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5+ years, 3 Volt's and 1st FMM - Rat's

3134 Views 33 Replies 14 Participants Last post by  llninja
I knew it was lurking, bought our 2017 Aug 20th 2016. Have driven over 7400 miles and only have 50 miles on the ICE. VoltStats reports I'm operating my Volt at 99.3% all electric. My other two Volt's (2012 and 2013 driven over 45K miles) but they never needed a FMM. So today I get the FMM message and accept it. I have about 5 gallon's of gas in the tank. So I have one question and one observation.

Question: How much fuel will be burned off, all 5 gallons, a percentage, how much?

Observation: I know the door label shows my car was built 06/16, but since the FMM chose today to run, can I assume my car was "built" or given birth on June 22nd 2016, 365 days ago? I say that because there must be a clock/calendar built into the car and someone had to write the code to make this work and it makes sense to say "365 days from TODAY start FMM on the day the car registered fuel being added". Thoughts/comments.
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Question: How much fuel will be burned off, all 5 gallons, a percentage, how much?
Once FMM starts the Volt will start to burn all of the fuel in the tank, i.e. 5 gallons. You can reduce the amount of fuel that will be consumed by FMM right now by mixing fresh fuel with the old fuel. The Volt will compute the average age of the fuel ((age of old fuel * gallons of old fuel in tank) + (age of fresh fuel * amount of fresh fuel added))/2.

It all depends on how much gas you are comfortable having sit in the fuel tank. If you allow FMM to use up 2.5 gallons of old fuel, starting now, and then purchase 2.5 gallons of fresh fuel, FMM will be suspended with 5 gallons of a mixture of 50% old fuel and 50% fresh fuel in the tank. In six months the Volt will ask you to allow FMM to run again.

You could suspend FMM right now by filling the fuel tank with 4 - 5 gallons of fresh fuel but then you would be carrying a full tank of fuel in the Volt when you regularly need to use only minimal amounts of gas. In this case too, in six months, the Volt will ask you to allow FMM to run again.

Since you normally use so little gas you may want to allow FMM to burn up all of the fuel in the tank (get the amount of old fuel in the tank down to less than 1/3 or 1/4 gallon) and then add 1.5 gallons of fresh fuel. That amount of fuel should last about a year with Engine Maintenance Mode running for about 10-15 minutes once every 6 weeks. Then, a year from now, you would purchase another 1.5 gallons of fresh fuel.

I keep my Volt's fuel tank between 1/3 and 1/2 full because I like knowing I have 125 - 200 miles of ICE range. I don't wait for EMM to run once every six weeks. I use Hold mode and run the ICE engine for about 8 - 10 miles every two weeks to circulate the fluids and and to fully heat up the engine oil to 190 F + to drive out any moisture from the engine.
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Thanks for the detailed info. My plan is to EMPTY the tank and then add 2.5 gallons of fuel. And that will hold me until this winter and start using fuel for ERDTT duties.
Just don't run the fuel tank completely dry. The Volt needs at least a small amount of fuel in the fuel tank else it will switch to reduced propulsion mode. Instead of emptying the tank now why not just get down to 1 gallon of old fuel and then add 1.5 gallons of fresh fuel. The mix would be 33% old fuel and 66% fresh fuel, that should keep FMM from running for 8 months. That should last you until sometime next winter when you stated you will add some fuel for Engine Assist Heat.
You can decline once, the next time you start the Volt the FMM will run until either the fuel in the tank is used up or until you add sufficient gas to the tank to extend the average age of the fuel for a while. Adding a small amount of gas to the tank will not delay or extend the FMM program from running, it has to be significant amount to affect the total volume of fuel in the tank
Sorry to be picky, but you would need to add 2 gallons of fresh fuel to 1 gallon of old fuel to end up with a 33% to 66% mixture.
I'm glad that somebody is paying attention. That mix would be 40% old gas and 60% new gas.
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