New SGII Problems
#41
Re: New SGII Problems
Gary, what does the 2009 show for LTFT with E10?
It will move around slightly, but what's the average?
It should be positive if you have ethanol, and near zero if you have gas only.
This has been a good way for me to tell the difference if the pump is not labeled, or if I am in a state that does not require labels.
It will move around slightly, but what's the average?
It should be positive if you have ethanol, and near zero if you have gas only.
This has been a good way for me to tell the difference if the pump is not labeled, or if I am in a state that does not require labels.
GaryG
#42
Re: New SGII Problems
Gary, I'd check the compression and ignition-related items on the explorer and 05. I suspect much of your problems is age, salt or humidity-related, not ethanol. I ran E60 on my Rav4 for 6 months, (before adding a conversion) and only had a loss of 3 mpg (22 vs 25 mpg). I haven't heard Billyk complain about loss of power in his '05 with 30%.
#43
Re: New SGII Problems
Gary, I'd check the compression and ignition-related items on the explorer and 05. I suspect much of your problems is age, salt or humidity-related, not ethanol. I ran E60 on my Rav4 for 6 months, (before adding a conversion) and only had a loss of 3 mpg (22 vs 25 mpg). I haven't heard Billyk complain about loss of power in his '05 with 30%.
GaryG
#45
Re: New SGII Problems
It is interesting to know where I live in Southwestern Pa. there is no E10. It is straight 87 octane. After I run a mixture of E20-35-30---it takes less than 20 miles for my Long term fuel trims to "normalize" when I return to straight gas. On straight gas, my LFT is always under zero unless I am going up a hill and then it is no more than four point zero.
I have gotten as low as -14.9 LFT on straight gas
On straight gas going up a 9% 5/8 mile hill
On E30, I can "score"a LFT of 14.0
and drop down to zero:
update: The vehicle's LFT dropped to minus 1.6 today.
It was snowing and is in the low thirties on this drive. The vehicle's LFT value slowly but progressively drops upon deceleration/fake shifting as the vehicle utilizes this fuel. It initially has a LFT value of 2.5 to 3.0 after the initial fillup and slowly leans its self.
I'm down to 12 miles to empty on my current tank and need to fill up in the next day. Maybe I can reset my digital camera to show how rapid the LFT reset.
I have gotten as low as -14.9 LFT on straight gas
On straight gas going up a 9% 5/8 mile hill
On E30, I can "score"a LFT of 14.0
and drop down to zero:
update: The vehicle's LFT dropped to minus 1.6 today.
It was snowing and is in the low thirties on this drive. The vehicle's LFT value slowly but progressively drops upon deceleration/fake shifting as the vehicle utilizes this fuel. It initially has a LFT value of 2.5 to 3.0 after the initial fillup and slowly leans its self.
I'm down to 12 miles to empty on my current tank and need to fill up in the next day. Maybe I can reset my digital camera to show how rapid the LFT reset.
Last edited by Billyk; 11-16-2008 at 01:26 PM. Reason: more data
#47
Re: New SGII Problems
Billy, I think the SGII LFT your seeing is the current PID and not the Long Term Fuel Maps stored in KAM. The LONGFT1 PID is for diagnosing fuel trim concerns. A negative PID value indicates the fuel is being reduced to compensate for a rich A/F mixture, and a positive PID indicates the fuel is being increased to compensate for a lean condition. This is not the same as stoichiometric (14.7:1) being rich above and lean below. There is a separate LONGFT that is used for each RPM/load point of engine operation. When looking at the LONGFT1 PID, the value may change a great deal at different RPM and load points. This is because of the learned corrections stored in KAM. In other words, once the RPM/load point is learned, the A/F mixture should not need to be compensated from the learned Long Term Fuel Maps.
If your seeing a positive PID number with ethanol in general, this means more fuel is added (lower MPG) to compensate for a lean condition. On the other hand if your seeing negative PID numbers with straight gas, your reducing fuel to solve the rich conditions. Ideally, you want to use the stored Long Term Fuel Trim Maps in KAM so your not constantly adjusting the learned data. This is one purpose of KAM. If you think every RPM/load point is relearned and stored in 20 miles, I beg to differ. My mileage drops for almost three tanks even after a reset of KAM to the default setting. When you change the energy of your fuel by adding ethanol, the fuel maps all change for each and every RPM/load point.
GaryG
If your seeing a positive PID number with ethanol in general, this means more fuel is added (lower MPG) to compensate for a lean condition. On the other hand if your seeing negative PID numbers with straight gas, your reducing fuel to solve the rich conditions. Ideally, you want to use the stored Long Term Fuel Trim Maps in KAM so your not constantly adjusting the learned data. This is one purpose of KAM. If you think every RPM/load point is relearned and stored in 20 miles, I beg to differ. My mileage drops for almost three tanks even after a reset of KAM to the default setting. When you change the energy of your fuel by adding ethanol, the fuel maps all change for each and every RPM/load point.
GaryG
#48
Re: New SGII Problems
LTFT displayed on the SG is, of course, the fuel trim being applied at that moment, in real time. So yes, it will move slightly ( or occasionally, greatly ) with changing driving conditions. However, it will "hang out" at a average point.
If the "average" is positive, it is a good indication you have ethanol in the tank. If the "average" is negative, it is a good indication you are at some significant elevation above sea level.
If you switch back and forth from ethanol, especially high amounts of ethanol, back to straight gas, yes, it takes time to "re-learn".
If you switch fuel, and get right on the highway, the LTFT will adjust to highway conditions ( aka 2400 RPM and gentle load ) pretty fast ( within minutes ). However, like Gary says, until you have run the car at ALL RPM's and various load condtions, the car has not completely adjusted yet.
Gary, do you want me to give you the SG code for LTFT so you can try it in the 2009 with Florida fuel? You don't always get exactly 10% ethanol.
-John
If the "average" is positive, it is a good indication you have ethanol in the tank. If the "average" is negative, it is a good indication you are at some significant elevation above sea level.
If you switch back and forth from ethanol, especially high amounts of ethanol, back to straight gas, yes, it takes time to "re-learn".
If you switch fuel, and get right on the highway, the LTFT will adjust to highway conditions ( aka 2400 RPM and gentle load ) pretty fast ( within minutes ). However, like Gary says, until you have run the car at ALL RPM's and various load condtions, the car has not completely adjusted yet.
Gary, do you want me to give you the SG code for LTFT so you can try it in the 2009 with Florida fuel? You don't always get exactly 10% ethanol.
-John
#49
Re: New SGII Problems
GaryG
#50
Re: New SGII Problems
Just like a box of chocolates, "you never know what you're gonna get".
I just heard some insider information.
Effective Jan 1, 2009 all ethanol plants will only produce and ship E98.
What I don't know yet is, who made this decision.
If it was voluntary by the industry, or if there was some gov. mandate.
Details to follow.
-John
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