how would you adjust closed loop afr
#5
Evolved Member
Thread Starter
Some wide band controllers like the Zeitronics ZT-3 can simulate a narrow band output. If you wire the NB output from the controller into the front O2 input to the ECU, you can adjust the stoich (14.7 AFR) voltage set point in closed loop to move it either lean or rich.
#6
EvoM Guru
iTrader: (7)
A narrow band normally outputs 0.1 - 0.9V. It generates 0.5V at 14.7 AFR or "stoich". If the ECU sees 0.5V coming in on the front O2 NB input, it thinks everything is in balance and so doesn't start adjusting your trims.
The ZT-3 set point can be configured to output 0.5V for an AFR anywhere between 9.6 and 19.6. This "fools" the ECU into thinking that a lean AFR like 16.0 (for high mpg), or a rich AFR like 13.5 (so you can idle with big cams), is actually OK. There is no need to reprogram your ECU. In fact you can run it in closed loop and take advantage of the dynamic fuel trims like Mitsubishi intended.
Maybe you could tell us what you are trying to do so we can advise on the best approach?
#7
Evolved Member
Thread Starter
I know how simulated works and all that you posted but I didn't know the zt3 had adjustable set point.
So that's not adjusting anything in the ecu as I asked.
Exactly I have lumpy cams amongst other mods and wanted to play with afr at idle and stay closed
So that's not adjusting anything in the ecu as I asked.
Exactly I have lumpy cams amongst other mods and wanted to play with afr at idle and stay closed
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#8
Evolved Member
iTrader: (6)
I don't see the problem with getting only the idle open loop.
It made the low trim drift a little bit, so I turned it off like you see in the HZ crossover table. From my testing it has the effect of LTFT staying at zero. I don't need it anyway.
Last edited by domyz; Nov 2, 2013 at 12:49 PM.