Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - I want to get to the bottom of this ethanol killing my mpg

shovel · 10-05-2009, 03:52 PM

My cars are a 2001 S10 4.3L with a custom PCM tune (increase polling rate of emissions/closed loop sensors, adjusted fuel map to compensate for air intake & exhaust changes, eliminate EGR, disengage a/c on heavy throttle, increase trans line pressure, reduce torque management % by half) and a 1992 Tempo refitted in 1993 for CNG/gasoline dual fuel by Metropane, Inc, whose engine management devices circumvent the Ford ECU in both fuel modes. I am not closely familiar with the capabilities of this system yet, but I have observed through experimenting that the standard Ford DTC's can still be instigated (as an example, bypassing MAF produces the appropriate mav volts low DTC - no air rushing past wire = wire gets hot = increased impedance = reduced voltage), and I can observe literally no difference in engine behavior or per-tank fuel mileage on "oxygenated fuel" vs. the "100% gasoline" sold at a nearby Love's station.

I really don't know, nor am I in any way equipped to determine what difference there is between your observations and mine, other than the observer of course. I am saying that I have two cars which are utterly indifferent about oxygenated vs. "100%" gasoline.

So what we have is, either there is a mechanical difficulty on all of the vehicles you have observed, or one of us is ignorant/delusional/absent-minded/lying/etc, or there is a drastic difference among the fuels we have available to us. Obviously nothing productive can come from speculating about each other's sanity or intellect so we're left with the mechanical differences among our observed vehicles, and the regional differences which may affect the actual composition of the fuel and weather conditions in which it is stored and burned.

In any case, for your sake I hope you are able to find a workable solution so you can save that money. Maybe a mild forced induction such as those high power electric "superchargers" - not the boat cabin fans, but the 25k rpm ones that stand a chance of giving you half a PSI or more - to increase your effective compression ratio?

10-05-2009, 03:52 PM	#95 (permalink)
shovel Master EcoModder Join Date: Feb 2009 Location: Phoenix Posts: 593 Thanks: 106 Thanked 114 Times in 72 Posts	My cars are a 2001 S10 4.3L with a custom PCM tune (increase polling rate of emissions/closed loop sensors, adjusted fuel map to compensate for air intake & exhaust changes, eliminate EGR, disengage a/c on heavy throttle, increase trans line pressure, reduce torque management % by half) and a 1992 Tempo refitted in 1993 for CNG/gasoline dual fuel by Metropane, Inc, whose engine management devices circumvent the Ford ECU in both fuel modes. I am not closely familiar with the capabilities of this system yet, but I have observed through experimenting that the standard Ford DTC's can still be instigated (as an example, bypassing MAF produces the appropriate mav volts low DTC - no air rushing past wire = wire gets hot = increased impedance = reduced voltage), and I can observe literally no difference in engine behavior or per-tank fuel mileage on "oxygenated fuel" vs. the "100% gasoline" sold at a nearby Love's station. I really don't know, nor am I in any way equipped to determine what difference there is between your observations and mine, other than the observer of course. I am saying that I have two cars which are utterly indifferent about oxygenated vs. "100%" gasoline. So what we have is, either there is a mechanical difficulty on all of the vehicles you have observed, or one of us is ignorant/delusional/absent-minded/lying/etc, or there is a drastic difference among the fuels we have available to us. Obviously nothing productive can come from speculating about each other's sanity or intellect so we're left with the mechanical differences among our observed vehicles, and the regional differences which may affect the actual composition of the fuel and weather conditions in which it is stored and burned. In any case, for your sake I hope you are able to find a workable solution so you can save that money. Maybe a mild forced induction such as those high power electric "superchargers" - not the boat cabin fans, but the 25k rpm ones that stand a chance of giving you half a PSI or more - to increase your effective compression ratio? __________________ Work From Home mod has saved more fuel than everything else put together.