Can anyone give me some info on iacv circuit meter readings? Like ohms out of the iacv itself, voltage to the valve from the harness at idle or key on only? It would be nice to have some reference points.

 

I'm troubleshooting a bad idle. Trying to figure out if it's the valve, or some issue with my harness. I can see that someone has done work on the harness before... If I turn my AC on, it idles better...

 

I read this thread and got some good info. I have the same issue. http://www.ultimatesubaru.org/forum/topic/145212-ea82-idle-issue-cyclic-idle/

 

 

 

 

Notice the larger and lighter colored wire routed to bypass the harness here

 

 

See it going into another plug? Someone ran this new wire to bypass the harness

 

Edited June 7, 20178 yr by TheGageinator

The FSM has the details. I don't have one here. The iacv should click, and you can see the valve move if you have it off the throttle body, if you apply 12v to it's coil.

 

I once had a car where the wire to the iacv coil broke inside the harness on the engine.

ill test the valve out and see if its working. i want to take the TB apart and give it a good cleaning, but im worried about being able to find replacement gaskets..

Either check with a dealer, or get some blank gasket material in advance, and cut your own. The little one for the valve is pretty simple. Just need to get similar thickness and rated for fuel contact.

I checked out the valve today. I have 12v at the connector when reading across the 2 terminals. When I first start the car, if I unplug the sensor, it will die immediately. After the car warms up for a minute, if I unplug it, there is no impact at all on the idle or the way it runs... Still bumpy idle

Measuring the voltage across the coil doesn't tell much.  The reading will be the same whether the coil is open or working.  The ohm reading for a good IACV coil is 8.6 to 10.6 ohms.  There should be open circuit from either pin to the body of the valve.  When the engine is cold, disconnecting the IACV coil connector will cause a large change in idle speed.  When hot, a smaller change.

Unplug what sensor?

 

The CTS can make for random idle and starting troubles.

The IACV I had fail open, caused the engine to not idle.  As soon as the throttle was released fully, it just shut off.  I could keep it idling by manually keeping the pedal down just a bit.

I meant when I unplug the iacv not sensor. Sorry what is the CTS?

 

I'll see what kind of resistance readings I get on the iacv.

Oh, ok, just wantwd to be sure.

The CTS is coolant temperature sensor. On the side of the thermostat housing, with 2 wires.

Iac measures 10.4ohms cold

The coil is ok then.  If it's on the car, you should hear a mechanical click if you momentarily apply 12 V to the coil.  If you have it off, you can see a plunger move when powered on & off.

Yup it seems like my iacv is good then. I was hoping this was my idle issue. Dang. There is a miss at most rpms. But the car has plenty of power. Going to do a smoke test on it tonight

Edited June 11, 20178 yr by TheGageinator

miss at most rpms....   Not an idle problem.

 

Once the throttle is open some, the IACV has little effect on running.

 

Verify all the plug wires are good.  They can be check with ohms also.  Also, running in the dark, look for arcs.  These are 2 different checks for different problems.

I think the misfire may be causing the idle to get worse. I did a smoke test last night, no leaks ill check ignition, compression and maybe fuel pressure today