Fuel tank

[nards444]

Anybody ever check this.  I have a 21 HD Diesel.  I let the fuel get down to the alarm and go fill up at the gas station.  I will only fill up to 29-30 gallons.  I cant imagine when the low fuel goes off it goes off with 6-7 gallons left.  Am I missing something.

[sefton]

My 2014 1500 had 6 gals left when the warning goes on .

My 2001 1500 was about the same .

[Thankful]

2 hours ago, nards444 said:

Anybody ever check this.  I have a 21 HD Diesel.  I let the fuel get down to the alarm and go fill up at the gas station.  I will only fill up to 29-30 gallons.  I cant imagine when the low fuel goes off it goes off with 6-7 gallons left.  Am I missing something.

Diesel fuel foams up so much the nozzle shuts off long before the tank is full.  I can always pump at least 3 or 4 more gallons after the first auto shut off of the nozzle.

[nards444]

7 minutes ago, Thankful said:

Diesel fuel foams up so much the nozzle shuts off long before the tank is full.  I can always pump at least 3 or 4 more gallons after the first auto shut off of the nozzle.

yeah I as thinking that as well.  Ill have to play around some. 

[Random]

47 minutes ago, Thankful said:

Diesel fuel foams up so much the nozzle shuts off long before the tank is full.  I can always pump at least 3 or 4 more gallons after the first auto shut off of the nozzle.

Pretty much this. I typically wait around 30 seconds after the nozzle first tops and then slowly fill up the remainder to reduce foaming. If you are filling up in a commercial truck lane it's even worse with how high flow those nozzles are.

[newdude]

When I had my Colorado Diesel, the light would come on about 2-3 left, and the LOW message when there was less than 2 gallons.  When I would fill, I'd let off pressure on the trigger on the nozzle to slow down the fuel fill speed to let what's already in there start to settle.  I could easily get 19-20 gallons in the 21 gallon tank it had.  

[unit]

Foaming isn't it.  I might get ½ gal more after waiting but that's about it.  Auto makers do it for two reasons: 1 - to keep you from running out of fuel and 2 - to keep from burning out the fuel pump.  The fuel pump is located in the fuel tank.  The fuel cools the pump and If you run too low on fuel there is a good chance you will burn out the pump.  There was no fuel pump on GM Diesels prior to 2017.  The high pressure pump on the engine used vacuum to pull the fuel through to the engine.  An in tank pump was added for the LP5 engines because they are more powerful and require more fuel.  I don't have a problem with the way the gauge reads as long as I know there is X amount of fuel when the gauge reads low.

Edited August 5, 2021 by unit

[Thankful]

1 hour ago, unit said:

Foaming isn't it.  I might get ½ gal more after waiting but that's about it.  Auto makers do it for two reasons: 1 - to keep you from running out of fuel and 2 - to keep from burning out the fuel pump.  The fuel pump is located in the fuel tank.  The fuel cools the pump and If you run too low on fuel there is a good chance you will burn out the pump.  There was no fuel pump on GM Diesels prior to 2017.  The high pressure pump on the engine used vacuum to pull the fuel through to the engine.  An in tank pump was added for the LP5 engines because they are more powerful and require more fuel.  I don't have a problem with the way the gauge reads as long as I know there is X amount of fuel when the gauge reads low.

I always get 3 to 4 gallons after foaming shuts the nozzle off the first time. Always.  It will shut off several times but after the first auto shut off, I keep on delivering fuel until I see the diesel in the tube, always 3 to 4 gallons.

[XY74]

I put 35.4 gallons in mine recently.  The light was on for 30 miles or so.  Odd circumstances, I almost never let it go below 1/4. 

[unit]

Well, that was certainly pushing it to the limit.  Glad to hear you made it to a fuel stop in time.  I carry a 5 gallon jerry can in the bed when traveling just to ensure I can add a little fuel when needed.  I had a similar circumstance three years ago in the Mojave desert and I wasn't at all sure I'd make it to a station that had diesel.  I did make it but it was close!

[Tomato]

The only time I ever had a foaming issue of significance was with B20 biodiesel. I did not want to use it, but that's all the station had.  Too me about 10 minutes to fill the tank.

[nards444]

Yeah was on a long trip this weekend and twice samething and let it sit for a half a min and maybe got half a gallon.  Im thinking the light coming on means there is more than 3 gallons like it seems to be in other vehicles.