TurboEF9

Tries to correct A/F based on readings from the O2 sensor alone.

spike

so really you can't tune any part throttle at all.. it will adjust it automatically.. excellent.. so just worry about full throttle then.. thanks man!

88crxSi

WOT (80% and more, OPEN LOOP) uses the stored data in the ecu (stuff u change w/ ghetto dyne).

less the 80% its in closed loop mode and constantly adjusting A/F based on O2 readings. It gets the BASE readings from the open loop table.

zac

Can always unplug the stock O2 sensor...force the ECU into open loop. While in closed loop, the ECU uses the fuel maps as a base, and then trims/enrichens based on the O2 sensor...so there is some value in part throttle tuning. -Z

purpleworm

In the stock computer there is a limp home map isn't there? When an O2 sensor dies in your car you notice the gas mileage start to suck normally. Anywhere past 80% throttle it uses the base fuel settings in the computer does it? It supplies fuel by percentage of the base value (IE. supply say 30% more fule at this RPM and MAP reading).

My brain hurts!

zac

Kinda sorta...there is a limp mode, which isn't really understood all that well yet. Basically, when the ECU determines it's program is corrupt (via it's internal checksum routine) it'll enter limp mode. If you ever run into this, you'll get a CEL and the LED on the ECU will stay lit. The car will run horribly, it's almost impossible to drive.

You've got the right idea. The ECU uses two different inputs (RPM and Map signal) to control fuel and timing. The combination of these two inputs make X and Y on a chart, so at X RPM and Y vaccum, hold the injector pintle open for Z milliseconds, or advance or retard ignition timing Z amount. Download a copy of Ghettodyne and you'll see what I mean. -Z