Finally dynoing the Focus 5/2/12

[JSR84]

Good info ChrisRo!

[Kabigon]

Originally Posted by ChrisRo

The stoich itself is a set value in the PCM at 14.079, but the car itself won't actually know what fuel it has in the tank. Since ethanol is a regulated deal, it just makes sense to include that in at least US calibrations.

The only thing it knows is the quality of the fuel in terms of adaptive spark and knock sensors. If it's 87 octane, it's not going to be aggressive as if you fill with 93 octane. The knock sensor strategy is intelligent enough to add/subtract based on audible feedback.

It also will know the commanded and actual lambdas. So, the car just needs a proper lambda, and needs knock sensors that can add/remove timing based on fuel quality. In those terms, yes - it will know the fuel quality.

The proper lambda for E85 and the proper lambda for 100% gasoline, for a given car/mods, will be the same. If that lambda too lean or too rich for gasoline, it's going to be too lean or too rich for E85. The only difference is when you speak about it in terms of air/fuel ratio. So really, the car doesn't need to know what fuel is in it. Make sense?

Hope this helps!

Here is some interesting reading on this subject:

In order to maintain proper fuel control, the PCM strategy needs to know the stoichiometric Air/Fuel Ratio for use in the fuel pulse width equation. On pre-2000 MY flex fuel vehicles, the percent alcohol in the fuel was determined by reading the output of the Flex fuel Sensor. The percent alcohol was stored in a register called Percent Methanol (PM). Although current alcohol-blended fuels only include ethanol, the percent methanol nomenclature has persisted. On 2000 MY and later vehicles, the Flex Fuel Sensor has been deleted and PM is inferred. The strategy to infer the correct A/F Ratio (AFR) relies on the oxygen sensor input to maintain stoichiometry after vehicle refueling occurs.

http://www.motorcraftservice.com/vdi.../OBDSM1202.pdf
(see pages 62-63)

[ChrisRo]

Originally Posted by Kabigon

Here is some interesting reading on this subject:

In order to maintain proper fuel control, the PCM strategy needs to know the stoichiometric Air/Fuel Ratio for use in the fuel pulse width equation. On pre-2000 MY flex fuel vehicles, the percent alcohol in the fuel was determined by reading the output of the Flex fuel Sensor. The percent alcohol was stored in a register called Percent Methanol (PM). Although current alcohol-blended fuels only include ethanol, the percent methanol nomenclature has persisted. On 2000 MY and later vehicles, the Flex Fuel Sensor has been deleted and PM is inferred. The strategy to infer the correct A/F Ratio (AFR) relies on the oxygen sensor input to maintain stoichiometry after vehicle refueling occurs.

http://www.motorcraftservice.com/vdi.../OBDSM1202.pdf
(see pages 62-63)

Good read. So what I'm saying sounds like it really applies to 2000 MY and up. However, wideband data only became available in most Ford models over the last 3 MY's, and as little as 1 MY in this case. So, lambda wasn't available.

That's interesting. The tough thing is that I've never actually seen the logic they're claiming in any PCM codes. This is probably because I never tune flex vehicles and always tune gasoline, E10 or E85.

I need to dive into a flex fuel PCM code.

[cessna1]

On 2000 MY and later vehicles, the Flex Fuel Sensor has been deleted and PM is inferred.

Actually my 2001 Taurus still had a sensor made by Siemens that measured the ethanol blend in the tank. Pretty much figured changes out immediately.

[TORQUERULES]

Originally Posted by ChrisRo

I can guaruntee that they wouldn't put a wideband sensor in the car and not use it. Coyote Mustangs still need tuning, even though the wideband may be adjusting for additional mods. That explanation is my post before this. However, you're absolutely right - there is correction going on with the widebands (or wideband in this case) and it does allow the car to have a little bit of "wiggle room" to mod without NEEDING a tune to hit targeted air/fuel ratio (which comes from the Desired Lambda at WOT table within the tune). Need a tune and should have a tune, is where it gets tricky.

The factory wideband sensors on these are extremely accurate, and we actually believe them as much as some of our lab equiptment. We've tested it back-to-back with Dynojet Wideband Commander, AFM1000, and UEGO's (junk). They're very accurate.

Your last paragraph is exactly right.

I agree... Good tuning is necessary, but at least Ford has given us some wiggle room again. Almost like a higher tech revival of the old A9L EEC IV 5.0 HO processor days. :-)

[Ulf Wafflestein]

Originally Posted by 1turbofocus

Only CL = Closed Loop fuel uses the front o2 for fueling , OL = Open Loop uses the base fuel tables and no o2 for WOT fueling , If you go WOT then you are using your OL fueling , its more what your trying to log with then your not going OL

Then your to rich and loosing some power/torque


Who did your tuning

Tom

You aren't local so I don't feel bad for calling you an idiot for not knowing grammar. Come on man, don't make yourself look like such a dullard.

[Sonic_HedgeHog]

Originally Posted by Ulf Wafflestein

You aren't local so I don't feel bad for calling you an idiot for not knowing grammar. Come on man, don't make yourself look like such a dullard.

Yo Noob...

Learn your place and follow forum rules before throwing daggers.

[twoblue]

Originally Posted by Kabigon

Here is some interesting reading on this subject:

In order to maintain proper fuel control, the PCM strategy needs to know the stoichiometric Air/Fuel Ratio for use in the fuel pulse width equation. On pre-2000 MY flex fuel vehicles, the percent alcohol in the fuel was determined by reading the output of the Flex fuel Sensor. The percent alcohol was stored in a register called Percent Methanol (PM). Although current alcohol-blended fuels only include ethanol, the percent methanol nomenclature has persisted. On 2000 MY and later vehicles, the Flex Fuel Sensor has been deleted and PM is inferred. The strategy to infer the correct A/F Ratio (AFR) relies on the oxygen sensor input to maintain stoichiometry after vehicle refueling occurs.

http://www.motorcraftservice.com/vdi.../OBDSM1202.pdf
(see pages 62-63)

Anyone remember the Super Stallion concept/show car it was flex fuel and I believe had the system described above.

[FocusBoy58]

Originally Posted by Ulf Wafflestein

You aren't local so I don't feel bad for calling you an idiot for not knowing grammar. Come on man, don't make yourself look like such a dullard.

Learn your place boy. Now go sit in the corner and think of what you did.