Idle up and down!!!

[sbn1979]

Idle fluctuating badly, icv switched off to 999 steps, like the injectors are being switched off????

 

 

 

[Adamw]

I dont see too much ECU influence in your log.  The Evo stepper motors are pretty renown for short life/dying, have you tried any testing of the stepper motor?  Does the idle speed change at all when you change base position table?

[sbn1979]

So the icv does effect the idle but I found the fuel overrun settings to be cutting injectors which has sorted it partially, 

idle screws fully in and icv steps at 70, vehicle up to temp in open loop and it's still fluctuating 400 rpm, it's steady for about 15 seconds the then slowly starts to fluctuate till the point of cutting out

[Adamw]

Your log attached above showed no overrun fuel cut active so I dont see how that had any effect.

What happens when you unplug the stepper motor?

[sbn1979]

Yeah it improved when I switched the overrun off.

Still the same when the icv is unplugged and try use the BISS to set idle, just wondered if something in the file doing it?

[bsh]

Check that your ign angle is pretty steady@idle. Also check that your afr are pretty steady.

[cj]

I notice your fuel table slopes the wrong way in the regions where its doing the cyclic thing. 

@ high revs the fuel table drops, and at low revs the numbers are highers. Kind of looks like its cycling because it wants to idle at the high er revs based on throttle & spark, but doesnt have enough fuel so it leans right out then the revs start to drop, once its back in a roughly right a/f mixture the revs try to climb again to match your throttle opening.

 

Try adding 3 or 4 points to the fuel table around where it "peaks" at while doing the cyclic thing or smooth it out a bit manually so its a pretty consistent slope upwards as the revs/load increases

Edited August 10, 2017 by cj