808 ECM with 12p on a sc v6 with cam idle issue

[dmac_25]

Hey guys just want to touch base and see if anyone has had any issues like this.

Bit of background on the car running a VN 808 with 12p on 2bar map sensor. Engine is a sc v6 m90 blower with a comp cam and a air to air intercooler kit.

I have a ECM setup with the nvram board that I use for tuning so I got the car all tuned and happy idling at around 1100-1200 rpm with tweaking the idle tables tweaking the throttle stop and playing around with hole size in the throttle body. Because of the air to air ic the lag time for iac motor to react to what the engine wants under 1000rpm plus the cam all made tuning the idle a real pain but got it happy in the end.

Now I pulled the tune off the nvram burn it onto a chip into the stock memcal put the memcal back in the ecu for the car and the car now won't idle below 1500rpm no other change but swaping the ECM and burning a tune.

Any little tips would be great and much appreciated.

Cheers

[antus]

It sounds like you may have been tuning with the regular block learn functionality turned on, and when you unplugged the ecu it forgot what it had learnt. If this is the case then your tune isnt as close as you thought.

If you want to turn of block learn while sorting it out set "BLM Params - Block Learn LOW temp limit" to the maximum, and put it back to 80 degrees when you are done.

[VL400]

And there are idle learning things at play for IAC steps too, these are stored in the ECU RAM also. Will need to reset the ECU and then have it then re-learn them. If you logged the IAC steps before and after changing to the other ECU they are going to be different.

[ejukated]

you should be able to idle under 1000rpm once all the settings are sorted, it doesn't take much to get it to idle stable once the TB is setup

[dmac_25]

Thanks Antus I have the car back again finally and I will turn off the block learn function and fiddle with the tune again.

Vl400 are you suggesting once I Reburn the new tune into the correct PCM then to reset it after I have burnt the chip and fitted it??

Ejukated it is just not physically possible to get this to idle sub 1000rpm with how it's setup right now. The car has a fair decent comp camp then add the blower and then add the air to air intercooler setup. By the time iac moves and the engine reacts and the PCM then readjusts the iac in the lower revs it just hunts from around 600rpm to 1300rpm with it always trying to catch itself

[Dylan]

Have you tried closed throttle 'VE? Made HUGE difference to my V8 with large cam and little vaccum.

[delcowizzid]

and turn off IPS spark it makes them hunt bad with a cam but setup right you could rely on it to hold idle more than the iac

[Jayme]

ive had fun trying to get cammed l67 to idle without hunting... ips spark off and get fuelling perfect at idle seems to help a lot, but its more fucking around than normal... and a stuffed spark plug and the hunt comes straight back ...

[Holden202T]

yeah changing things can make a hugew difference, my brothers stock v6 never had any issues hunting until the turbo went on, then it was way harder to get the idle right!

[Dylan]

What afr are you getting and aiming for?