idle help

[lekonna]

All-right, i've been having this problem for a while now:

i cant seem to get my idle to work without it oscillating like hell on closed loop.

the problem is that i have fair amount of compression and very light drive drain, this means

that the normal ignition that i have setup under 2000rpm, the engine wants to keep the revs

high. So when i close the throttle, the revs hang high.

Normally this would tell me that there is a leak in the system somewhere where the engine gets

air pass the throttle body that keeps the revs up, but this is not the case. i think its coming

through the idle valve which is connected to the pressure side of pipes after the turbo.

The idle valve is bosch 3-wire one.

I've even made an ignition overlay map to drop the ignition angle when the TP is 0% to stop

the revs from hanging.

the idle ignition hits only at under 25kph speed, so if i want to coast to traffic lights with

the car on neutral it will do the bouncy-bouncy thing until i get into range of the idle control.

With setting the idle ignition control on, i can get the ignition to stay relatively close to the

target with a somewhat smooth idle. The problem is that since the air temp variations here

in finland are so huge, it means that in the morning i'm idling at 1100 rpm and in the evening

when the air is hot i'm stalling the engine. The stepper control for the idle on open loop does

not have option to take into account the IAT temp which would help _ a lot _.

If i turn on the closed loop control, the idle ignition and the closed loop control will fight each

other and result in the oscillating idle, it sucks ass.

Is there a way to make the closed loop idle control so slow that the fine grained control would

be handled by the ign control and the closed loop would just slowly find the correct stepper position?

its tricky to adjust since slight modifications make a big difference, the thing revs like a motorcycle :/

here is my current map as attachment. i've updated the ecu firmware after this point if it makes

any difference.

I can take some logs of the idle behaviour, try various things ect. just please help me

-j

konnan2jz_paskaa.pcl

[Thom]

Hi,

What model of Bosch 3-wire solenoid do you use?

On my car I use the old Porsche style unit, which allows for a very good finesse of adjustment.

It is running in closed loop, with PID all zero'd as they have never needed to be adjusted.

I did have the problem with the RPM staying "high", above 1600 rpm, when closing the throttle (with the car still moving and dpressing the clutch), but solved it by reducing the Speed lockout to a very low value (3 km/h). What happens if you try a value lower than 25 for the Speed Lock Out?

Engine CR is 8:1

Then on another car I still have the same problem with the engine speed not going back to idle level when closing the throttle with the car still moving. If I'm in overrun mode (TPS 0%) then depress the clutch to let the engine go down to idle speed, it will keep running at 2k rpm until I blip the throttle again, after which it will run down to idle speed. That is using a 4-wire stepper motor. Idle is running in Open Loop as PID idle settings don't seem to have any kind of effect whatsoever over the Open Loop mode. I suspect faulty grounds and/or a stepper motor that is not reactive enough.

Engine CR is 11:1

[07_wrex]

I don't have any useful info for you, but I have a similar problem. Idle fluctuation when the air temp changes. And not really drastic changes either. I'm getting tired of hauling the laptop around to make changes to the idle. The available adjustment tables for idle control are great, but it seems it's not enough sometimes.