Runn

Like the topic says... Anyone know?

Shallow Bay

iTrader: (3)

Mine has always been around .75 volts.

Runn

ok, thanks.

LS1-450

iTrader: (33)

Check the voltage w/ butterfly plate full open, 90 degrees. The voltage should be 4.71 volts max.. Most keep it under 4.70, just to be safe. Anything more than 4.71 @ WOT can trigger a check engine PCM code. If I remember corrrectly, engine off no idle is in the .46-.50 range when 90 degrees open (WOT) is @ 4.69 volts. My car idles w/ the throttle palte closed, through the idle adjust vent @.46-.50 & throws map codes above .80 @ idle. Hope this helps.

Runn

Thanks for the great answer.

My idle is 0.60volts now and my idle is a little high, I´l lower it to .50 and see what happens.

LS1-450

iTrader: (33)

Keep in mind that engine idle speed is programmed by the PCM & the TPS sensor is a reference to the PCM. Lowering to .50v may not change anything unless your previous idle rpm was lower than it is now.

My PCM is programmed to idle @ 750 RPM in park & 700 RPM in gear (A4). If you have an A4, your car is going to try to idle @ the speed programmed into the PCM. One thing that you may try is to allow your car to re-learn the idle speed. Once you check that 90 degrees is as close to 4.71 volts as you dare to go, check the closed position. If it's .50v, then Ok. So long as it isn't above .8v or any voltage that triggers a check engine light @ idle.

Disconnect the battery for an hour or more. Re-connect & start the car (you may have to assist w/ the gas pedal to get it idling for the first minute). For an A4, idle in park for 5 minutes & then shift to drive (foot on brake) for 5 minutes. Then, shift back to park & idle for 5 minutes w/AC on high. Leave AC on high & shift to drive for another 5 minutes. Your car should now hold a steady idle. I'm not sure how the idle is programmed in the PCM for an M6, but, if you have an M6, a re-learn could also be worth a try. I'd do the same as above w/ the battery & then, start the car in neutral & idle for 5 minutes, then w/ AC on for another 5 minutes. Turn AC off & see how she idles.

Runn

The problem is that my IAC is down to 0 and my idle is still high and the tb-blade sticks at idle position. I have no airleaks... maybe its my iac that has given up.

nomadnate

iTrader: (1)

try cleaning the throttle body it can keep it from closing all the way

LS1-450

iTrader: (33)

Ok, so the problem is that with the throttle plate closed, the IAC is also completely closed @ idle or is the signal @ the IAC 0 volts & in an open postion that's allowing too much air to pass? I think you are saying that the IAC is completely closed. Does your throttle plate have a hole drilled into it?

The IAC should find a happy place, once the idle settles down, & will adjust based on air, throttle position,...etc.. If you are saying that the IAC is closed & the throttle plate is closed completely, then either there is a hole drilled into the throttle plate or there is a vacuum leak. The most common HIDDEN vacuum leaks are @ the connectors on the rear of the intake manifold, under the intake manifold where the gasket seals a runner, the intake manifold bottom cover, or a fuel injector "o"-ring. More findable vacuum leaks could be @ the oil filler neck, PCV, EGR tube (if equipped), behind the throttle body, anywhere inline after the MAF, brake booster line, cruise control line...etc..

Also, the throttle plate shouldn't stick shut. Adjust the idle screw so that it breaks away from the closed position without jerking or sticking.