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'''Idle Air Control''' The idle stepped does something, but I'm not confinced it's right. I connected the 4 wires from the stepper to the A,B,C & D channels (on the EC18 connector) going clockwise round the motor looking at it from the connector end. My stepper is an "anti-stepper" like Marcell's... It was operating the wrong way round at first. '''Idle controls''' Idle afterstart RPM (added value?) - Value to add to base idle speed when the car is first started. Idle afterstart duration (s) - the duration to do the above for. IAC afterstart (steps per 160 rpm) 0 is OK (this was a hint to the ECM, dropped from firmware recently) Max steps to extend - total number of steps the motor can do. I managed to shoot the pin out of the end of mine. Don't do this as they get stuck in awkward places... IAC step sequence - Lots of things, depending on how you wire up your motor. Mine was 201. ie drive C, then B, then D, then A. stepper speed (ms) - Speed motor moves at. ie time between steps. 0 ms is fast and can shoot the pin a long way (see earlier). 3..7 msec is common. Surprising that your stepper works so fast. iac_conf RAW - bitflags, see global.h . The values you copied from Marcell should be fine (precise idle=on; stepper=on; asymetric PID=whatever you like) See the IAC section of: MembersPage/MarcellGal/EngineSwap/AirFeed for more info. on config I thought I'd cracked this. but I havent: I still can't get a stable idle without the engine racing. Hmmm. '''Config''' ||Idle cold||900|| ||Max cold idle temp||66|| ||Idle warm||800|| ||Min warm idle temp||75|| ||Idle afterstart RPM (added value?)||100|| ||Idle afterstart duration (s)||4.0|| ||IAC afterstart (steps per 160 rpm)||25|| ||Max steps to extend||250|| ||IAC step sequence||201|| ||stepper speed (ms)||2|| ||Idle control P||80|| ||Idle control I||10|| ||Idle control D||5|| ||Integral time speed||60|| ||Integral decrease limit||6|| ||Integral increase limit||25|| ||Integral deadband||10|| ||IAC deadband||10|| ||Seconds between overclosing||5|| Idle step bins: 220 (why so high??) when at 71.1 degrees (no point in including the rest of the table as it's a warm idle problem) The idle valve says it is at 80% on Megatune's display page, yet the idle still races at 1300 to 1400 RPM. I don't think there's a leak in the plenum, as that's all I can think of that would cause the problem. * Play with mdi.. where .. is the 2 hex digits from 00 to FF. * set back to mdi00 at the end for automatic control * set Integral decrease limit according to I value (though 06 sounds right) * Decrease the reference positions, a bit (like 5..10) higher above than the best mdi.. values (temp dependent). As high that still allows reaching target RPM, but does not allow much lower). Decreasing from a high value until RPM target reached is probably the easiest way. Do it for every temp as it warms up. '''Update''' A couple of problems were found. * The plenum did have a slight leak from an unused fitting. * I had a partially blocked pre-cat on one side of the engine (Main cat was OK) causing the revs to drop half the time!! * With the leak fixed and pre-cats removed, it idles smoothly but a little low. ** don't forget that the temperature dependent reference positions are just hint to the PID. The RPM target ("final word") depends on the (2 point, cold and warm) idle RPM points. * With the mapping tweaked a little bit usign the help above, it seems to work happily for warm idle. Just need to do the cold start now. [Post new settings]
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