E85 In A 2001 Denali Xl

dthakoor · July 22, 2010

I have a 2001 Denali XL with a 120K miles on it. I have been using E85 in the truck for a couple months now with no serious issues. My mileage did slightly drop and the check engine light did come on. I can't remember the exact code (possibly p0171 or p0174), but I believe the E85 was causing cylinder 1 and 2 to run rich. When I use regular E10, the code clears itself. Basically I was wondering if there is anything I can do to continue using E85 and not trip the engine light. Possibly some kind of O2 sensor mod or PCM tune. Thanks for any advice in advance. -D-

[email protected] · July 22, 2010

I have a 2001 Denali XL with a 120K miles on it. I have been using E85 in the truck for a couple months now with no serious issues. My mileage did slightly drop and the check engine light did come on. I can't remember the exact code (possibly p0171 or p0174), but I believe the E85 was causing cylinder 1 and 2 to run rich. When I use regular E10, the code clears itself. Basically I was wondering if there is anything I can do to continue using E85 and not trip the engine light. Possibly some kind of O2 sensor mod or PCM tune. Thanks for any advice in advance. -D-

From those codes, looks like you need to richen up your fuel trims. I don't think that's a "flex fuel" vehicle so the computer won't automatically adjust within the preset parameters and has to go a little out the parameters to make it ideal. It SHOULDN'T be a problem running the engine on e85 with the light on, it's just telling you that it had to richen to protect itself from running lean. I don't know how the injectors and whatnot will hold up to e85, but it's your truck and you can do what you want with it.

desrtrat · July 22, 2010

I have a 2001 Denali XL with a 120K miles on it. I have been using E85 in the truck for a couple months now with no serious issues. My mileage did slightly drop and the check engine light did come on. I can't remember the exact code (possibly p0171 or p0174), but I believe the E85 was causing cylinder 1 and 2 to run rich. When I use regular E10, the code clears itself. Basically I was wondering if there is anything I can do to continue using E85 and not trip the engine light. Possibly some kind of O2 sensor mod or PCM tune. Thanks for any advice in advance. -D-

if the motor was not engineered to run E85 DON'T..E85 is about 60% VE of gas. which means you need about 40%+ more fuel to run properly. your running VERY lean. there are retro fits to convert over to E85. biggest is larger injectors and a tune. not sure if your fuel pump and regulator need changing also. i would look into the change over after you look at what it is going to cost to retro fit everything, millage decrease with E85 over gas, even if the E85 is cheaper per gal. i myself would not spend the money on decreasing my mpg.

good luck

dlstewart01 · July 22, 2010

Not only were the injectors bigger, the fuel rails are stainless steel, E85 is more corrosive, There is a larger fuel pump, the early engines had a sensor to detect the presence of E85 and of course a tune. There is a TSB on the problems of using E85 in a vehicle not designed for it, I don't recall what it is.

96chevy7.4L · July 22, 2010

Oh if it runs to lean it could burn a piston and that means you'll be buying another motor. Just my opinion.

r1byker · July 23, 2010

Just curious what the attraction of E85 is to you; you're not experiencing no big problems now, but eventually you'll damage your motor. Certainly not worth it for any cost savings in fuel.

Zembonez · July 23, 2010

I don't believe there were any E85 compatible GM engines in trucks prior to 2005. You could really be screwing up some equipment here that wasn;t designed for use with alcohol.

ColoradoSkiCountry · July 23, 2010

NEVER EVER EVER Run E-85 in an engine that was not designed for it!

Stevens03 · July 23, 2010

With all the above stated as true, Diablo makes a tuner that has an E85 tune that will be safer to run E85 in your truck. It still could hurt the truck in the long/short run, but it's better than running E85 without it.