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For the first time my quadzilla was pegging my fuel temp over 160 and crept to 163  I was getting back to work so the truck is off.  Is there any thing I can do about this?  What could be the source?  I haven't had gauges before now so who knows if this has happened before.  Thoughts and ideas?  Thanks!

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I think I read somewhere several years ago, that above 140deg, asphaltene begins falling out of the fuel, creating a black gooey mess. There was a long thread on TDR where guys were trying different means of keeping the fuel cooler. Including log style fuel coolers. I don't remember the results.  Someone measured the fuel return temp to the tank. It was quite hot. Probably the easiest thing to do in the hot months is keep the tank on the full side.

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3 hours ago, greed said:

Probably the easiest thing to do in the hot months is keep the tank on the full side.

That's a good advice, I've noticed temp rising as tank gets lower. Another thing is I have a modified fuel basket where my in and out are in the same basket but all in 1/2" so yes as tank gets empty heat goes up. Now if you did your draw straw the right way like @Mopar1973Man did and don't have 1/4 tank air suckling issues then it's more beneficial to return to filler neck to help keep heat down so you don't recycle it as much and it keeps 2-cycle mixed better but I'm just guessing here. I never had a problem with my basket but whoever installed my draw straw cut it way to short. And I generally fill up around 1/3 of the tank if I can for several reasons. 

I've seen my fuel temp around 150 and usually when I get low on fuel, usually it's around 130ish

 

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I'll give that a try.  I am just under 1/2 tank so I'll filler up and see if there's a difference and let yall know. 

 

I do notice at idle it rises, but when moving it drops to the 150's so it's cooling and hasn't gone above 163*.  Still seems high though. 

 

I have the stock tubing from the tank into the 150 Raptor pump but 1/2" from the pump to the filter to the vp44. No problems with pressure. I even deleted the fuel heater (not sure if that was on all the time or just at a certain temp.. Anyway I'll see how it acts tomorrow.

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Posted (edited)
8 hours ago, SavageTusk said:

even deleted the fuel heater (not sure if that was on all the time or just at a certain temp.

 

Only if the temperature is below 70*F. Then it switches off above 70*F. 

 

With all my driving back and forth, I can say without a doubt IAT and fuel temp typically are within 5 degrees of each other. 

Edited by Mopar1973Man
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As one who runs his tank until low fuel light comes on and beyond sometimes, I have never noticed any difference in how the truck performs with a full tank or near empty tank. Winter/summer or towing/empty. All my return fuel goes to the fuel basket. Maybe one day if I swap to a quad I will see what the fuel temp is. The only fuel related issues I have ever had involved hard parts and not the fuel itself.

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Well I filled up and it hasn't gone above 132 yet.  It does seem intake air temp is warmer than I'd expect, especially with a cold air intake.  Maybe I need to clean and re-lube my air filter this weekend.  Here is my datalog if yall have any input; this is after an hour drive.

 

 

fueltemp071318.PNG

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Posted (edited)

Dripley, is that the chicken flavored? Yumm!

 

Washable filters, even with the best of care start breaking down with each washing. At least that's the word on the street.

Edited by JAG1
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30 minutes ago, JAG1 said:

Dripley, is that the chicken flavored? Yumm!

Butter!!

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On 7/11/2018 at 4:31 PM, greed said:

I think I read somewhere several years ago, that above 140deg, asphaltene begins falling out of the fuel, creating a black gooey mess. There was a long thread on TDR where guys were trying different means of keeping the fuel cooler. Including log style fuel coolers. I don't remember the results.  Someone measured the fuel return temp to the tank. It was quite hot. Probably the easiest thing to do in the hot months is keep the tank on the full side.

 

This.....  Diesel fuel asphaltene is no joke.  Many people mistake "algae" in their fuel tank but that black crud is commonly ashpaltene from hot fuel over 140*.  Its even been discovered that lower sulfur in diesel can cause instability issues too, and combined with high heat running fuel system conditions, ashpaltene particles can form.  The stuff will also plug up a fuel filter too.  I think there's a good reason the VP has a fuel temperature sensor which triggers at 160*.

 

I remember having this discussion a few times on the forums years ago too but it was eventually a general consensus that this must not be an issue for these trucks since non came with a fuel cooler.  Still not sure about that but nonetheless, its best to keep the fuel tank no lower than 1/2 tank in the hot weather due to the constant re-circulation of the fuel.  And to aggravate the issue, the fuel module pulls inlet fuel right next to the return outlet which means unless you have a draw straw or sump your fuel in the lines could have been running round and round getting hotter and hotter.  You can only imagine how hot a small amount of fuel in the tank will eventually reach.

 

In saying all that, there's plenty of diesel applications which run fuel coolers.  Even Mercedes has a diesel (not sure which one) which runs a fuel cooler integrated into the AC low pressure line.  Pretty slick way to address a hot weather fuel condition.  Lots of other people run fuel coolers on their diesel trucks but given how susceptible these particular trucks are to fuel leaks and starting issues, some people looked at it in that adding a cooler would only add more places to leak.

 

I eventually gave up on the idea and to this day I will not run any lower than 1/2 tank in the summer and 1/4 in the winter.

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Posted (edited)

Did someone say fuel cooler? Here's some old info,

It's getting hot here so I went to a local boneyard and purchased a

trans cooler for $10 and installed it so that when the motor is

running, air is being pulled past this cooler.
I bought a cooler install kit, hose & clamps at the auto parts

store.

