Fuel temp too low???

Duranali

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Jun 8, 2014
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I've had my 2013 duramax for several months and just put an edge tuner on. I'm not sure what kind of power to expect since this is my first diesel, but I've always thought that the truck ran sluggish as if it never really warmed up. I happened to run across the fuel temp gauge on my tuner and it says that the fuel temp is 32 F and it's 90 outside. Could this cause performance issues?
 

Matt750

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Apr 29, 2012
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Just a thought, are you sure it is reading F not C? Because 32C is equivalent to 89.6F. I am not sure about yours, but in the tuning for my LBZ I believe I saw a table related to fuel temp. I am an EFI user and have admittedly never had my hands on an edge, but maybe check to see if there is any way to check if it is set to C or F in the tuner.
 

Duranali

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Jun 8, 2014
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Nope. It clearly says 32F and never changes. I'm wondering how the ECM varies fuel timing and delivery based on this parameter?
 

x MadMAX DIESEL

<<<< No Horsepower
Dec 30, 2008
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There is most defiantly tables that limit/change fueling based on fuel temp. If you unplug it does it change? Bet you need have a back sensor
 

Duranali

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Jun 8, 2014
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That's my next move when I get a spare minute. Can you jump the the sensor wires together and cause the gauge to read either full cold or full hot? This would be my test to see if the ECM is working properly.


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NC-smokinlmm

<<<Future tuna killer
May 29, 2011
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Coud be a bent or unseated pin in the edge bale connectors if your edge has them? Causing low reference voltage. Remove the edge and see what it is doing with a scanner or tech II...
 

Duranali

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Jun 8, 2014
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Well, I'm trying to test the sensor, but I can't figure out where it is. Anybody got a picture that can help?


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Duranali

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Jun 8, 2014
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If it were mine it would be at the dealer, that's what warranty is for buddy...:hug:
It's going to the dealer, but I would like to simply unplug the sensor to see if there is a change in the reading. That way I have a better idea of what the problem is. I don't have a lot of faith in warranty mechanics.
 

Duranali

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Jun 8, 2014
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Still haven't found the fuel temp sensor but I've got a problem that may be related. It doesn't happen every time, but I am lose fuel rail pressure under full throttle. If I continue to hold the throttle, the pressure comes back and it accelerates again. It's never done it running the stock tune, but maybe I need to change the fuel filter? The truck is only a few months old though.


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kidturbo

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Jul 21, 2010
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What pressure do you see it hit before it falls off?

There is a fuel pressure bypass valve in the back of the drivers side fuel rail that will pop open if you exceed it's rated spring pressure. Being it's fine in stock tune, betting that's it. Block off unit cost like $35 at PPE. Fuel filters typically don't recover if you hold the throttle open...

The fuel temp sensor is on the drivers side near the rear of the engine between the valve cover and fuel rail. Located in the smaller fuel return line, near where the plastic lines from the injectors connected to it.

Hope that helps
 

Duranali

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Jun 8, 2014
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The pressure gets to around 24k and then drops to 4. Thanks for the info on the temp sensor. I'll give that area another look.

BTW, after it does it once, it seems to fine, meaning it doesn't lose pressure under full throttle again until the next time I run the truck.

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