Idle control valve 20B
 

I was planning on connecting an idle control valve and running it from the Aux output on my LTX-12. I used a 13B plug which is the same fitment as the 20B idle valve. First attempt to set it up appears to render the valve fully open when the setting is switched on. Hence idle goes up silly high. The valve closes again just fine when you disable the setting. Is there something funny with the 20B idle control where by it is set up as normally open instead of normally closed and I need to change a setting somewhere in the Microtech I have not seen?

Thank you
Lee

As I recall, the aux outputs on the LT12 have a set purpose and you need to connect the idle valve to the correct output. "Aux output" on the white wire I think.

You'll also find the settings to control it under AuxAir.

If you get it running I'm curious as to how well it works for you.

I have it connected to the white wire.. That is right.. Just seems yo be set normally open.. Maybe I am not getting the settings right. Plan is to get a nice idle without and just have it there as a back up for pulling up rpms when stopping etc. And cold start help.

So your idle value is connected with one side to switched 12V, and the other side to the white wire?

Hi Aaron, yes I believe that is what the diagram shows. White being the aux output and a 12v I picked up in the engine bay.

Is your aux output set to something other than idle air? For example, set to trigger with temperature? The output can only have one setting at a time.

I don't think so but I will have to check. Will let you know what I find.
Cheers
Lee

Checked all my Aux Output setting as well and everything is switched off.. Looks like there are 4 values to be inputted for the idle control valve to work. Can you give me any starting values to use in case these are just completely wrong. Also do you set the RPM value to the value you want the idle valve to maintain or the value you want it to kick in at if it drops below the normal idle value set with the idle screw?

<a href="http://s157.photobucket.com/user/Leeroy_25/media/idle%20control_zpsslelv8c3.png.html" target="_blank"><img src="http://i157.photobucket.com/albums/t59/Leeroy_25/idle%20control_zpsslelv8c3.png" border="0" alt=" photo idle control_zpsslelv8c3.png"/></a>

Cheers
Lee

I have never used the idle air feature of the Microtech.

According to the manual at: http://microtechefi.com/download/ltmanual.pdf

AirMin and AirMax are the min and max opening times of the idle valve. Likely in mS though the docs have basically no info. I'd set min to about 20and max to about 100.

AirWat is the idle up when cold which follows a temp curve. The Microtech does the full amount at 11 degrees then tapers off until it reaches 68 degrees. Try 60.

AuxAirAFS opens the valve a bit after startup to create a startup high idle. It's an adder. Try 10.

AuxRPMSet sounds like it is the minimum idle speed you'd like.

All of those are guesses. The Microtech documentation for this feature sucks and since it was an optional feature, my ECU is not equipped. Then years ago when I sent it back to Microtech to be fitted with the feature, they send the ECU back saying it wasn't capable even though it is an LT8s which specifically says it can be enabled for idle control. At that point I began ignoring Microtech as a viable ECU option.

Anyway, you can't set up the idle control valve until the engine is tuned anyway so all this is academic right now.

Thanks for the info and yes I was going to do this at the end. I thought I was missing something in the manual. The details are very vague and no explanation on values to input. Will just have to play around I guess and see what happens!
Cheers
Lee

I am getting closer with the rest of my setup and want to try and give the idle control valve a go now.. Has any one used this that can confirm some good initial settings to start with please? To be fair I need to check what I have against what Aarron says above.. But there were a couple of questions in that where Aarron is not sure what the setting does. So to save me loosing a day trying and failing it would be great to get confirmation if anyone can help.
I basically get one shot at running the car a week if I am lucky and time seems to be going by quicker than I can count at the mo!

Thank you
Lee

Has anyone got any setting info to get the idle valve running with the LTX12 please. Suggestions above don't make sense with the values you can input which are between something like 0 and 12.12 I think. I think they may refer to vavle opening distance? Also not sure what actually turns the valve on or off as none of the values seem to have an off option? If it is rpm-set then it is on already and not doing a lot as this rpmset is currently set at 950rpm?
please help as I would like to get this going

Try the white /black wire thats aux air

Hey there, thanks for the reply.. I have it all wired up but I need an idea of what numbers to put in the settings for it on the ECU and which setting actually turns it on or off? Got any info for that please?

SO I played with this a bit today after getting the car setup much better.. does not seem to be doing anything although the valve seems to power up as you can feel it move when it is switched on? So first question. Is RPM_On what turns this function on or off or RPM set? if the latter I assume RPM_On should be set as off.
So correction to above info I believe other settings are as follows:

AirMin and AirMax are the min and max opening distances I think of the idle valve. mm I assume though the docs have basically no info and say time. range is 0-12.30 or something like that.

