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Hello, I am having the, what I think, is a common problem for the LMM Duramax which is the fuel level sending unit where it says I am empty when I still have like 11 gallons left. Does anybody have a part # for this? I am seeing there are $450 or you can get just the little rod which is $60… please save me a headache
 

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One thing to consider is that, unlike a gasoline engine that does not use a residual supply of fuel in the tank to temper the temperature of the fuel returned from the injectors, a diesel truck needs cooler fuel in the tank to keep the temps down. Diesel fuel is used to cool the injectors and excess fuel is returned to the tank thru a fuel cooler. There are problems with hot diesel fuel, sometimes in the 200* area, that would be unmanageable without that residual supply. A very small tank reserve would not provide the temperature buffer needed to reduce fuel temps. CP3 pumps have a more difficult time with hot fuel in attaining and keeping the actual pressure following the desired pressure and that sometimes results in P0087. One question to consider is do you really need 11 gallons? And is that really what you have remaining? Our trucks are fitted with tanks of different sizes, 26, 34,50, at least for the 2008 models. I believe that I have put in 27 gallons on a very cool night in my 34 gallon tank, so I think the intended reserve is likely about 7 gallons.

Just don't want you to think you can get down to a gallon before your gauge says empty. That might work OK in cold weather, not so much in summer in Death Valley.
 

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2007 GMC Sierra LBZ
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Here is the GM # for the level sensor SK1348. This is the number for the tank module without the level sensor 19206540. As to Ron’s comment the short beds have a 26 gallon tank long beds have a 34 gallon tank only the cab and chassis would have 50 since they have double tanks. I put a new module and level sensor in my LBZ and now once light comes on i can get 21 gallons in and since i have a bottom sump installed i can go longer after light is on and have already put in 24 gallons. I also have half inch hose running directly from AirDog to CP3 and 3/8“ hose as return directly to tank. No longer have a cooler.
 

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These trucks, especially the ones with the 26 gallon tank always read low. My 08 will have the low fuel warning and the tank ready empty with the DIC showing only using 20 gallons. Best investment I made was installing a S and B 62 gallon tank in my truck. Worth every penny especially if you pull a trailer often. Dean
 
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