Fast idle, open loop. Need help.

[phicho]

Fast idle at 1700 rpm. Scan tool says coolant temp 72 degrees-temp gauge says 150 to 160. I suspect that I have a bad temp sensor, am I on the right track? I don't find an IAC on the scan tool, it does have a Idle Air Mtr Pos that reads "175 steps". Loop status is "open". Throttle sensor ".54 volts." O2 sensor "792 mVolts", Mass Air Flow "9 gr/sec", knock sensor "0". z

 

[BRAD_PADGETT]

Fast idle at 1700 rpm. Scan tool says coolant temp 72 degrees-temp gauge says 150 to 160. I suspect that I have a bad temp sensor, am I on the right track? I don't find an IAC on the scan tool, it does have a Idle Air Mtr Pos that reads "175 steps". Loop status is "open". Throttle sensor ".54 volts." O2 sensor "792 mVolts", Mass Air Flow "9 gr/sec", knock sensor "0". z

I highly suspect that your Idle Air Meter reading is the IAC. Turn the IAC screw one quarter turn either clockwise or counter clockwise and see if the reading changes. The correct IAC s/b around 20-30 at idle in park. Read up on how to adjust the IAC. I have never run into a bad temp sensor before. I normally replace a part like this anyways due to the cars age. Brad

 

[alb84]

Temp sensor is the prob. change it out and leave the iac alone for now. It is reading cold, and adding fuel. The iac is just reacting to the extra fuel being added when the engine is actually warm. If it didn't the o2 would be 8-900mv. It is doing the best it can while being given bad info from that temp sensor. Hope that helps.
Danny