hi,
just wondering if the engine ecu in tw/kw's will actually take time to adjust AFR ect to recent modifications eg HF cat/Headers ect ect....

cheers in advance

hi,
just wondering if the engine ecu in tw/kw's will actually take time to adjust AFR ect to recent modifications eg HF cat/Headers ect ect....

The only adjustment it makes is to the fuel trims, which it does when operating in closed loop mode from feedback by the oxygen sensor.

Exhaust and camshaft changes can change the measurement of AFR for various reasons related to gas flow through the engine, so the fuel trims can be expected to change a bit after these changes.

The info I've read suggests that most Mitsubishi ECUs at least since 2000 have a five or 6 minute "cycle" for the long term fuel trims to settle - this time reflects the actual cumulative time operating in the respective rev ranges for the low (or idle), medium and high speed fuel trims. I have no idea of the behaviour of the Bosch ECU in the 380, but expect it would not be drastically different.

The recommendations I've read suggest idling the engine for at least 10-15 minutes after a change (including disconnecting the ECU from the battery), and taking the car for a 20 minute cruise (trying to maintain a relatively constant engine speed in the 2000-3000 rpm range) to fully establish the fuel trims. These periods also allow the engine to get fully up to operating temperature and ensure the ECU is in closed loop mode to do the AFR evaluation.

I understand that the stock ECUs can cope with fuel trims up to +/- 25% of nominal fueling, and with a stock engine/exhaust configuration would normally be within +/- 10%.

3rd gens lack a knock sensor, so the ECU can't adjust ignition timing based on the RON of the fuel, or to combustion changes arising from changed gas flow; 2nd gens and 380s do have a knock sensor, and are more adaptive in this regard.

yeah cool i thought it was a reallyyyyy long time to adjust but obviously not , trying to get haltech interceptor at the mo anyway:hmm:

thanks heaps