) Clutch (SBC 13" clutch) Fuel Pump (Dual Fuel Pumps from ADT) and Brakes (Full severe service kit from EGR) to tow this weight.

Right now with my COMP on 3x4 I can be WOT for minutes at a time keeping EGT at ~1450*F max. Now I moniter Fuel Pressure, and EGT,, But what about my VP44?? I don't think it's as cool as a cucumber pumping all that extra fuel Especaillay when the water temerature is at or slightly over 190*F.



Will monitering the VP44 return fuel temperatures give any warning of an overheating, overstressed, or overworked injection Pump?



Anyideas would be appreciated.



Merrick Cummings Jr

 

[KatDiesel]

Just another thought... ... what about a fuel "cooler" ???



What temps are acceptable for the fuel and the VP44... . adding pusher pumps and what not... . what is happening to the temp of the fuel??





Anyone?



We "need" 55 GPH.

 

[JHansen]

Here's even another thought----suppose the reading the fuel temperature sensor inside the VP44 is causing the surge/stumble that some are experiencing-or maybe even affects power? The return line FP temp is a good idea Merrick-I've thought about it myself. Maybe I should make a run or two hard and shoot it with the Raytek infrared thermometer from the plant... .....



J

 

[GMcLean]

The chrysler read out box is able to read fuel inj pump temps, wouldn`t that new roadmaster readout box be able to do the same

 

[KatDiesel]

Originally posted by GMcLean

The chrysler read out box is able to read fuel inj pump temps, wouldn`t that new roadmaster readout box be able to do the same

I don't think it will display the temps. It will display GPH tho.



The problem some people will have is it is required to plug into the data port under the hood that is used by some of the aftermarket fueling boxes.

 

[MCummings]

Wow, Keep the ideas coming guys.



I have to replace the overflow return line from my VP44 in a day or so.

Maybe I'll try to pop in a "T" for a temp. sending unit when I do that.



Any ideas on what gauge I Should use?



Merrick Cummings Jr

 

[KatDiesel]

Something like this... is what I had in mind. No idea if it can be used with diesel, it has -6 an fittings (male)



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But before we get carried away I suppose we need to check and see if the fuel is heated up or not... ... on our trucks.



So I'll be watching you !



I have no idea what range temp gauge to use.

 

[MCummings]

I was diagnosing a return line leak today, and all I can say is, YES! The fuel gets Hot,, as in,, OWW, That's hot. The return line coming out of the VP44 is probably as hot as the valve cover.



My hand tells my brain that the fuel is atleast 120* out of the return line.



I'll try about the temp unit.



Maybe this wil be a future BOMBers gauge. ?



Merrick Cummings Jr

EDIT: Where's illflem? He's measured the temperature of the fuel tank before, and has measured a noticable increase in fuel tank temperatures,, even in cold weather.

 

[yogibear]

Kat, the guys at Edge made me a "Y" hook up to use with my Quickcheck II, the Cummins rep. that was at MM last yr. said it should work using it. I haven't had time to hook it up yet, so don't know.

Larry

 

[Bigsaint]

Merrick, I've been running a temp. sender for fuel temp in my truck for about 5 months now. Mine is hardly in the most ideal location, inbound, right after the Mallory, but it does show that even in the dead of winter the fuel temp rises by about 10-15 degrees above the outside ambient temp. Since it has been somewhat warmer, I typically see a rise of about 20 degrees over the outside temp. after a 20-30 mile ride, a couple degrees less when full over 1/2 a tank I have found very little difference between 1/2 tank of fuel and a full tank, maybe the hotter temps. of summer will show more of a difference.



The best bet would be to tap into the return line with two compression fittings, placing a pressure port fiting in line. The you would only have to plug in a 1/8" NPT sender for the gauge.



Scott W.

 

[HVAC]

Fuel Temps

I've monitored fuel temps and they run around 135*. This is when everything is up to normal operational levels. High temps would be 140*.

 

[Bigsaint]

Might be a good excuse to try one of these



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Scott W.

 

[A Johnson]

From what I remember the engine starts to derate when it sees 160* fuel temp. Now I dont think this is incoming or outgoing fuel neccessarily but is fuel pump temp in general, as I believe the sensor is in the VP44 but I dont know that it actually runs in fuel. All other Cummins engine to my knowledge also use 160* as a max temp spec for fuel. It only makes sense that the BOMBED pumps would generate higher temps. Those of you that have a palm pilot and Quick check or any other reader type boxes should be able to monitor this.

As a side note most marine engines run a fuel cooler in the return from the pump to the tank and it is cooled with sea water, so then if you plumb a cooler in it would be best if it were an air cooled unit as it would make little sense to cool 160* fuel with 190* water. Even if you somehow plumbed it from the cold side of the radiator you only have about a 10* drop across the radiater on a hot day. Just my . 03. AJJ

 

[Bigsaint]

From the standpoint of trying to get more ponies outta the beast, I believe that the cooler pictured above is meant to be placed BEFORE to injection pump. You simply add ice and some water, the fuel is cooled before it ever sees the injection pump. I can't see how it would make much of diiference for most, maybe cool fuel will shave a few 1/10's off the time for the 1/4 mile guys ???



Scott W.

 

[Steve St.Laurent]

I've considered a fuel cooler like that pictured above for at the track for consistencies sake (bracket racing). My concern is what will happen when it's -10 outside, will it cool the fuel too much and cause it to gel? We have a fuel heater in the filter for that very reason.

 

[Joe Mc]

How about a simple tube & fin cooler mounted in front of the rad/condensing coil? Could place a by-pass system in the engine compartment for cold weather ops? Of course it would have to be designed - just an idea

 

[Bigsaint]

Steve, that's a great question I haven't a clue. Guess you could always place heating pad in there for the colder months .



Scott W.

 

[Steve Campbell]

Which is creating the most heat...

the VP44 or the lift pumps. This fuel that is pressurized to 20,000 PSI, does it only see the injection lines or is some of it "nudered" and sent back to the tank with the "cooling fuel". Pressure causes heat. If high pressure on the "lift pump" side is creating extra heat, then the larger the lines and subsequent less pressure "needed" to deliver the fuel to the VP44, should cause a drop in overall fuel temp.



Maybe 90 percent of the heat is from the VP44 and then my thought process has been found out, yet again, to be flawed.



Slightly off the subject... maybe that 6-8 gal of fuel in the tank when my guage says empty was designed into the system to allow a substandard lift pump set up to last a little longer. Also, to provide a reservoir to "cool" some of the hot fuel coming back from the engine.



Speaking of fuel coolers, similar to the charge air cooler for the turbo, they should be mounted as close to the VP44 as possible.