GM Volt Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
33 Posts
Discussion Starter #1
Seem to be having a problem with fuel maintenance mode kicking in to often in our 2016 Gen2 Volt.

First tank from the dealer lasted us from Feb '16 to Jan '17 when fuel maintenance mode kicked in.

Burned the tank down to about 1/4 and put in 6.22 gallons to reset the fuel maintenance.

Less than a week later fuel maintenance kicked in again.

Let it get down close to 1/4 tank again and 15 days after the last tank of gas put in another 5.61 gallons to top it off.

Now we are just over a month later and it's in fuel maintenance mode again with nearly a fuel tank of gas.

Given we put in over 11 gallons of new gas in the last half of January I wouldn't expect fuel maintenance mode to kick in for 6+ months minimum.

Does this sound messed up to anyone else?
 

·
Registered
Joined
·
1,120 Posts
That does seem a bit excessive. I know FMM is supposed to run until a sufficient amount of old fuel has been burned. Perhaps filling at 1/4 tank keeps the car thinking that the ratio of new/old fuel isn't sufficient. If it runs again, perhaps run until you get a low fuel warning before filling. If it occurs again then it might be a trip to the dealer to diagnose.
 

·
Registered
Joined
·
907 Posts
Are you sure it's running FMM and not EMM? I typically run around on 1/4 tank. And have never had FMM come on, yet(!) (gen 1)
 

·
Registered
Joined
·
1,120 Posts
Based on the OP's description of February of last year until January of this year it would make sense that it is FMM trying to complete the cycle. EMM usually lasts a few minutes and runs every 6 weeks or so where FMM will actually run until it burns enough of the old fuel out that a fill up will be primarily fresh gas. This is supposed to run roughly once a year if old fuel is present. If the OP hasn't used any fuel in that period or minimal due to EMM it would stand to reason that the computer is trying to burn enough fuel until the condition is satisfied. My thought is that by filling up at 1/4 tank might not be sufficient for the system to recognize the old fuel has been burned since its been mixed with fresh and suggesting they wait until a low fuel indicator before filling.
 

·
Registered
Joined
·
1,639 Posts
Your first FMM sounded like it was correctly timed. The FMM occurs when the "average age" of the gas in the tank is ~12 months old. If you then burned gas until the volume dropped to ~2 gallons and added just 2 gallons of new gas, the "average age" of the 4 gallons will be 6 months, and you should have 6 months until the next FMM. You added even more than 2 gallons.

However... when the FMM message appeared, did you say Yes to the question, rather than postponing the start? Or did you punch the Postpone option and then switch to Hold to use gas, or did you just drive to the gas station and add more?

You need to Start the FMM before it can be Ended. I’ve read of someone who got the FMM message and postponed it. He had only a small amount of gas remaining in the tank, so he then filled the tank, thinking he was adding plenty of new gas and avoiding FMM completely. The next day the FMM message appeared again, suggesting that the computer sets a flag when the "average age of the gas" is determined to be 12 months, and doesn’t check it again until after you say Yes, Start the FMM. When you add gas after starting the FMM, the age test is again computed to determine the timing of the next FMM, and the FMM is completed and turned off.

If you did say Yes to start the FMM and are still having this problem, or if you didn’t and now have the problem and nearly a full tank of gas, you could check with the dealer. I think I read in a thread within the past six months of someone who had a similar problem that was corrected when the service department was able to reset the FMM clock, so to speak.
 

·
Registered
Joined
·
949 Posts
I went through mine last October, got the "engine not available" and "propulsion power reduced" messages, still had 90% full HVB as it had been not been used due to FMM -- was only a miles from the gas station (as planned) and got a little bit of gas and the ICE hasn't come on since October, except for EMM every 6 weeks of course.

 

·
Registered
Joined
·
872 Posts
Wow 54.6 mpg on the gas engine for 380 miles. What type of driving were you doing?
That's what I want to know! I've gotten 64 miles electric before, but I've never gotten my average MPG above 45.
 

·
Registered
Joined
·
949 Posts
Wow 54.6 mpg on the gas engine for 380 miles. What type of driving were you doing?
Just the normal commute back and forth to work, is 54 miles each way (would plug in near work when *not* in FMM)... note that while FMM runs the ICE to burn the fuel it does use the HVB slightly as well (used 2.4kWh) so that boosted the overall MPG up a bit, so it wasn't all gas.
 

·
Registered
Joined
·
33 Posts
Discussion Starter #10
Thanks, yes, I made sure that we allowed the FMM to be in process before filling up.

Sounds like it will be a call/trip to the dealer again. Was just there last week doing the first of the free oil changes at the 1 year mark.
 
1 - 10 of 10 Posts
Top