This is one I really have a very hard time buying. I can't imagine there's enough resistance provided by a slightly overfilled crankcase to make a measurable difference in the real world. Possibly an incredibly minor one under controlled laboratory conditions...but there are just too many variables in real-world driving to accurately measure the effect.

 

I don't think the presence of ethanol is nearly as big a deal as we once thought it would be. Granted there are other factors involved but my best tanks have been since the introduction of 10% ethanol in the gas. I went from 34 or so mpg last summer to 39 or so this summer. I would have been happy to stay the same but I went up so any hit I took from ethanol was more than made up for. I use Hess gas almost exclusively mainly because it is common around here and is about the cheapest. Never any issues with it.

I have also found that city driving (in heavy traffic) in cooler weather kills the mileage. Too many restarts to keep the cat warm. That shouldn't be a big problem this time of year in Texas.

I'm with Tim - find a route that allows forward progress so that even if you are forced to run the ICE you are getting miles for that gas use.

Fill your crankcase with what the manufacturer recommends. 4.5 quarts at an oil/filter change.

If you are going into EV mode then you aren't in one of the red environmental control settings so that isn't your problem. But, since you said that you are still in the 90's then you are probably seeing some a/c use to keep the battery cool. Send some of that warm weather up here - I'm taking a hit this week in the cool weather....
Good luck.

Ray

 

Hi Houston

This has happen to me 3 times with 30,000 miles so far, it's ethanol in my case. There is little need for winter gas here in South Florida, but when I travel to Orlando during the winter, I stay away from their pumps.

In the '05 Workshop PCM/Emissions Diagnosis manual on page 1-39 it states:

"Long term fuel trim is represented as a percentage, just like short term fuel trim, however it is not a single parameter. There is a separate long term fuel trim value that is used for each RPM/load point of engine operation. Long term fuel trim corrections may change depending on the operating conditions of the engine (RPM and load), ambient air temperature, and fuel quality (% alcohol or oxygenates)."

What this is about is ethanol is alcohol and an oxygenate. There are a number of problems that occur when this crap is added to gasoline in the FEH. First, it is not as combustible as gas, and does'nt produce as much energy. Second, the oxygen sensors pick up on the "oxygenates" and this send a message to the PCM that the engine is running lean (stoichiometic air/fuel ratio higher than 14.7:1). The PCM adjust the fuel mixture to run much richer and you burn more quanity of fuel (gas/ethanol mix). Third, the long term fuel trim value that is used for each RPM/load point is changed and stored in the Keep Alive Memory (KAM) located in the powertrain control module (PCM). This causes your engine to continue to run rich and burn more fuel even after you refill with straight gasoline untill all RPM/load points have been relearned and stored back in KAM. It has taken up to 3 tanks of gas for me in the past to reset KAM and get my normal MPG.

In the future when this happens to me, I'm simply going to reset the KAM to the default mode after I burn that tank off. To reset KAM, disconnect the 12 volt battery ground for at least 5 minutes. Anytime you have problems with the fuel system that causes a rich mixture, the service techs are required to reset the KAM. An example would be a bad fuel injector that was causing the PCM to run the air/fuel mixture rich. After replacing the fuel injector, the KAM must be reset according to the workshop manual.

GaryG

 

Ahhhh. That ethanol. My mileage went down .4 when I first started using it and another .4 when I have started going to Costco for gas. I doubt that Costco has a higher percentage of ethanol. I have a beef with ethanol as we are going to manufacture it here on Kauai using COAL as part of the process. Not only do we use land that could be used for other vegetation, like organic vegies, we are going to pollute our space with COAL??? Nothing makes sense to me any more.

Thanks for all the tips. I studiously followed them for a while and did not get results. Probably not patient enough. I like to be able to just drive and not have to deal with it, especially with no results.

aloha,

 

But also, in all fairness, GaryG did not use ethanol for more than 1 tank, and therefore, his car's long-term settings probably did NOT have enough time to properly adjust to the ethanol mix.
46% of the USA uses ethanol for some or all of the year, and while ethanol FOR SURE reduces MPG, it is not quite so bad after say, 3 tanks.
I use 10% for 6 months a year, and see my results below....

Making ethanol from coal ( well, probably cane sugar, but the heat for distillation comes from the coal... ) is not my first choice. HOWEVER....
20,000 btu of heat from coal will make 80,000 btu of ethanol... so there is a 3x advantage to the process....(60,000 btu net) but that discussion should be in a new thread.

-John