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Looking for some help

ak diesel driver

6.5 driver
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What I need is for someone with a scanner that can read fuel temperature. My hard hot start is back. After driving home I hooked up my Tech2 and my fuel temp was 93*. I turned the engine off and then the key right back on but not to start just the run position then I monitored the temp as the IP heat soaked. It went all the way to 140* before it seemed to stop. Outside temp was about 35*
 

schiker

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There were a few posts on fuel coolers over the years.

This was an old post of mine from the place...... Circa 2008

Clipped.....

I am always interested in more info on this subject. Since that thread I have learned a bit more.....
------------------------------------------------
Jim over on the the diesel page dot com replied to a post of mine "What does the PCM do with the fuel temp info".

Adlibbed he said....

Typical values of fuel temp are 50-194F; DTC 0182 will set if fuel temp sensed over 215F (102C).

Jim doesn't know if that DTC code causes limp mode or any running problem.
------------------------------------------------

I think I have read in my Helm manual that a typical fuel temp value will be 159F.

I believe Stanadyne designed the pump for warmer fuel than older mechanical pumps due to the PMD adding heat to the pump and other reasons (hot location of pump in valley of engine). So some of the stuff you'll see on the internet won't really apply like out dated fuel temp limits of 130-160F.

I suspect the electronic nature of PCM/PMDorFSD and the fuel solenoid the DS IP is better at metering fuel independant of fuel temperature than previous mechanical pumps. But I don't know exactly how whether its program or other. Its a theory at this point because you don't hear of older tired DS pumps having warm start issues like the DB pumps. And why measure fuel temperature if you don't do anything real with the info.

All of the above info is for regular US fuel station pump fuel. Biofuels blends etc ????

END of post circa 2008
 

schiker

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Food for thought......

This is not a common problem on 6.5's that I know of but I just had a friend have to replace injectors in a 5.9 because the injectors were leaky and would bleed down pressure causing hard or no starts at different temps and times.

Wonder if you have an injector or 2 that want to leak down with "thin" fuel plus pumping loss due to "thin" fuel that aggravates each other ????? Mabye both are on marginal issues independently?
 

1999gmc

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So it's 50F ambient right now. I drove the truck about 8 miles. My fuel temp reads 95 with it running. I shut it off and checked temp and it stayed at 95 degrees for about a min. then went to 96. 5 minutes later I checked it and it's 100 degrees. Hope this helps some. Let me know if you need more info
 

ak diesel driver

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Thanks I was wondering if my raptor pump bypassing so much fuel was heating it up , apparently not. It would be interesting to know your temp after 35-40 minutes
 

Will L.

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I don't believe the fuel heater has any function other than fight gelling. I see no need for temps at or above 100f.

My thought was fuel heater stuck on, but I never had to fight them here. Infact more than 1 rig that didn’t have one on it, including ds4 trucks and never an issue.
Does anyone know what controls it? Any parameters to verify?

He is already running thinner winter fuel and if heater is running to hotter temp than needed along with thinned winter fuel- thats how it’s fine the rest of the year and not during winter is my thought.

Any little clues anyone can throw in might help
 

1999gmc

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Thanks I was wondering if my raptor pump bypassing so much fuel was heating it up , apparently not. It would be interesting to know your temp after 35-40 minutes
I'll bring my scanner home this weekend and take a little drive and check it for you. I live 1.6 miles from my shop and when I got here this morning and checked it, it was only at 75 degrees and went up to 77 after about 5 minutes of sitting. So then I took it for a drive of about 7-8 miles. I'm running a Delphi pump with a by-pass regulator to keep fuel pressure at 10 PSI.
 

ak diesel driver

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After I shut it off for the first 5-10 minutes it's starts, after that not so much. If I pop the hood and let it rest on the latch it will usually start. Tried alot of different things including two different IPs and a brand new not rebuilt one ,no difference. I know it's a fuel issue because just the slightest spray of any petroleum product and it will pop right off. I'm sure our extra thin winter fuel doesn't help any either.
 

schiker

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I tried to hook up my "car code computer" and get some other real world numbers but broke my serial to usb adapter. So back to key board info.....

According to alldatadiy.....

Fuel Heater
The fuel heater operates when the temperature of fuel at the inlet of the filter housing is cold enough to possibly cause waxing that could restrict flow to the injection pump. A control circuit inside the fuel heater completes the circuit for the heater element when it senses a temperature below 8°C (46°F).

+++++
As long as your fuel is winter fuel....
Might could unplug the fuel heater to see if that makes a difference if its heating the fuel up too warm and its thinning.

Or might could open water drain and pump out any warm fuel and cool the in the fuel manager if you can operate your lift pump then see if it starts.
 

Attachments

Twisted Steel Performance

Anything worth doing is worth overdoing.
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I wonder if your fan system is not pulling much if any air through during idle causing a bit more heat to just sit and soak before shut down ?

Next time if you can manualy turn the fan on do it a mile or two and while you are parking, see what the temp shows after a brief fan run...
 

Will L.

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Unplug the fuel heater. Test drive it and try to recreate the issue without it. I am convinced the heater sensor is not reading right and has the heater on when it should have shut off.

To verify, you really need to start the truck and then unplug it. Then drive it getting truck up to full temp, working truck hard preferably. Then see if fuel temp shoots up again, and if hard start reoccurs.

I get that freezing temps outside a fuel heater helps, but i think itnis cold enough to turn on the heater, and the sensor is faulty. So when the fuel is hot enough it should shut off- it doesn’t.
 

FellowTraveler

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I am kinda wondering if my coated radiator is giving off more heat while turned off. I'm leaning towards underhood temps being higher than stock coupled with the winter fuel.
What is the radiator coated with?
As you know air density plays a role in fueling "if I remember right" via IAT sensor perhaps increasing boost will help.
 
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