E37 2010 Impala E85 Issues

[Slowrc]

I am a fleet mechanic and have to deal with a small fleet of 2010 Impalas that must run E85. They constantly revert back to low alcohol readings and run horrible/ set check engine lights. Has anyone changed the tunes on these pcm's to stay E85 or adjusted parameters that would help these cars keep the high alcohol learn that I tirelessly obtain by draining the tanks and forcing a learn mode refill. THANKS, Rodney

[ScarabEpic22]

Are they tuned now, or all stock? Do they have a virtual or physical FlexFuel sensor? Have you checked the ethanol % using a testing kit?

If virtual, adding an actual sensor might help, however you'd need to tune them all anyway to switch the sensor type (plus populate/calibrate the appropriate tables).

Have a tune file and/or a log when it occurs?

[Slowrc]

Thanks for the reply. I am working on these at work and don't have authorization to put tuning software on them YET. I fight this e85 junk every week because they don't have a sensor and the Gov. employees are mandated to keep the tanks full so they don't enter the learn mode which requires 5 gallons be put in to enter the learn mode. Therefor they constantly lose their sense of alcohol content. We are Obama regulated to burn e85 and it is 90% all the time. I will learn the cars to 70% or so with learn cycle/heavy foot driving and they come back a month later reading 22%. GM tech assist says , " burn regular then..." UGGG

[ScarabEpic22]

Dang, yea even if you didnt want to bother with the physical sensor I wonder if there's a way you could build a small device to just dup the sensor and return an E85% (so around E70 it sounds like) to the ECM so it knows it's always got E85. Unless some employees are putting 87 octane in them...

[Slowrc]

Obummer mandate says corn only or the planet will implode!!!

[Slowrc]

Dang, yea even if you didnt want to bother with the physical sensor I wonder if there's a way you could build a small device to just dup the sensor and return an E85% (so around E70 it sounds like) to the ECM so it knows it's always got E85. Unless some employees are putting 87 octane in them...

That is the concern. With students checking out the fleet for various missions, there is no telling where the next fill up will come from. Surrounding areas don't have e85 either. I have one I am currently working on and when I filled it, it went in the learn mode and although it was showing super lean in the fuel trims, the calculated alcohol content went from 16% to 6%. What a load of crap this algorithm is. I called GM tac line and they said , jus run regular then. Gee thanks!!! I would if we wernt under the green mandate to burn corn!