Idle screw adjustment

[bmwguy325is]

Has anyone out there with a custom tune or after market ECU or MAF swap ever had to adjust the idle stop screw to obtain a normal warm idle?

[jlevie]

This really depends on what has been changed in the engine management system. A non-OE tune should not require adjustment of the idle stop screw if the TPS is good. In a like manner a change of the AFM should make no difference, if the AFM replacement matches up to the engine management system. But if you change the DME to something else all bets are off.

[bmwguy325is]

I changed to a Miller 3 inch MAF. The car refuses to idle at the correct value. The TPS does work. I did the ohm meter tests. If I load a map into the ECU that is for a stock car it idles at the right RPM. The next thing someone said to do was adjust the idle stop.

[bmwguy325is]

Ugh I hate this high idle. Though take offs from a light are way easy....:neutral:

[jlevie]

I changed to a Miller 3 inch MAF. The car refuses to idle at the correct value. The TPS does work. I did the ohm meter tests. If I load a map into the ECU that is for a stock car it idles at the right RPM. The next thing someone said to do was adjust the idle stop.

I suspect it isn't the problem, but make sure that the idle switch in the TPS is operating. Hearing the click isn't proof, you have to check it with a meter or test light.

With the engine at normal operating temperature, disconnect the ICV and adjust the stop screw for an idle of 950rpm. Then adjust the TPS so that the idle switch closes when the throttle arm is 0.030-0.060" off the stop screw. When you reconnect the ICV the idle should stabilize at 750rpm. If idle is higher than that, I'd look for intake leaks first.

[ROLLingKING]

dang bmyguy325is. it seems that miller 3in maf is a little more tricky than plug and play like they make it sound. Have you tried calling them and telling them all the other mods you have. I wish i could help. I just ordered my miller MAF!

[bmwguy325is]

It might just be my car with the idle problem. Yes ive called. In there defense the tune they gave me is for a m30 throttle.

[carfantiti]

did it do it before you did miller?
if no than no its not just your car.

[bmwguy325is]

I suspect it isn't the problem, but make sure that the idle switch in the TPS is operating. Hearing the click isn't proof, you have to check it with a meter or test light.

With the engine at normal operating temperature, disconnect the ICV and adjust the stop screw for an idle of 950rpm. Then adjust the TPS so that the idle switch closes when the throttle arm is 0.030-0.060" off the stop screw. When you reconnect the ICV the idle should stabilize at 750rpm. If idle is higher than that, I'd look for intake leaks first.

Thanks I will try this. I know the ICV can only do so much.