I am also wondering if E15 is out. 0 fuel trim should be E10 and that is why I am seeing negative fuel trims with premium compared to regular? They said Sept around here but it has to be marked and summer blends wont be E15 due to it wont pass summer blend requirements. That hasn't stop them before saying 1 thing and doing another.

 

According to the rule, e15 well not be mandated, just permitted. All stations that choose to selle15 must clearly mark it, and it is only permitted for 2006 and newer cars, if I understand correctly, so you won't see stations just randomly changing everything to e15 without telling you. They will actually have to spend extra money to store the e15 separately, in all likelihood.

 

sorry for the spelling errors. My phone doesn't display the comment while I'm typing it, so I have to guess.

 

I wish I could get E98 or Oxygenated E85 at gas stations.

 

Oh, by the way, I never tried to go beyond e70. The car ran great, but seemed kind of borderline at full throttle. I think I was hitting the limits of the injectors and running too lean at full throttle.

 

Ya, that would be nice. That is the best for reliable Hp but not good for mpg.

 

You are correct except they are going back to 2001. They are suppose to add a blender pump and have it marked E15 for cars 2001 and newer. The problem is 1 out of 5 cars failed that should have passed. Leaks and other problems that might of been fixed with a reset and fuel filter change. Motorcycles and small engines and boats cant use it so they want to have a waiver for premium gas to be ethanol free. Some states have approved this and there is a bill in congress but it has stalled.

Since there is E15 fuel in the hoses there will be a disclaimer to pump 4 gallons to flush the fuel out of the line for the ethanol free.

I wish I had seen the fuel trims of my old Civic when new. My fuel trims are 25 percent from when I run premium. My car is getting 43 according to both read outs. There is a lot of EGR from 40 to 65 percent. On premium EGR is 0 to 25 was normal. The ECON button lowers engine loads and makes the car feel like a truck. Pedal becomes heavier too.

I plan on returning to premium but if the 43 mpg is normal on regular I could be happy with that, but I expect it to fall quickly.

 

1st tank 42.2mpg. Filled Shell regular and the fuel trims went to 0. I am happy that the fuel trims leaned out. The EGR and timing need to change before I consider running regular. I don't like seeing 65 percent EGR and -5 timing. Timing that retarded is probably the reason for coil problems and spark plugs blowing out of the head.

What ever happen to super Ethanol? Octane was suppose to be 374 and was the answer to all the fuel octane problems. That was 10 years ago.

 

Yeah, it's that timing, man. I think the retarded timing is the reason for the low torque below 2000 RPM, and it makes the car feel slower than it should be.

Another thing: you said the Shell regular seemed to work ok, except for the timing and EGR. Fuel quality varies widely, as we've discussed here many times, so I guess you may be getting some better fuel from that Shell station.

Also, some have claimed that 93 octane fuel is more likely to contain less than 10% ethanol. I don't know how to verify that.

25% difference in fuel trims between regular and premium? How can that NOT trigger a CEL?

And the super ethanol? I don't remember much about that...it wasn't isobutanol, was it?

 

Update on the fuel trims, I ran a few errands and the fuel trims went up to what I seen on the first tank. Timing and EGR is the same but the BTUs in this tank are more. This car has a iMID which tells the range. The first tank read 456 and I got 42. It read 504 today so the range is further and it runs smoother too.


Timing at idle -5 is not normal. There is only 12 degrees to build up pressure and the heat and pressure is right when the spark plugs is firing. Honda ignition is variable which means it can hold a spark at different dwells and degrees. Having a lot of EGR means a longer spark is needed too.

The Long term fuel trims are for low to mid engine loads and Short term is mid to high loads. You have a 30 percent swing that the CEL dont come on. Having fuel trims of 10 is a cause of concern. It should be -5 to 5. It is a percent of time the injectors are open or closed from the base map. So my car running premium has fuel trims of -5 and on regular 2-5. So that is the 10 percent in mpg. My car on premium when engine loads are high the ecu usually pulls more fuel out. So if my fuel trims are -8 st and -5.5 Lt at higher loads its pulling 8 percent compared to 5.5 which means its more efficient at higher loads.

Super Ethanol was a ethanol with higher octane and required 30 percent less to meet EPA requirements.
Green Star Acquires Super Ethanol Plants- Continues Its Acquisition Program
Millennium Fuels Corp Develops a High-Octane Fuel


I believe Most premium gas is ethanol free but it still has a oxygen derived hydrocarbon.

 

You think they use esters or something in premium instead of ethanol?

That's also quite interesting about the STFT and LTFT. For fuel-saving purposes, I try to drive at fairly high load, typically 70-80, but no higher under normal circumstances. That might explain why my ECU isn't learning the LTFT. I just never give it the chance.

 

What ever it is the fuel trims shows that premium is more efficient. It might be the toluene but I think there is more in regular these days, especially around here. Esters have more BTU's and require more for the same oxygen content of ethanol. Butanol is a alcohol that BP and DuPont are working on. It is lower octane compared to ethanol but has a few less BTU's than gasoline so mpg is the similar to plain gasoline.

Maybe its the super ethanol with higher density, that would explain the 5 percent ethanol Shell had in the optimax in Europe and I heard rumors Bp bought it because Shell went with a new blend V power.

It looked like they were trying to use super ethanol to raise the octane and reduce the amount needed so food prices did not go up. What happened is they put it in the closet and raised food and gas prices.

 

couldn't of said it better myself

 

87 Octane 32.5 mpg with roof rack which will be removed soon.

 

I fill up with 91 octane because for some reason it runs better when i turn on the A/C on a hot day than when i used to put 87. It seems like it doesn't hesitate that much from take off...... oh and cause it still fills up with under $40 bucks =)

 

I filled up with 91 octane once, noticed zero difference and switched back to reg.

 

I have a new car and it does take a little while for the ecu to adjust so saying nothing happens on the first tank your probably right but that does not mean next tank wont give better mpg. I got 42.2 on what ever the dealer put in and I filled with Shell regular and got 43.3 but the fuel trims are very high and timing is -5 degrees which means 8 percent fuel is added and the spark plug is firing after top dead center.

My old car had -5/-10 fuel trims all summer which means 5 to 10 percent less fuel is needed. That is a 12 to 18 improvement in fuel consumption. Timing too was 8/9 with premium compared to -5. Honda says 8 degree timing at idle.

You know when a car is running regular when at 60 mph they pull out when you are doing 70 forcing you to brake and they take a mile to get up to 70. They think their car is fast because the engine is at red line but not accelerating. I use to think they just pulled out to slow traffic until I passed and heard the motor.

150 miles with mid grade and fuel trims and timing finally looking better. Fuel trims 4 compared to 8 and timing now 2/3 degrees. Honda's are just slow to adjust.

 

mid 20's city low to high 30's (mpg) hwy depending on where i'm driving on 87

 

Still using 87 Octane hit 9k on car gas mileage now at 32.9 mpg still have roof rack on.

 

Fuel trims are finally leaning out and my mpg is up too. Last tank 43.6 and this tank I am close to 45 mpg. It took 7 fill ups before the fuel trims started to move which would be about 5 full tanks of gas. It still has a way to go before they are the same as my other car.

Using Shell V power. Mpg dropped with Bp ultimate so going to hold off on using it for a while.