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The E85 Thread... Questions and Answers





why is it possible to essenitally just run e85 on a basically stock engine on this car?
Almost any vehicle can run on E85 with just a few changes, key word being almost. The big oil companies make it seem like you need an entirely new car or you need to spend thousands of dollars to run E85. Even old carburated vehicles can be easily converted to E85, by just buying larger jets for the carb.
 
I m not aware of any 3800 PCM that has flex fuel capibilty. The LS4's grand prixs can use a flex fuel sensor though.
 


what if i wanted to run a flex fuel setup though

Newer cars do this much easier, since they actually have a way to measure the ethanol content and adjust the ECU accordingly. We have to do this manually to the w-body platforms, as they were not equipped with the software or sensors at that time. Hence why one would have to manually check the ethanol content in a given tank of fuel, and then adjust the stoichiometric targets in the tune to really dial it in.

Note that E85 is pretty forgiving though. As in even this coming winter, when it is more like E70, than E85, I will not change my tune. I will just let it run on the rich side for several months (unless I have some issues, which I would report to this thread if so!)
 
In theory i could build a flex fuel tune for 42# injectors. The stock 3800 ecu will fully support it without the need of a flex fuel sensor but i would need to do some testing and i would expect it to be limited to a specific OS for awhile.
 
And btw flex fuel sensors are old news. They are to expensive and offer little to no value in a modern car. Gm discontinued use of them years ago.
 
Some gm cars came with virtual flex fuel algorithims . in theory when the fuel trims go out of normal tolerance it references a sloped Afr target and adjust itself till it gets to a acceptable range. Which eliminates the need for any physical sensor however it never ended up working out for gm so they went back to the physical sensor
 
And btw flex fuel sensors are old news. They are to expensive and offer little to no value in a modern car. Gm discontinued use of them years ago.

Interesting.. Any idea when they came out? I wonder why they didn't put them in the 97-03 GTPs! Wish we had them built in...
 


Gm has been doing flex fuel since at least 01... it is usually only offered as an option on their common fleet vehicles.
 
What cars went back to using sensors?

Either way if they managed to make it work good enough before it would be good enough for the average gtp owner with a 15 year old car.
 
The later impalas, almost all their SUV's and other regular vehicles sold to the public not just fleet. They stopped for about 2 years iirc making flex fuel sensors and then staryed again. Also a a lot of the holden vehicles got them as well.
 
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