AirWat is the idle up when cold which follows a temp curve. The Microtech does the full amount at 11 degrees then tapers off until it reaches 68 degrees. Setting for this is stated in the manual as a distance and I am pretty sure you have the same range as above 0-12.30 hence thinking the above is distance and not time?

AuxAirAFS opens the valve a bit after startup to create a startup high idle. It's an adder. Try 10. same mm value 0-12.30

AuxRPMSet sounds like it is the minimum idle speed you'd like. I understand this to be the case.

So with RPM_On activated on any rpm value the IAC appears to open fully and give idle around 2250rpm. Changing any other settings has no impact.
Switch RPM_On off and move Airmin, Airmax, and Auxrpmset around seems to have no effect? There is also AuxpwmLOW and HI which I don't know if they do anything but changing them didn't seem to do anything. That said I think they are wastegate related looking at the manual?

Any pointers please?

Thank you
Lee

The RPM_on function is only used if the aux output is used to switch a load based on RPM (such as a shift light). If you turn RPM_On to On, it just sends a low signal to the valve, opening it fully.

Yes, I believe AuxPWM is only for boost control use.

It sounds as though AirMin and AirMax as you suggest are valve limits. So if the idle is way too high, decrease the AirMax.

I am pretty sure we tried that.. But if you turn RPM_ON Off then the IAC seems to do nothing. So i get the RPM_On is sending a trigger and hence opening the valve wise. So we know the valve works!
but then turn that off and set RPMset to say 1100 with engine speed at 1050 naturally. it appears you can move AirMin and AirMax where ever and nothing happens? There are basically 3 settings to play with and then AirWat and AFT for a bonus. i cannot see it should be that tricky!?
Could the valve not work other than when it gets a full voltage?
I don't see why you even need to put these values into the control. Surely you just tell it the idle to maintain and the valve should just open or close accordingly until the ecu reads that rpm form the engine? This just seems to complicate something for the user that should be very basic?
Can I test the ECU output somehow or test the IAC off the car maybe?

Thank you
Lee

It sounds as though your ECU isn't configured from the factory to enable the idle control function.

is there any way I can check? I assume I should read a voltage of some sort at the plug when I change the settings? It is all there in the software? I thought this was just a standard aux output option?

Microtechs need to be programmed from the factory to have these features enabled, unlike every other ECU where you just tell the output what you're using it for in software. At least the LT8 and LT10 were like this, so I have no reason to assume the LT12 isn't.

Probably the only way to tell is to enable the idle settings and check the output with a scope or meter that can read duty cycle. You'll see a pulse train that will vary based on how much the ECU tries to open the valve.

As far as I know, there is no way to find this out via the Microtech software. Which leads me to a minor story. 7 years ago I sent my LT8s to a well known Microtech dealer in Australia to have the idle control valve software upgrade fitted. I have a semi-early LT8s. That same LT8s that was promised to receive continuous software updates from Microtech. After waiting 3 months, I was told that my ECU was "too old" to have this upgrade fitted and they shipped it back to me. Via the slowest, cheapest postal method possible. This was also after I had modified my custom upper intake manifold for an idle valve. That was my last straw with Microtech.

Oh.. Bummer.. They don't seem to have great customer service that is for sure!! I will try and check the output again at some point. If idle stays as it was last time it was run up I may not need it.. it would be nice to have the option though!

idle valve
 

Aaron i want 2 tell you that i used your IAC settings that you suggested and they did worked on my 13B RE IAC.Car idles at 1100 rpms when cold and when is hot it does idle at 880rpms.You can hear the IAC activating and deactivating plus i disconnected it 2 make sure it was working and is indeed working.Hey Lee is me Jorge from facebook!

Hey Jorge, if you can share those settings with me on FB or here that would be great please. Mine is wired but I have not managed to get it to work yet. Gave up a while ago as really it seems fine without now. Just wonder if it might help with AFR or anything? For me my idle is rich now but happy. Also waiting to fit new plug leads which may help a touch if spark is better?

iac
 

Lee as soon as i am done playing with iac settings i will post them up.Like i said they did work but right know i am customizing them a little for my setup.

Hey Jorge, did you get anywhere with you IAC settings so that you can share them please? Still something I would like to try!

Thank you
Lee