IACV (Idle Air Control Valve) Test

[REI600]

I'll check my TPS tonight and let you know which pins you need to be probing. If you are going from 5v -> 0v as your throttle increases, sounds like you're probing the wrong pins.

Try probing the pin you think is the 'signal' pin and earth (body, engine, - battery terminal, etc). You should see voltage increase as throttle opens (ignition needs to be on of course, and ensure your meter probes are in the correct hole for measuring voltage, otherwise you're going to have a bad day)

LoL going to have a bad day

I have ilustrated just up a bit which pins i have been testing on the TPS. Signal being pin 3 (earth probe (black lead)) and testing pins 2 and 4 against that with the positive (red lead). Thats how i got the readings i did.

If i am meant to be testing the signal (pin 3) with the positive lead (red) and earthing the black lead (body or battery...) been doing to SSOOOO wrong not testing the ohms of the live pin though.... i made sure i knew which that was,

I'd really appreciate that BCX. thanks mate. It'll be good to have something to compare what i got to Look forward to seeing hot it goes with yours.

 

[VOLK]

I setup the idle switch using the guides I posted a link to (involves using ohms to measure resistance/open circuit and feeler gauge between throttle stop screw and throttle arm so read that bit), then checked the idle tps value in mitsulogger using a cheap data logging cable. Mitsulogger is free and ftdi based obd2 to USB cables can be had cheap on ebay.

 

[REI600]

So. I found this video.

Amongt that talking of the how-tos, i was getting lost. Very lost. So i went hunting. And i found this video which i think helps a lot in explaining what and how to do it.

Seeing as it is not for the 6a13, the points being tested will be different and the finer details might be different too but, the mechanics of the test, would be largely the same.

From what i have read, the multi will be hooked to pins 2/4 and the earth (pin 3?) Or the actual earth (battery/chassis?).

Please, if there are corrections that i need to know about, please please please let me know.

I'll have the new ICV in my hot little hands soon so it'll be damn nice to have her purring again.... reliably.

Thanks in advance.

PS - Anyone know what size gauge do I use? Nothing on here mentions that.

 

[REI600]

This is what i am getting told from another mob. Seems a manual adjustment is not enough. I need to plug it in to the evoscan to adjust anything....

Any truth in this?

"The SAS screw is the BISS screw. You have to be in SAS Mode with a mitsubishi scan tool to adjust the BISS properly. Or..... Reset the battery by Unhooking it for 3 min... Restart car and start with the boss 1.5 turns out from fully down. Let car run for 15 min with no loads on at all like blower motor, radio, steering wheel needs to be straight ahead also.
After 15min...cycle key and restart the car turn all loads on and let idle for 3 min... Your idle relearn is reset after this time and you recycle the key.

The CTP or closed throttle position switch is located inside the tps on your car... Only way to adjust it is with a scan tool and reading volts for the tps. Fine tuning the tip in voltage and watching the CTP go from value 0 to value 1. If you don't have a good scan tool or Ecmlink... Then get a good obd2 mitsubishi logger from eBay. Enjoy."

 

[Guest]

This is what i am getting told from another mob. Seems a manual adjustment is not enough. I need to plug it in to the evoscan to adjust anything....

Any truth in this?

Not much...

The BISS is not the SAS. The BISS is on the front of the throttle body and might be under a little rubber cap but they have usually fallen out. It's also known as the idle adjustment screw.

You don't need a scan tool or Evoscan, however Evoscan is handy because you can disable the ISC in order to adjust the idle while the engine is running. Otherwise the ISC will keep trying to counteract your changes. If you don't have Evoscan, then you either need to unplug the ISC, or preferably turn off the engine, make an adjustment, then start the engine again and check the idle.

When letting the car warm up after an ECU reset it's important to leave the A/C switched on (it will come on by default) so that the ECU can learn the idle for when the A/C load is both on and off.

These are the steps for models without TCL.

1. Disconnect battery for 10 seconds to reset the ECU. Then leave the engine OFF.

2. Wind the BISS idle screw all the way in, then back it out 2 turns.

3. Loosen SAS screw lock nut, then adjust the screw until it's just touching the throttle lever. Then tighten it 1 further turn.

4. Tighten the SAS lock nut, making sure the SAS screw adjustment doesn't change.

5. Insert 0.65mm feeler gauge between SAS screw and throttle lever.

6. With TPS unplugged connect multimeter to pins 3 & 4 to check for idle switch continuity, when the connector is facing upwards it's the left 2 pins.

7. Loosen the TPS screws, rotate fully clockwise. Switch state should be ON.

8. Rotate TPS back counterclockwise until the idle switch just switches OFF, then tighten the screws.

9. Start engine and let fully warm up for about 10 mins in Neutral with handbrake on, leaving the A/C switched ON (important!).

10. When idle has settled and no longer dropping, check that it's around 650 +/- 50 RPM

11. If necessary, switch off engine and adjust BISS idle screw in or out (ISC will try to counteract your adjustment when engine is running).

12. Restart engine and check RPM. If not within spec then repeat from 11 until correct.

 

[REI600]

I cannot like this post enough.

Thank you heaps dude. Really, REALLY appreciate this.

 

[REI600]

Grab your multimeter, set it to resistance.
With ignition on, engine off and throttle closed, there should be resistance between pins 3 and 4. These pins are the idle switch.
When .65mm (manual, no traction control) or 1.4mm (auto, traction control) of feeler guage is placed between the SAS (speed adjusting screw) and the throttle stop, these pins should go open circuit.

VOLK - Mate... this is the issue i have. I have no prior experience with multimeters and, when you say "resistance between pins 3 and 4, in this situation, am i plugging the meter into the TPS itself or testing the plug? I am guessing the TPS itself but, i know if i do it wrong, things can go wrong wrong wrong for me.

EYEBALLPAWN -- Same situation here mate, the step by step guide you sent me saw me up to the multimeter testing point. At that point, i am not 100% on what i am testing and for the same reasons mentioned above, I'm not just going to "have a crack as it"

Unplugged and testing the sensor itself?

 

[Guest]

Unplugged and testing the sensor itself?

Power off, TPS unplugged and testing the pins on the TPS itself.

Hold the TPS with the connector facing upwards and try checking the left 2 pins, I think I've told you the wrong ones.

Anyway just probe the pins and see. It only took a few seconds to confirm which were the idle switch last time I set one up.

 

[REI600]

So, Test is done and some adjustments made. The idle is sitting steady @ around 650-700. so thats about right. I tested the early rev range (which is where the problem was/is) and it wasnt there yesterday when the test was done. The car is known to be "funny like that" so, i will keep testing and keep moving forward.

On the upside, i am getting quite adept at removing the intake piping

One thing it is doing now though is If I free rev it (searching for that point where it dies), at around 3000rpm, it cuts revs... this happens only if I rev the engine up gradually. If I give her a stab, she get over that rev with no worries at all.

Is there an inbuilt safety something that might cause this to happen or, is there still as issue with how I have done the TPS tune?

Thanks to all the guys who helped me get through the throttle tune. Really appreciate it. It might have made all the difference. The new IAC and the Evo 8 MR BOV have turned up so I will be fitting them in the next day or so... pretty damn excited about that. Should be awesome!!

Again, Thanks HEAPS guys!!!

 

[VOLK]

VOLK - Mate... this is the issue i have. I have no prior experience with multimeters and, when you say "resistance between pins 3 and 4, in this situation, am i plugging the meter into the TPS itself or testing the plug? I am guessing the TPS itself

Correct, test the tps as that's where the idle switch is. There's infinite info about using multimeters online. YouTube will show you how to test resistance/open circuit.