Dual tank fill-up to top
Hello all. I am 7,000 miles into owning a brand new '21 Chevy crew cab, cab chassis 4x4 DRW gas truck that came with dual fuel tanks (40 + 23.5 gal). In the whole ownership of the truck, I have ...
Forum Discussion
Hopefully you’re still under some sort of warranty from the up fitter if it’s not a GM issue.
Waiting 3 years to address it may leave you holding the bag if it’s an upfitter issue or past the 3 year mfg bumper to bumper.
I’m guessing not many, if any, here, have that setup as it is only offered with C&C gassers I believe. Which are relatively rare to start with.
If it’s not simply an error in mounting the fuel fillers, then idk.
According to the OM it says if you run out of gas fill the front tank first, so I’d surmise that the engine always pulls off the front tank and the rear pump is a transfer pump triggered by level sensors to either keep the front tank full until the rear tank is exhausted or to trigger the transfer pump periodically to re-fill the front tank partially (since the rear tank is bigger).
You say sometimes it works but realistically you’ve filled them less 10x or less based on the miles.
Do you have any data to help you figure out that sequence and also how low in which tank you were when refilling? You could theoretically use 40 gallons of gas and the front tank still be plum full.
And yes of course you can fill the front tank (if it needs gas). But depending how the truck calculates total fuel/miles left, you could be around “1/4 tank” on the gauge and be at 3/4 full or more in the little front tank.
Since you’ve procrastinated 3 years, now is the time to maybe learn how the fuel transfers to eliminate user error or ignorance from the equation to pin point an actual issue if any.
Easy test, run that sucker almost empty until you know you’ve pulled a bunch from the front tank and then see what happens when you fill up.
I presume the dual tank models only have one gas gauge and the mpg and dte info takes both tanks into account?
Both my newer chebbys in the last few years have been spot on with dte and fuel gauge readings (leaving about 2 gal in the tank when dte miles goes to zero and actual tank capacity at rated cap when the truck runs out of gas (once, lol)). I’d think yours is also reliable. I’d suspect your low fuel light should come somewhere between 5-10 gal left in front tank or total in the system.
Waiting 3 years to address it may leave you holding the bag if it’s an upfitter issue or past the 3 year mfg bumper to bumper.
I’m guessing not many, if any, here, have that setup as it is only offered with C&C gassers I believe. Which are relatively rare to start with.
If it’s not simply an error in mounting the fuel fillers, then idk.
According to the OM it says if you run out of gas fill the front tank first, so I’d surmise that the engine always pulls off the front tank and the rear pump is a transfer pump triggered by level sensors to either keep the front tank full until the rear tank is exhausted or to trigger the transfer pump periodically to re-fill the front tank partially (since the rear tank is bigger).
You say sometimes it works but realistically you’ve filled them less 10x or less based on the miles.
Do you have any data to help you figure out that sequence and also how low in which tank you were when refilling? You could theoretically use 40 gallons of gas and the front tank still be plum full.
And yes of course you can fill the front tank (if it needs gas). But depending how the truck calculates total fuel/miles left, you could be around “1/4 tank” on the gauge and be at 3/4 full or more in the little front tank.
Since you’ve procrastinated 3 years, now is the time to maybe learn how the fuel transfers to eliminate user error or ignorance from the equation to pin point an actual issue if any.
Easy test, run that sucker almost empty until you know you’ve pulled a bunch from the front tank and then see what happens when you fill up.
I presume the dual tank models only have one gas gauge and the mpg and dte info takes both tanks into account?
Both my newer chebbys in the last few years have been spot on with dte and fuel gauge readings (leaving about 2 gal in the tank when dte miles goes to zero and actual tank capacity at rated cap when the truck runs out of gas (once, lol)). I’d think yours is also reliable. I’d suspect your low fuel light should come somewhere between 5-10 gal left in front tank or total in the system.
