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E85 now check engine light

9K views 49 replies 24 participants last post by  deezomaxima 
#1 ·
i have an 09 gt and i put E85 in my car for the first time last night and before i could get home my egine light came on. My light will come on because the gas cap but checked it and it is ok. Can our cars run on E85 ok? Also I tried remote starting my car and it will not work now. what do you think?
 
#4 ·
Yup, stock the car isn't set up to run E85. The fuel lines and such are ok with it but the G8 lacks the programming to run it.

Also remote start is disabled any time you have a check engine light.
 
#6 ·
I wouldn't. You need an ethanol sensor that our cars lack to run e85. Plus the tune doesn't support it stock. You could damage the engine running it lacking these things.
 
#8 · (Edited)
I wouldn't be driving it at all with that in the tank. It's gotta be running dangerously lean and risking engine damage especially at WOT. Ethanol burns at a different air/fuel ratio and requires roughly 30% more fuel to burn at stoich compared to gasoline. This can be corrected with the proper tune, but otherwise get that stuff out of your tank! As stated, flex fuel cars have an alcohol sensor that determines the ethanol content and adjusts the air/fuel ratio accordingly. I'm willing to bet your check engine light is because it's running lean and your fuel trims are way out of whack.
 
#9 ·
I wouldn't be driving it at all with that in the tank. It's gotta be running dangerously lean and risking engine damage. Ethanol burns at a different air/fuel ratio and requires roughly 30% more fuel to burn at stoich. This can be corrected with the proper tune, but otherwise get that stuff out of your tank! As stated, flex fuel cars have an alcohol sensor that determines the ethanol content and adjusts the air/fuel ratio accordingly. I'm willing to bet your check engine light is because it's running lean and your fuel trims are way out of whack.
This. I run E85 but i have a tune for it.

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#10 ·
if you don't want to pump out the E85 start pumping in the highest octane you can get, and find some NOS octane booster (i think it brings up the octane level 5 real points so 93 becomes 98) and it might help you out.
 
#13 ·
Dropping the tank can be a big pain in the butt (so I've heard). If you were thinking about getting a tune anytime you might just wanna go that route and enjoy the extra horsepower.

Yes your car does probably feel a little faster right now because lean conditions usually make a little more power.....right before it goes boom!
 
#15 ·
Dropping the tank can be a big pain in the butt (so I've heard).
Actually, I experienced this a week after owning the car.

The entire exhaust system needs to get dropped.
The entire rear cradle needs to be removed
then tank comes out from the bottom.

Definitely an involved task if you ask me.

Mine was the cause of a malfunctioning rollover valve, my tank replaced under warrantee.

I only run 93 top tier octane. I hope your engine is not getting damaged!
 
#14 ·
Flush system?

What are your fuel trims, and AFR? I wouldn't risk damaging the engine without proper flex-fuel tooling of the car and a corresponding tune for the engine.

There are those who DO run E85, but they're pushing big power already.

Your car stock op?
 
#18 ·
Would I benefit from running E85 with my bolt ons and a new tune to work with the E85. If there are gains to be had Im just an email and a tank of fuel away form picking up some more power.
 
#16 ·
Wow, did I really just read this!
 
#50 ·
+1

I can't believe the OP didn't research this first. Better just be easy with it until it runs out if you need to drive the car as a DD or just siphon out what you can.
 
#17 ·
New Caprice PPV's have the L77 engine which is similar to the G8 GT's L76 powerplant except it is also flex fuel certified.

Might benefit you to start to research the differences in the fueling system and other bits from the PPV if you want to learn more about running Flex Fuel in your GT, OP.

Hopefully this is not a troll. Like the "I put sand in my intake to port it" golden interwebs thread from yesteryear.
 
#21 ·
How much E85 did you pump ? Lol
the DTC light is ON because the fuel trims are way higher than 25% towards the lean side, and the computer is no longer able to control your AFR mix to 14.68 when in part throttle, your WOT is also adding fuel probably up to 25% to compensate, you have to let the moonshine burn in full, and don't try this again unless you get a tune for it.

Look at the positive, you're cleaning out your fuel system :), please don't give her gas to enjoy the power, avoid WOT runs, it won't be good for your engine, just let it go to empty and pump your regular fuel.
 
#27 ·
How much E85 did you pump ? Lol
the DTC light is ON because the fuel trims are way higher than 25% towards the lean side, and the computer is no longer able to control your AFR mix to 14.68 when in part throttle, your WOT is also adding fuel probably up to 25% to compensate, you have to let the moonshine burn in full, and don't try this again unless you get a tune for it.

