Clicking from TB= bad ISC?

[lil corb]

First I'm not recirculating, before it would idle surge a little and then idle steady at 750rpm. Recently I hear a loud clicking noise coming from back side of TB right around ISC and it idle surges constantly and the idle holds steady at 2000rpms at stoplight. Bad ISC? or maybe Idle Speed Switch?

 

[Old Mitsu Tech]

The isc is a stepper motor type of setup. You can lose a winding in the isc, or you can lose a drive circuit in the pcm. Both are likely and if the isc would ground out, it most likely would take the drivers in the pcm with it. Either way you wind up with bad idling which is not controlled. You can refer to your fsm to find the resistance specs of the isc. If it's in spec then most likely idle stop switch or the pcm. If it's out of spec, there you are. You found it.

Good Luck

 

[blueman803]

Pop the hood and let someone else turn your car on but do not start it. Listen to see if there is any clicking noise under the hood. If there is disconnect the ISC. If there is no noise after disconnecting it your ISC is probably shot. It happened to me. Somehow mine passed the ohms test but was still bad.

 

[lil corb]

Pop the hood and let someone else turn your car on but do not start it. Listen to see if there is any clicking noise under the hood. If there is disconnect the ISC. If there is no noise after disconnecting it your ISC is probably shot. It happened to me. Somehow mine passed the ohms test but was still bad.

I will try that tomorrow. I started the car up earlier and disconnected the ISC and the clicking got louder and somewhat to a minor knocking sound. any ideas?

 

[lil corb]

Also how could I test to see if the Idle Speed Sensor is faulty?

thanks