So i decided to fill up with a few gallons of 91 octane just to clean out my fuel system. (i only have a single E85 map) and the car runs normal except it idles rich (12.5-13.0 on the wideband) Im just trying to do this just to clean out my fuel system since i haven't touched pump gas ever since i switched to E85 over a year ago. Idling a little rich wont hurt anything will it?

 

This is all sorts of backwards.

 

It's good to run a full tank of pump gas, most E85 users don't understand this and just neglect it and end up with issues.(Waiting for everyone to post "I have xxxx miles on E85 with no issues whatsoever"), not yet they don't. Best to not boost at all and get a 2nd map for 91 started soon.

 

Well you wouldn't want to boost with that in the tank given that the timing would be far to aggressive (I'm assuming). Its idling richer because E85 has about 30% less energy content then regular 92, so your injectors are injecting a lot more fuel then needed since your ECU thinks its E85.

You won't do any damage idling that rich for a short period of time. But if you were running you car with that fuel more often, you could do damage via bore wash. You wouldn't want to be idling the car any richer then 12.5 A/R (not that your car should be tuned to idle that rich anyway).

I also don't see the point of running a tank of 92 (or whatever octane) to clean out the system....

 

Just take it easy because your map will be way off, especially under boost, and you'd get pretty bad pre-detonation because of the timing if I'm not mistaken (which I could be lol)

 

lolwat? E85 is way cleaner than gasoline ever dreamed of being. If it gives you problems its because you had a dirty, gunky, fuel system that got cleaned out by the ethanol, and all that gunk ended up clogging something..

 

So a 12.5 AFR at idle is rich enough to do bore wash? I figured it would have to be way richer

 

Idling at 12.5 is pretty rich for an idle. Its not going to do anything in the short period that you're running gas. I would only worry about it becoming an issue if you were running that tune for an extended period if time.

 

Yeah I only put a half tank in and I'm going right back to e85. I just wanted to try cleaning out the fuel system.

 

LOLNewb, Waiting for someone to question it. E85 clogs up the fuel injectors, pump gas once or twice a year cleans them out. Sure your pistons look shiny but do a little research on what E85 does to your fuel system compared to the much less problematic unleaded fuel hence the reason the OP did this to begin with.

 

Very True lol

 

I just run a can of sea foam through it with a full tank of E85. I also have a dual map setup so I could switch over to run 93 thru it. Highly recommend a dual map tune if possible.

 

A little off Topic. I have e85 in my car right now. I want to switch back of to pump 93. I have a map switch for the other map. I want to know if i can run the car really low on E85 and just fill it back up with Pump and change the maps, or if i need to empty the tank via the drain plugs then put pump in?

 

You can run the tank low on E85 and the fill up with pump. I would personally fill up again after 50-100 miles to knock down the percentage of E85 even more. Draining it would be best but not needed as long as there's not several gallons of E in the tank.

 

Should be fine just drive it easy. And stay off the boost