Iac reading on atap and questions
Iac reading on atap and questions Ok my iac reading on atap shows zero and always stays at zero at all throttle positions. The desired iac reading is usually between 15-70 all the time. is zero fully open? and if its always at zero at all throttle positions does that mean my iac is bad? I don't have any codes just kind of rough running, but thats probably because of my 2 step colder plugs and narrow spark gap not to mention im using cheapy champion plugs. But my main question is if my iac is bad
Zero reporting from IAC means the system is shut. You could possibly have a vacuum leak or the throttle blade is open too much. Check TPS % open. At idle in park, the TPS should be 0%. If the ttl blade is open at all, the PCM switches to a different fuel cell and the engine will run rough. Sometimes drilling too big a hole in the ttl blade can cause the IACs to go zero. I'm not sure why your IACs don't change during TPS changes. Usually a problem with the IAC system triggers a code.
Richard
Richard
ok well the throttle blade is closed and atap is reading the throttle position as zero.. the iac stays at zero also no matter what throttle position... the tb that is on the truck is one i got used..the iac looked like it had corrosion and it was all gummy. i cleanse the iac and installed the tb and got a ses light right away but the light went away after reseting the comp and it never came back. i still have the tb that was stock on the car which is in perfect working condition so i guess i will just remove the iac from the known good one and put it on mine and see if the readings change at all
TECH Senior Member
Joined: Nov 2001
Posts: 9,246
Likes: 3
From: Troy, AL
If you have no DTC and your IAC pos doesn't attempt to follow the disired IAC pos, then your version of Autotap isn't supporting this parameter for some reason. If your IAC were truly at zero all the time, you'd know it by the way the idle speed would change with engine temperature and you would get an SES light.
