Idle drop finetune

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PhoB
Posts:5
Joined:Fri Apr 01, 2016 9:16 pm
Idle drop finetune

Post by PhoB » Sun Apr 23, 2017 1:01 am

Hi, i would like to ask for your tricks or experience how to finetune idle control.
Main issue i have is idle drop under target after slight engine rev up. Most can be catched by activation DC additive, but activation triggering is limited logicaly minimum to over 1% tps. So there is a situation, where i can rev up engine even on 1% = still in idle control and after throttle closing is there a slight drop.
Issue is on cars with big throttle body and sligtly cammed engine.
I can be "fixed" by lowering maximum rpm for idle control, but it results in pulsing or rpm hangs afterstart when engine revs up itself over maximum rpm.
Its connected to RPM ref table and cranking DC. Maybe have these to able to corrected by CLT can help(correct ref table to resulting same values as normal DC ref , or crank duty lower to avoid large afterstart overshoot).
Did not try PID control yet, but assuming it will not help because triggering of the issue is the same.
Not using DC error table, it makes it worse. Also ignition control, but it can be slowered to make less harm and still used to smooth static idle.

How did you fighting with these?

RHD
Posts:537
Joined:Tue Oct 07, 2014 4:28 pm

Re: Idle drop finetune

Post by RHD » Sun Apr 23, 2017 6:54 am

we sometimes have similar problems with big ITBs 1% throttle still raises the idle a lot but you can adjust the TPS min voltage setting so that even a very small throttle movement increases from 0 to 1% and the idle control turns off, then you can use rpm ref to slow the rpm drop, you can also set the minimum and maximum idle valve DC in the settings so the idle will never go too low or too high. Sometimes it just takes some experimenting and testing. Try to get the target rpm to match the open loop rpm from ref dc during warm up before you try using the PID

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