Look at the positive, you're cleaning out your fuel system :), please don't give her gas to enjoy the power, avoid WOT runs, it won't be good for your engine, just let it go to empty and pump your regular fuel.
Well great on not adding fuel! What will this do? You would think this would be the best thing to do so the computer could keep things closer to normal. Not to mention these fuels would have to be able to work together for normal flex fuel cars. So running the car to empty would seem like the worst thing to do instead of adding reagular fuel. The ligh off seems like a good thing at least, right?
 
#22 ·
Thank you BlueGoat06 for your expertise in this. I was hoping you would chime in... and I was not disappointed.

Notice on the pumps where you pumped in your E85, it should have a warning of "Warning: Only safe for flex fuel capable automotive applications" or something to that degree.
 
#23 ·
REALLY?? Where on the G8 or in the manual did you see a sticker, tag, emblem, or otherwise stating that it was a flex-fuel vehicle. If not, why would you even try this??

Some good information in the other replies though. Just drive EASY, and run it out, then go back to regular gas. Fortunately, E85 doesn't produce as good of gas mileage, so it shouldn't take you long to run it out.

I'm not sure you would see a whole lot of gain from an E85 tune on a bolt-on car (maybe 15hp), but it does run cooler and keep the fuel system cleaner. Where you really see the gains are on a forced induction car.
 
#25 ·
REALLY?? Where on the G8 or in the manual did you see a sticker, tag, emblem, or otherwise stating that it was a flex-fuel vehicle. If not, why would you even try this??

Some good information in the other replies though. Just drive EASY, and run it out, then go back to regular gas. Fortunately, E85 doesn't produce as good of gas mileage, so it shouldn't take you long to run it out.

I'm not sure you would see a whole lot of gain from an E85 tune on a bolt-on car (maybe 15hp), but it does run cooler and keep the fuel system cleaner. Where you really see the gains are on a forced induction car.
Oh about this post, You would think an 09 car from GM would be Flex fuel ready when 04 GMs are. I did read the manual and it does not make the most since because it does say to use Flex Fuel if possible, but there is a disclaimer that says to read the fuel something or another. But I did this after I put the gas in the tank. So to late anyway.
 
#24 ·
Well before I could see these recent post went this morning filled the tank up with High octane gas. So now there is a 50/50 ratio of E85 and Premium fuel in the tank and now the light went off. So I am still confused if it was not just the gas cap or what. I need to replace the cap for sure because it makes the light go off all the time and I have to keep tightening it. So fingers crossed nothing is wrong and she now feels back to normal on the power side of things, dang.
 
#29 ·
Just do yourself a favor and stay out of the throttle until that tank of fuel is gone. At part throttle the 02 sensors and fuel trims should do their job and keep it at a relatively safe air/fuel ratio, not ideal, but safe. At WOT it WILL be running lean and all bets are off. Good luck.
 
#26 ·
I have an E85 ethanol sensor if you want it. :) A couple of them actually.
 
#34 ·
wow, people have lost their mind... Why in the heck would you put that in your car if your car is not ready for it? NVM:judge:
 
#35 ·
Take it easy on him, it was an honest mistake. He was under the impression that these cars were flex-fuel capable. I was somewhat surprised to find out that they weren't when I bought mine. It is a 2009 after all. Sh!* happens!

I was actually expecting more comments like this one when I first saw this thread. Just shows what a great group of members we have here.
 
#37 ·
My apologies! :)
 
#42 ·
The E85 sensor can only be setup with Efilive for now, the PCM has to be calibrated for it, plus there is something needed to be done with the sensor as well once is plugged, we had a thread about it in the tuning section. It's not as easy as it sounds otherwise you'll have more 2 people asking for it :), Explicitsaint was one of them, in any case, tuning for E85 is fairly easy,

Change your stoich point in the calibration for E85,
change your crank fuel if you live in a region where it gets cold out
increase timing in general,
and of course, your MAF/VE calibration has to be spot on for this to work, see, a PE rape tune won't work just changing the stoich to work with E85 because the fueling would be all over the place, And yes, with your mods, you can run E85, i ran it with Kooks mids, and Scooby is testing with a CAM, (don't know if he has LT's yet), but Scooby is also at elevation so in his application, he should have injectors for it with a cam. in my application, i used to see 77-80% IDC (injector duty cycle, which is good but almost maxed, and because i like to run my crap fairly rich)

I would be trying E85 soon with my LT's, i just need to find out if our local 1/8 mile track is still open for the year :) i've been trying to get into the 7's with the ****ty 91 octane we have, so E85 should make my car .2 faster based on previous results.
 
#45 ·
I have Kooks mids now but haven't run E85 since installing them. May do so soon now that the car is running good.

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#44 ·
One shining point is that E-85 is 100+ octane!
 
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