Wednesday, November 26, 2014

Basic idle settings

In order to start tuning we need to stabilize the idle, this is just basic settings in order to get us going.


Engine off:
1. Idle ignition
2. Idle fuel/AFR
3. Idle control setup
Engine on:
4. Idle valve test
Engine off:
5. Idle Cranking Duty
6. Idle Warmup Duty

Let's go...

Engine off:

Open your "Ignition Table 1 (Spark Advance)", your normal idle should be around 30kpa (no ac, no lights, no stereo etc...)

Set the idle cells at 14-16 - Read Rev1.1

Open your "Fuel VE Table 1" and set your idle cells with the same number (57 is good for me, your number maybe different to begin with)

Idle control basic settings:

Open "Startup/Idle" ---> "Idle Control"

Set it up like in the picture below:

Engine on:

"Batch Injection" cars will need to run idle a little rich even <14:1.
"Sequential Injection" can run 14.7:1.

Now start your engine and let it fully warm up, now check your AFR gauge, try to get the AFR that is right for your injection method and your engine.
If you are too lean use higher number in the fuel idle cells.
If you are too rich use lower number in the fuel idle cells.

When the idle is right (AFR) the engine will tell you, listen to it.

Now we need to test the idle valve range (gives air to the engine when throttle is closed)

Open "CAN bus/Testmodes" ---> "Output Test mode - Idle Valve"

Start the test at 0% and increase the % until rpm start raising - write the % you have found down.
Continue increasing the % until rpm will not raise any more - write the % you have found down.

Stop the test.

Engine off  !

In my car I found:
0% valve = 26
100% valve = 65

So my valve 0-100% range is 26-65, 26 is closed and 65 is fully open,

Now you can set up your "Idle Cranking Duty/Steps", how high you want the rpm in the first few seconds after engine started.
Usually you would want high when cold low when warn, but both of them should set the rpm around 1500rpm.

Every time you start your engine after you set up this curve, pay attention to the rpm, and adjust the curve to your liking.

Now we'll  setup the "Idle Warmup Duty/Steps" table.
Open "Startup/Idle" --->  "Idle Warmup Duty/Steps"

Here we set up how much valve (air,rpm) we want to add at a specific CLT temp, when cold we need more valve when hot we need less valve.

Every time you start your engine after you set up this curve, pay attention to the rpm, and adjust the curve to your liking.

Not too difficult, after we will finish tuning all the basics and the car will be running ok for some time we will take a shoot at Close Loop Idle (automated idle mechanism) .


  1. hello,

    thank you for your blog! really helpfull!


  2. Hi question I noticed when my IAT start getting hot like 90 degrees at idle like in traffic in the summer my idle likes to dip low and sometimes stall the car out. Any ideas?

  3. 1996 running MS2PNP, boosted with Project G Rotrex kit (C30-74).

    First, thanks for this write up! Great stuff and easy to follow with good explanations of what's happening. The reason I visited is because I couldn't get my car to start without some throttle input despite running very well and strong once about 10-20sec had elapsed (or I just took off and started driving). A fellow guy shared this with me.

    Your instructions helped and the car will now start easily without any throttle input. However, during the course of working through the instruction, I discovered some odd things:

    When I'm performing my idle valve test, I've found that it behaves inversely to your description. It will rev highest at 0 and begin to decline at about 16; if I keep increasing the value of the number, it will continue to drop the idle until it stalls. At 0 value it will idle at just over 2krpm.

    Also, and equally weirdly, when setting the idle warmup duty steps, I discovered that my graph needs to be inverted. As I push the line up the further it goes to the right, the lower the rpms go and the richer the AFR indication becomes. It seems to want to idle at my desired rpm with an indicated value of 10 AFR, and when I get it to about 13.5-14.2 it is idling at around 1200rpm.

    Does this, in your opinion, point to something literally being wired backwards? I'd guess the input/output to the IAT, but I'm not sure. It almost seems like it is giving negative voltage values but I'm not sure the MS logic would even work in that instance.

  4. Sounds like to IAC is wired backwards.
    But it does not matter really, if you set it all accordingly and it works - then it is ok.

    About AFR vs rpm - you should tune for 14.7 (or 13.5 if batch injection) at all time under idle.

    IAC = Air
    VE table = Fuel

    Tune for 14~ AFR and then start moving the IAC.

  5. Theres a setting to invert the IAC controls in TS. Cant remember off the top of my head where it is but its in the idle settings.

  6. Thanks. The car tends to like to idle a little rich and that isn't a problem (keeps it a little cooler here in TX), but I generally have it tuned at cruise to be around 14.7. Under heavy throttle as low as 10.

    I'll need to check the inversion settings; that could be it for sure. I seem to recall all that but... lots of settings... Easy enough to reverse the leads if required.

  7. I have the same issue, did it ever end up working correctly?