$12P Idle MAP Threshold VS Idle RPM

[Dylan]

I have'nt made any changes yet just been logging. I'm thinking closed throttle VE could be worth a look as the MAP readings appear unstable.

[Jayme]

you sure you are using real vacuum and not ported vacuum designed for dizzies? what manifold are you running?

[delcowizzid]

turn the idle spark compensation off for a start IAC - Idle spark Adjustment params - IAC spark correct'n lower coolant threshold turn the temp right up.set idle spark advance all to the same value so as map reading goes up spark doesnt drop.i would also change the delay before using idle a/f ratio normally 25 seconds i set them at 0-2 seconds so its instantly at idle a/f ratio cause a 288 aint gonna idle at a commanded 14.7.flick me your bin if you want me to change a few settings round

[Dylan]

you sure you are using real vacuum and not ported vacuum designed for dizzies? what manifold are you running?

I'm running a Motec twin throttle body and the vac hose to the MAP is straight from the manifold.

[Dylan]

After Delcowizzid's suggestions there is an improvment!

I'm postig another log of after the changes.

[Holden202T]

i'd adjust the IAC so its not doing as much .... it looks like its on about 47 steps at idle, open the butterfly more to get it down, but make sure thats at warm idle 80 degrees or so - i try to aim for about 20 steps at warmed up idle ... but if you find it wants to stall a bit you can close it down to 10 or so, just means if the idle is too high it might not be able to bring it down, but i've found with my race car if i go to 20 steps i have almost stall issues sometimes but with 10 steps i don't because the butterfly is open enough to keep it going even if the IAC can't react in time.

also in my experience of big cams you want to have slightly richer than 14.7 at lower rpms, like up to 2000rpm say go 14 or 14.2 etc ... alot of it will be trial and error, but you'll get there in the end.

[delcowizzid]

looks heaps better now

[Dylan]

Yeah it definetely better! next job is work on a lower idle and also it's slow to return to idle so I will look at that next.

[Dylan]

i'd adjust the IAC so its not doing as much .... it looks like its on about 47 steps at idle, open the butterfly more to get it down, but make sure thats at warm idle 80 degrees or so - i try to aim for about 20 steps at warmed up idle ... but if you find it wants to stall a bit you can close it down to 10 or so, just means if the idle is too high it might not be able to bring it down, but i've found with my race car if i go to 20 steps i have almost stall issues sometimes but with 10 steps i don't because the butterfly is open enough to keep it going even if the IAC can't react in time.

also in my experience of big cams you want to have slightly richer than 14.7 at lower rpms, like up to 2000rpm say go 14 or 14.2 etc ... alot of it will be trial and error, but you'll get there in the end.

Thanks for looking, after delco's suggestions it's much better now. It's idling at 13.7 I think now with 30 degree timing.

[delcowizzid]

try playing with IAC - Transient IAC params - Throttle Crack Decay Rate to get it to pull steps out faster or you can limit the steps added with IAC - Throttle crack offset Vs RPM table and command less steps when you blip the throttle