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evo IX idle issues

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hi all

looking for some input.

trying to get an evo IX have a steady idle.

here is some background on car.

fully forge engine with 272 cams and FIC 1800 injector (low impedance) ecu AEMv2

cant get car to idle with a 14s AFR. its smooth and constant at 12.5 which i think is too rich as this is still a road car.any ides are am trying to to mircles based on cams and injector size?

thanks for any input

What fuel are you using? i have no personal experience with those injectors but I expect that is where your issue lies. The larger low impedance injectors tend to be tricky at low pulsewidths due to non linear behaviour and it may be impossible to get it to idle ok at 14:1 AFR. I assume you have tried the other tricks, advancing timing, reducing overlap and increasing idle rpm.

Thanks for the input

I tried advancing timing and increasing idle both help but not that much.

\ didn't think about reducing overlap will try that and see.

Agreed my experience with larger injectors esp on the 4g63 your probably at the point below dead time and that's why your getting the surge as the pintle is probably bouncing erratically. I had this issue on a supra with FIC 1450s and a link ecu, i had the set the minimum pulse width .1 MS above dead time to keep the car stable at idle. I ended up with a 12.6 - 13.3 idle on it on pump gas where as on e85 it would idle perfectly fine at 13.8 - 14.2. I would find the lowest AFR you can get a smooth and consistent idle and set your minimum pulse widths at that point.

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