So I just bought an 03 Evo8 and the idle was always around 600 rpm, then I replace the new valve that came with the car and the idle gets normal when cold starting, but it doesn't want to go below 1500 rpm and keeps trying to go over 2000 rpm even the car is fully warmed up. My question is that is it a faulty valve or does the idle needs to program somehow? Thanks for any help.

 

Can you swap the old one back on?

 

Already did, now it's back on 600 rpm routine, it is better than burning the gas for nothing

 

Have you tinkered with the BISS screw? Search for info on how to set it properly, could help.

 

what’s the best method to properly adjust the bias screw. I’ve seen where you go into evo scan and disactivate the iscv and adjust the bias screw till it matches the desired rpm. The other methods is to monitor the “iscv demand with ac off” and try to get it to 0v.

 

"iscv demand with ac off” is the best and most accurate way but it's not always an option in EvoScan. I haven't been able to figure out why it disappeared from my menu.

 

I believe 900 is normal for base idle fwiw

 

850 rpm

 

Do you mean that I should do it with the old valve on or the new one?

So for the old one, when I cold start it, it would go straight to 600 rpm, I assume a functional one should go around 1500?

For the new one, I am not sure that would help cause the new one has jumping idle not steady.