My idle drops lower than it should sometimes, but then it will work the next day. Its clean inside but doesnt make the RPM jump much when re connected to the wiring harness, though you can hear the valve open.

I have re cleaned it, tested the IAC for continuity, and tested the leads from the wire harness for "battery voltage". It shows 1.8 V when the ignition is in the ON position, and nothing when the ignition is off. Should this be getting a full 12 volt battery current???

Traced the wires and it goes to the back drivers side of the engine bay and then down through the wall to the ECU. It showed 1.8 volts at the firewall as well. Is there any chance my ECU is not sending the valve enough juice?

One more thing. I had set the idle, reset the ECU, let it warm up until the fan came on and then took it for a drive and it was working perfectly, stopping at 1000 RPM and then setteling to about 700. I then turned my blowers (no AC) on at a stop light and my idle dropped to 500 and continued to drop to 500 for the rest of my drive.

What gives?

Thanks for the help...
sohc

 

uhmmm.....if your driving in stop and go 700 rpm is normal and 500 is normal at sitting dle.

 

But its not normal if I had set my base idle at 700.............

Anyone?

sohc

 

With the engine running, measure the voltage between the YEL/BLK wire and body ground. You should see battery voltage. If your not seeing battery voltage check for a short on the YEL/BLK wire between the IACV and the PGM-FI main relay.

The ECU does not send a signal to the IAC it grounds it. The YEL/BLK wire is a constant +12v source from main relay with the car running. The BLU/BLK wire is the ground wire that goes to terminal A9 of the ECU.

Side note. I've said this before. You shouldn't have to use the idle speed screw in the throttle body to adjust your idle. If you have to use that method that means that there is something else wrong with your intake air system. Could be anything from a clogged or dirty bypass port, PCV system, catalytic converter or a poorly running EGR system.


Modified by GhostAccord at 11:07 AM 9/14/2008

 

Thank you GhostAccord!

I appreciate the technical help... I'll post my fix if I in-fact needed one...

SOHC