Well I pulled up to the pump today to fuel the wifes civic and damned if there was'nt stickers on the pumps "may contain 10% enthanol". This is new to our town. We've always had 93 octane down here so is this something I need to address for the Buick? Car was tuned by the previous owner but will it need any tuning for this? Thank you.
You say it was "tuned" - with what and for what?
What year Civic is this?
A normal ECU tune of OB2 vintage will not only compensate for the small AFR changes in closed loop but also will often have a "learn" function for all open loop function.
I have the following vehicles (not counting FFV's) in my stable--all run perfectly on E20 (20%) or higher ethanol;
2004 Saab Aero 2T (turbo)-- I run E20 in it instead of the 90 octane spec'ed. E20 is 92 octane. I have run E28 in it on long cruises to check mpg and long term fuel trims. It now has approx 70,000 miles on it. Safe limit for E% in this car is likely 37% without an ECU tune upgrade.
2000 GMC Yukon 5.3L -- it normally only drinks E20 though I have had it up to E60 for brief (1 tank) escapades. No codes- trims acceptable. 157,000 miles.
1996 5.7L Silverado 230,000 miles-- also normally runs E20 though I did something I should not have- I had E60 in the tank when I found out I was headed to your state on hurricane relief and had to pull a very heavy trailer to Galveston. It survived that tank just fine even though I was headed into a a stong headwind and hill climbs. LTFT's never got over +10.
All of the above were switched from E0 to ethanol (Silverado at 100,000 miles) and all have factory original fuel injectors and pumps. No fuel parts have failed. All have the factory tune.
The only issue (other than something caused by an unknown in your aftermarket tune) would be to watch for fuel filter plugging if your car has a lot of miles on it (gasoline can leave deposition on tank walls that ethanol will clean). The other source of filter plugging can come if the station owner was too "cheap" to clean his tanks of water and deposits before his conversion to E10. Pity the guy who pulls up first to fill.
Again- find out what this "tune" was all about- if it blocks the open loop learn function then IF you also have power adders or modified compression you could be a tad lean at WOT if the tune's open loop map is not rich right now.
Ok- just noticed- you were asking about the Buick. It is pretty much the same deal.
