basically the same as car in sig... I have a code 24 (air control valve) and 42 (idle switch error). I have replaced the IAC 3 times with used, but good ones. This last time I replaced the upper portion of the throttle body as well (part that the IAC attaches to), out of a good car. My timing is at 18* instead of 20*, but that shouldn't cause this. I haven't been able to check the wire harness, but I suppose that could be my issue? What are the chances of it being the CPU? 

 

Symptoms: low / rough idle on cold startup, will die if you push the gas before it warms up, runs really rich on start, begins idle at 500 and warms up to 1500 but sometimes it will idle down to 1000. I can't get it to idle at 750.

I have not battled with those codes.  But I have found a broken wire in the engine harness a couple times.  One was rubbed through the insulation and shorting out.  On the wire was broken inside the insulation, and intermittent.

 

I had the ECU temperature sensor fail recently - caused all kinds of weird problems - idle speed all over the place.  Wouldn't run when cold.  Did not get a trouble code.  It gradually got worse over time.

Injectors clean?

SPFI or MPFI?

A dirty TPS also caused issues with my EJ22 with start and running issues.

Cheers

Bennie

SPFI, injector looks brand new. When it's running and warm, it will idle at 1500, but the power band is nice and smooth even with the timing discrepancy. 

perhaps the temperature sensor ?

I suppose I could try that. I have a couple I grabbed from pnp last time I was there.

I suppose I could try that. I have a couple I grabbed from pnp last time I was there.

I have a rough all over the place unpredictable idle. Usually from 1500-3000. Car sometimes bogs out , when clutch is released after stopping at a light. Checked the idle air control valve, but electrically was within the parameters. Any ideas on where to go from here?

                                                                                                                               Sask49

Check the ECU thermometer.  It is the 2 wire sensor below and front from the thermostat.

Hello,

 

My son is having the same problem.  So reading through these issues I just reached down on the harness where it goes along the intake and lifted it a hair.  Killed the motor.  So I stripped off the loom and guess what........  Just like the above said.

 

Thanks Again,

 

Eric

Hello,

 

My son is having the same problem.  So reading through these issues I just reached down on the harness where it goes along the intake and lifted it a hair.  Killed the motor.  So I stripped off the loom and guess what........  Just like the above said.

 

Thanks Again,

 

Eric

 

so you're saying a broken wire or shorted wire???

Hello,

 

On my Son's car it was an intermittent open.  I removed the flex loom and started tugging on individual wires and it fell apart.  So to answer your question it was a broken wire or in our case it was 2.

 

Thanks,

 

Eric

Injector looking clean doesn't necessarily mean it's flowing as it should be

Cheers

Bennie

Update: Injector is working properly. I found a broken/shorted wire in the harness for the IAC, but fixing that wire did not help the issue. I moved on and fixed an exhaust leak at the header where the gasket was blown out and Boom, the issue was fixed. Now I still have an idle issue, but it doesn't throw the light on. With the green plugs connected, I get a code 42 (idle valve or something) and my car won't idle below 2k rpms. Idle is nice and smooth, car has good power, and seems to run fine other than the constant high idle...

Edited January 7, 201511 yr by The FNG

Here's 2 similar things I've had happen with EA82s -

 

IAC solenoid died.  The engine would just shut down unless I held the gas pedal part way down.

 

The ECU thermometer went wacko, and in the end, was telling the ECU that the engine was cold all the time, so the car idled at high idle all the time.

 

I don't remember if I got a code for the IAC failure.  I did NOT get a trouble code for the thermometer, as the readings were not outside of the possible range of valid readings.