Thread: Petrol Fuel maps,

From what I can find/read,
a normal modern car fuel map starts in the OPEN fuel loop,
This runs the tune and is a manufacturer spreadsheet of throttle position/speed/temp/revs. regardless of O2 sensor. The ECM does not LEARN.


it then, after reaching several parameters, temp, time, speed, more?
switches to CLOSED. the ECM learns, the ECM uses the O2 sensor to keep the cats happy.

but,

under load ( and the amount of load varies, from manufacturer to manufacturer, ) the ECM switches back to OPEN,,
back to the manufacturers spreadsheet.

So, the exhaust is clean when the car is slow, but dirty after that?

The pic below is from a bike,, but gives a good example of when your O2 sensors are actually being used,,



all these are just my thoughts,, but
would be REALLY happy to hear ANY opinions on this
PM me, write me a letter, send a pigeon

Fuel map.jpg

it goes closed loop when it reaches a certain temp.
ina d2 v8 its 65 degree (from memory)
an ls1 is 75 degrees

also ecu will ignore o2 sensor at wide open throttle (wot) as you dont want the engine leaning out at wot.