Image004.jpg.18693bc4a24479f27872ad8d9eb4e194.jpg

I trimmed all the existing mounting brackets off the cooler since

they didn't fit anything on the truck.

There is a stud and a place for screwing in a bolt like maybe a

factory extra heavy duty trans cooler in the same area.

I cut the return line just where it gets to the frame rail and

added enough fuel hose to get to the front of the truck. Ran the

hose across the frame, behind the brake lines and over the inner

fender to the front.

Image011.jpg.f378ab97fe48ba2381bb825278972ceb.jpg

Image016.jpg.85afa6e5fb9814ff1122213c606d2bdf.jpg

Image018.jpg.918796a816776f9555516483b300ede0.jpg

Image021.jpg.ffd2bf47197c3bae33941d4d14342bb9.jpg
After I finished the job and 1 hr. test ride and it does work but

not as good as I'd hoped. The fuel gets cooled to ambient sure

enough and the fuel tank is cool but there's still a bunch of heat

soak from the motor I guess. I can now hold my hand on the VP top

until I get bored but it's still very warm.
The good part is even if I get stopped in traffic, the fuel will be

cooled as long as the motor is running.
Just for general knowledge, I timed the flow of the return

line....a little over 3 qts./2 min. @ idle and 2qt./min. @ 1600 rpm

stationary....lift pump showed 15 psi.

 

Oh, it's still on the truck after many years.

Heat soak is still an issue so I raise the hood after I get home on hot days.

Edited by Clunk
Update
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1 hour ago, Clunk said:

Oh, it's still on the truck after many years

I would be getting a better higher flow fuel pump if it was me, then it be much better, jmo.

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3 hours ago, Clunk said:

Oh, it's still on the truck after many years.

Heat soak is still an issue so I raise the hood after I get home on hot days.

 

Nice setup.  I got into the habit of raising the hood too...  Not sure it does anything other than give me peice of mind knowing that the PSG isnt being heat soaked as much.

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My typically hot fuel mark is 130-135*F on 107* day. Even after parking for long periods still very little rise. Typically my IAT and Fuel temp are nearly the same. Typically flip-flopping IAT and fuel temp at about +5*F spread. Maybe that why I can go 60k miles with fuel filters because I'm not creating any asphaltene.

 

Last two years now I've got 250 mile round trips between Ontario, OR and home. Last trip I measured the outside air at 107*F and the fuel temp maxed out at 135*F. IAT was floating about 132*F. BHAF as well. Remember its not the cold air intake. It about the temperature crossing the intercooler. Then there is a coolant jacket within an inch or so from IAT sensor.

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Posted (edited)
21 hours ago, Dieselfuture said:

I would be getting a better higher flow fuel pump if it was me, then it be much better, jmo.

Thanks, my pump is rated 140gph.

 

Wow, I need to update my signature.

Edited by Clunk

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My problem isn't really the summer heat even though we reach the 100's every summer. My problem is the winter time keeping the fuel from gelling up in -40*F weather. This is the only reason I've never bother with a cooler for the fuel. Like others have mentioned I'm not returning to fuel basket I've got it to the filler neck. My fuel lines do not run outside the frame but inside the frame so it shielded from extreme cold and extreme heat. I'm also using an old-school draw straw from the early AirDog 150 time still never failed and still no 1/4 tank issues for a daily driver. Still I'm changing fuel filter every 60k miles because they never get dirty. 

 

60k miles and no pressure loss.

Image result for mopar1973man airdog fuel filter

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I have never had to worry gelling for the most part, just not in that cold of climate 90% of the time. I have seen near 0 temps with no problems for some trips. I have wondered about the fuel temps with both return lines going to the fuel basket and the fact I have always run my tank low on road trips both winter and  summer. Just never have had filters clog  prematurely or any other side effects that i know of.

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22 hours ago, Dieselfuture said:

I would be getting a better higher flow fuel pump if it was me, then it be much better, jmo.

 

Any aftermarket fuel pump will push more than enough fuel since the whole premise behind fuel lubricating and cooling the VP is having more fuel pass through it than the engine needs.  The limiting factors will always be what fuel volume can pass through the VP at any given time.  Even the air separation fuel pump systems which have their own return still offer no additional benefit to fuel volume through the cooler since their return fuel is dumped directly into the fuel tank inlet.

 

A thermo bypass, built in thermostatically controlled, heat exchanger would probable by ideal in one of these situations.

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Posted (edited)

Return from the VP44 is very limited anyway... Return on the left and supply on the right. No matter what you do for pressure the volume is limited to that small port drilled in the body of the pump. This why I never suggest pressure beyond the standard 14-20 PSI. There is nothing gained going to higher supply pressures. 

 

Image result for mopar1973man vp44 return port

Edited by Mopar1973Man
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2 hours ago, Mopar1973Man said:

Return from the VP44 is very limited anyway... Return on the left and supply on the right. No matter what you do for pressure the volume is limited to that small port drilled in the body of the pump. This why I never suggest pressure beyond the standard 14-20 PSI. There is nothing gained going to higher supply pressures.

 

Correct, except that the VP return is only part of what volume makes its way to the fuel tank.  The rest is excess fuel at the injectors.  And thats actually the HOTTEST fuel as its flowing out the back of a 200*+ cylinder head.

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