How to set your idle with Chrome (the proper way)

[Greg E]

I've walked you guys thru all the idle tables in this post (http://www.3sgto.org/tuning-engine-electronics-ecu-discussions/10777-chrome-v2-tech-manual.html#post211650) but it seems a lot of guys don't understand setting the idle. Those of you who experience RPM dips, on/off throttle stumbles, etc... know what I'm talking about. Though you can sometimes get away with setting the target idle RPMs, flashing then turning the key, there's an initial setup you have to go thru in order to ensure your car will idle properly.

This setup is actually taken out of the Mitsubishi manual (http://www.3swiki.org/Engine:_Adjust_Idle_Speed) for our cars. The process is exactly the same as any other Mitsubishi. This post applies to turbo and NA cars as well!


This is the procedure:

*Install NEW/Remanned throttle body
*Verify TPS is set properly and Idle Switch works
*Flash ECU with your target idle tables set to whatever desired idle RPMs you wish
*Drive the car until engine is completely warmed up
*With the engine still running, put the ECU into SAS mode (make sure your AC is OFF)
*Adjust BISS/SAS till engine idles at the RPM you want
*Disengage SAS mode



First off....

***Replace your throttle body!!!!

All our cars are approaching the 15+ year old mark. The throttle body is the crucial part of the engine which regulates idle and cruise operations. 90% of all issues come from sensor failures, clogged FIAV and leaking BISS and throttle plate screws. To compound the issue, nearly every car gets this oil muck saturated within the small chambers within the throttle body which impact airflow. I'd highly highly HIGHLY recommend you get it replaced with a NEW unit from mitsu, or contact April to get it rebuild. She does great work rebuilding our throttle bodies!!

http://www.3sgto.org/f62/throttle-bo...ice-10630.html

If you can afford $1500 for turbos, then you can afford to get your throttle boy rebuilt. Don't be cheap. ;)




Next....

After your new throttle body is installed, it's crucial that you don't have the throttle cable too tight. You can verify this by logging TPS with EVOScan. You should see values somewhere between 10% and 13% with your foot off the gas.

You also need to verify the idle switch is working with EVOScan (it's just a simple on/off). You see a value of 1 with your foot off the gas pedal, and a value of 0 with it slightly depressed.


Note: Some people are reporting that EVOScan isn't logging the idle switch correctly.

Verify this is what you're seeing in EVOScan:

http://i.imgur.com/CxC9qhi.jpg

If not, you'll need to edit that log value to match the screen shot (right click, edit data item....)




Next...

After you get your injectors scaled, your intake/fuel and timing maps tuned well enough to at least let the car start, run and drive, there's still a calibration that needs to be done with the BISS (also called the Speed Adjusting Screw) in the throttle body. This is what I'm talking about:

http://i.imgur.com/44gL6g7.jpg

Note: In this image the cover for the BISS is removed (usually it's missing on many cars).


SAS mode

If you recall in the chrome manual I talked about the idle timing stability control. The ISC will get the airflow in the right range for your desired idle RPM but it's ignition timing which is used to keep the idle at the desired speed. You've probably noticed that at idle, your timing values are always inconsistent and constantly jumping around. This is why.

When calibrating the BISS, the ECU has an input switch to disable this function along with the ISC all together so you can properly set your idle without the ECU trying to counter your adjustments. This is called SAS mode. There are 2 ways you can put the ECU into SAS mode. The first method is shown in the WIKI linked above. The second method (the easy way) is to use EVOScan.

Open up ECUFlash and the .bin file you flash to your ECU. Scroll down to the bottom and click on the Diagnostics tree, then Select MUT Actuator Mask:

http://i.imgur.com/YCWXcIK.jpg

These are a list of all the MUT commands I've found in the ECU. What these commands do is they manually activate switches on the ECU to test a function. In this case we are going to use MUT command C3 to put the ECU into SAS mode.


So start off by driving your car till the motor is completely warmed up, then pull over and let the motor idle. Open EVOScan and scroll down to the bottom.

Ever see this?

http://i.imgur.com/Xb9EpZK.jpg

If you enter in the MUT command into the Custom Request box, then check the repeat box, you will activate the switch. :) Very handy feature for testing solenoids/relays/fans to make sure they are working properly!

