blstoff

this is not true . the only time the ecm will command anything leaner than 14.64:1 is when it enters coasting fuel shut-off mode , orif stoich was changed in thetune. I see quite a few people w/ lean tip-in problems(not tuned properly)buta/fwill always toggle around stoich when in closed loop .

cliffyk

[/align][/align]I, and my wideband sensor, and a lot of SAE literature (yes, I am a member of this geek squad too) disagree. [/align][/align]Many cars run as lean as 16:1 and more cruising on level ground at 55-65 mph. There is nothing magic about the stoichimetric mix, it is optimal only under normal engine load conditions.[/align][/align]

blstoff

you can think what you want. I've been tuning fords/mustangs for over 10 yrs& have taken several advanced training courses through SCT ,I think I know by now how ford strategies work . I too have a w/b & have datalogged 100+ ford vehicles , a/f will never toggle around 16:1 in closed loop w/ a stoich of 14.64:1 . if your seeing 16:1 a/f in closed loop than your maf is more than 25% off or you have a bad 02 sensor . it will run stoich at any load in closed loop . throttle position decides open/closed loop after cold start-up ends & TP for open loop is just over half throttle .

closed loop- when the engine is using input from the 02 sensors to control the engine to 14.64:1 a/f ratio .

I would like to see this literature you are speaking of .

cliffyk

I have not been deep enough into Ford/Mustangs to know how they do it, however most Jap econoboxes will go as high as 16.5:1 at level ground cruising.[/align][/align]If Ford isn't doing this they are missing the boat fuel economy wise. [/align][/align]As for distributing SAE papers, they have people come to your house and shootyou and your familyfor less than that. Go to their website and you'll see how tight-lipped they are...[/align]

blstoff

yes , I agree . ford could lean it out under certain conditions . thisphoto is the base fuel table for 99-04 gt . ford uses TP vs. RPM so the ecm will command this no matter what load is . 1=14.64 .

Nitti00GT

The guy that tuned my car used a chart like that to set the a/f ratios in open loop. He set it so that my car stayed in open loop longer because my O2s would not read properly dude to the fact they weren't heating up fast enough. He also swapped out the generic Bosches I put in for Ford factory O2s.

Eagle2000GT

Most tuners will do that when installing Long-tube headers. Mine did. You just don't want to run the car hard until it switches over.

cliffyk

The OEM sensors have 3.3 Ohm heaters, Bosch's universal replacements have 6 Ohm heaters and should not be used on our cars, they will not heat quickly enough (or enough at all) as you have discovered.[/align][/align]Bosch does have a series of exact fit OEM replacements that will work properly, they are p/n 15716, 15717, and 15718; depending on upstream/downstream left/right...[/align]

JEG447

I have a headache!