So you have your engine warmed up and idling what you need to do now is data log RPM. You can NOT use the stock Tach to set your idle. It's not accurate enough to tell you the exact engine RPM. Start your datalog and monitor your engine RPMs appearing on the screen.

In this case, we just want to put the ECU into SAS mode so you just type C3 into the Custom Request box then check repeat.

http://i.imgur.com/Ut3Ja87.jpg

As soon as you hit enter (with the logger still connected), you'll see some numbers appear in the Response box telling you SAS mode has engaged. You'll also notice your engine idle will change.

Now is when you pop your hood and adjust the BISS/SAS. A simple flat head screw driver will work just fine. Turning the screw clockwise will lower your idle and counter clockwise will raise it. You'll notice very suttle turns will make a HUGE difference in RPMs. Just a 1/16th of a turn can make as much as 100 RPM difference.

Stock these cars are setup for 650-700rpms at idle BUT you can make this any value you'd like. I typically go for 8 or 900rpms for better oil pressure and smoother idle with cams. Just remember to match the target idle RPM tables to whatever RPM you're trying to manually set it to in SAS mode!

http://i.imgur.com/1fhNYut.jpg

Once again, disregard the stock tach while you're setting the idle! Look at the RPM number you see in EVOScan!

After your idle is set, uncheck the Repeat box and delete C3 from the Custom Request box and the ECU will return out of SAS mode.

You will be absolutely amazed how much smoother your car will run now. :)

[Greg E]

Some other notes:

If you can't get the ECU into SAS mode with EVOScan you'll have to ground the brown connector located by the battery. Details are shown in the WIKI linked above


If your engine dies right away when you select SAS mode, you'll have to unselect it, open the BISS a few turns, restart the motor, then re-engage SAS mode. Your motor probably died from too low of an RPM. Opening the BISS will raise the idle enough for you to adjust. You will NOT be able to start the motor while the ECU is in SAS mode.

[tfw a-ok]

These directions are great, which means I have something else going on. Here is my sequence of events after replacing the throttle body with one of April's.

1. checked to make sure the throttle cable was loose (very loose)
2. drove the car to get coolant temps above 180*F
3. using evoscan through tactric connection set the ecu to SAS mode (idle dropped and car shut off) The BISS screw was barely open so i adjusted it
4. started car again and ran better but barely running so I began adjusting the BISS more to add rpm
5. was able to eventually get to my target RPM but it was not steady and fluctuated between 812, 843, 875 (target 844)
6. decided to leave it at that and release the SAS connection
7. car immediately began to idle around 1000 - 1200.
8. I drove the car home this way (.5 mile away) and investigated further.

Conclusion - something is out of whack! LOL and I'm not getting anywhere trying to figure it out.

Happy Mothers Day (to all mothers)

[Greg E]

You've got another X factor on your car (ProM) so I can't help but wonder if you need to turn down the low knob.

What are your narrowbands doing in SAS mode? Are you lean or rich?

[tfw a-ok]

Greg - You may be on to something with the ProM. I think the results "leaned" more lean than rich. Some how my wide band results aren't in the log but I sent it to you for review. Hopefully we can come up with something.

[Greg E]

Quick Note:


was able to eventually get to my target RPM but it was not steady and fluctuated between 812, 843, 875 (target 844)

This is normal. :)

[dbest671]

Hey Greg... Your BISS (Speed Adjustment Screw) reference... be careful because there is also a SAS screw on the throttle body, it controls how far the throttle plate closes, and shouldn't be messed with after it's set. If somebody does mess with that, you will need to adjust that first before setting the BISS and TPS. Procedure is loosen for the throttle plate to be completely closed *or until it's not touching the spring plate*, tighten until it touches the spring plate (the part where the throttle cable attaches to), and then tighten it an additional 1-1/4 turns.

[Greg E]

Oh that's right... I forgot about that other screw. Thanks for the reminder!

[Pensky3thousand]

Greg, no matter what I do my idle switch will not come on. My car idles at 850rpm where I set it but never drops below about 38-44 steps at idle. Brand new TB, new TPS, new IAC. I have tried everything. No other issues. No boost/Vac leaks. Everything else checks out. Starting to think it's not me and it's an issue w/ chrome or my ECU. I have about 4000 miles on the car already with the ecu but can't figure this one out for the life of me. Every engine related sensor on my car is new OEM.
I must say the fan control is amazing. My car runs at 186-192 even on warm days with a massive FMIC and a first gen stealth front end with out any ducting.

[Greg E]

Greg, no matter what I do my idle switch will not come on. My car idles at 850rpm where I set it but never drops below about 38-44 steps at idle. Brand new TB, new TPS, new IAC. I have tried everything. No other issues. No boost/Vac leaks. Everything else checks out. Starting to think it's not me and it's an issue w/ chrome or my ECU. I have about 4000 miles on the car already with the ecu but can't figure this one out for the life of me. Every engine related sensor on my car is new OEM.
I must say the fan control is amazing. My car runs at 186-192 even on warm days with a massive FMIC and a first gen stealth front end with out any ducting.

What does the idle switch have for a scaling in evoscan? I wonder if you are one of the unlucky guys who got the wrong evoscan XML file. I can email you the correct copy if you need it.

[Pensky3thousand]

What does the idle switch have for a scaling in evoscan? I wonder if you are one of the unlucky guys who got the wrong evoscan XML file. I can email you the correct copy if you need it.


Yeah, can you email me the xml file just to be sure I have the right one. My email is this username at g mail.
If it's a software glitch i'd be thrilled lol. Like I said I tested the IAC/TPS/TB themselves and their wiring. Everything checks out.
I'm stumped.

I'm going off the reading I get on my LCD boost controller. It always says idle switch: off

Idle switch always says "off" on evoscan as well.
I'll check the scaling for the idle switch on evoscan tomorrow.

Thanks for the help!!!

[iceorphen]

when youre logging via lcdbc you need to have proper LCD firmware. I had the same issue. blackstealth hosted a fixed file, no idea where its hosted now

[Kx1984]

my idle switch isnt reading as well i changed to match the pic you posted

also for those of us with q45 throttle bodies that dont have a BISS adjustment
i would assumem we just use the throttle plate adjusment screw?

on my evoscan i have isc counts in the 40's under my normal idle of about 1000(where i want it)
with the sas i have counts of 8 or 9 obviously because of sas mode and a idle of about 700-750

is there a normal isc count or not



Kx

[Greg E]

Look as the ISCV tables to see the "base" idle position values under all the various conditions.

If you're running a q45, you're probably not gonna have an idle switch

[Kx1984]

oh ill have to look into that

could have sworn it did
its a 4 wire tps and i thought the diagram said it did

Temp--------ISC
122----------60
170.6--------27
179.6--------17

so i guess im a little off

[Greg E]

I have never run a q45 so anything I got to say about it comes from others. It may or may not be accurate. ;)

[Pensky3thousand]

I got busy over the weekend getting down to Ray's to dyno but I finally checked on the scaling. Scaling is 1.

[tfw a-ok]

I actually had a series of other things going on.........

like having a broken pvc hose that went undetected until I decided to remove the crank vent.

Installed the throttle body gasket the wrong way (duh!) thanks April

Replaced the TPS but still had continuity on pins 3,4

I fixed all of those things so I'm now at a point where the car doesn't want to cut off when put in SAS mode and I was able to set my idle :Clap:


You've got another X factor on your car (ProM) so I can't help but wonder if you need to turn down the low knob.

What are your narrowbands doing in SAS mode? Are you lean or rich?

[Pensky3thousand]

bumppp

[MightyMouse]

I am confused by my car. My idle is seemingly perfect.. The car runs smooth at about 650-700rpm when warm.. But.. When I drive the car runs like dump.. feels bogged down or something, sputtering or missing almost.
Any idea where I should start?

The following are new:
tps, TB, coil packs, plugs, wires, ptu, knock sensor.
The CPS is still old, as is the IAC.. I am seeing a lot of timing advance (30 or so) on my car, but my car is also a 93 and I haven't fixed the timing maps yet.

Any help is appreciated.
Thanks.

[Greg E]

How are you seeing 30 deg of timing at idle??

[MightyMouse]

Sorry, the 30 or so is under light load..
here's idle.. (battery voltage is a bit low)
LogID LogEntryDate TPS RPM Battery TimingAdv
1 7/25/2013 12.54901961 781.25 11.87946 16
2 7/25/2013 12.54901961 781.25 12.02612 16
3 7/25/2013 12.54901961 750 12.02612 18
4 7/25/2013 12.54901961 750 12.02612 15
5 7/25/2013 12.54901961 781.25 12.31944 15
6 7/25/2013 12.54901961 781.25 11.80613 15
7 7/25/2013 12.54901961 812.5 12.31944 13
8 7/25/2013 12.54901961 781.25 11.95279 15
9 7/25/2013 12.54901961 781.25 12.39277 15

[MightyMouse]

And people are throwing around wrong info.. I was told (on the evoscan) my tps reading should be between 12 - 14..
So I'm now reading this and think I should adjust the TPS again.. make it closer to 10..

[MightyMouse]

Here's under the light load I'm talking about
LogID LogEntryDate TPS RPM Battery TimingAdv CoolantTemp AirFlow Air_Mass ISCSteps KnockSum KnockVoltage knock_base F_FuelTrim_Low F_FuelTrim_Mid F_FuelTrim_High F_O2FeedbackTrim R_FuelTrim_Low R_FuelTrim_Mid
354 7/25/2013 30.19607843 2625 12.39277 30 182.963 300 0.298828125 43 0 0.273 30 5.6640625 0.390625 0 11.328125 5.6640625 0.9765625
355 7/25/2013 12.54901961 3062.5 12.24611 34 182.963 181.25 0.1328125 43 0 0.5265 32 5.6640625 0.390625 0 10.3515625 5.6640625 0.9765625
356 7/25/2013 12.54901961 2937.5 12.39277 36 179.777 87.5 0.076171875 42 0 0.6435 34 5.6640625 0.390625 0 -2.5390625 5.6640625 0.9765625
357 7/25/2013 12.54901961 2718.75 12.24611 35 179.777 75 0.068359375 40 0 0.2145 35 5.6640625 0.390625 0 -2.5390625 5.6640625 0.9765625
358 7/25/2013 12.54901961 2531.25 12.68609 35 179.777 62.5 0.068359375 39 0 0.4095 31 5.6640625 0.390625 0 -2.5390625 5.6640625 0.9765625
359 7/25/2013 27.45098039 2312.5 12.61276 34 182.963 187.5 0.21875 37 0 0.624 30 5.6640625 0.390625 0 11.5234375 5.6640625 0.9765625
360 7/25/2013 32.94117647 2687.5 12.61276 26 182.963 375 0.34765625 38 0 0.6435 32 5.6640625 0.390625 0 10.546875 5.6640625 0.9765625
361 7/25/2013 32.94117647 3312.5 12.31944 26 179.777 456.25 0.34375 38 0 0.5655 40 5.6640625 0.390625 0 9.375 5.6640625 0.9765625
362 7/25/2013 14.90196078 3750 12.31944 38 179.777 187.5 0.130859375 41 0 0.507 51 5.6640625 0.390625 0 -2.5390625 5.6640625 0.9765625

[MightyMouse]

grumble grumble..
After going through your posts again I'm coming to realize all of these numbers look about right.. The exception being my TPS setting, since you've said it should be close to 10 I'll adjust that and take it for another dataloggin' drive I suppose..

[dbest671]

grumble grumble..
After going through your posts again I'm coming to realize all of these numbers look about right.. The exception being my TPS setting, since you've said it should be close to 10 I'll adjust that and take it for another dataloggin' drive I suppose..

Set your TPS the correct way per the manual.

[MightyMouse]

I know. I know.. :( I should have done that from the start..

[CoopKill]

Bumping it up! Cuz needs to be seen, that is all... :suspect:

[TUFFTR]

OK, so quick question guys. running 272's and a 3.5L. With the old aftermarket ECU it used to idle at 1000RPM no worries. I find I need to keep it around 1200 now as when the fans kick on and it dips down to 1000RPM. If I keep it at 1000, it dips down to 800RPM and if you feather the throttle to try and take off she stalls! WIll the above idle procedure hopefully fix this? I'm thinking of setting it to 1000RPM flat across the board for Target RPM AC OFF. Just wanted to confirm I dont need to adjust anything else while I'm there!

[Greg E]

You'll need to retune the base ISCV tables but that's just a matter of inputting the values you see in EVOScan into the tables.

[TUFFTR]

Bugger. OK, I'll read into that a bit more. I can only borrow the tactrix cable for a very short while so I need to make sure I nail this ASAP.

[TUFFTR]

You'll need to retune the base ISCV tables but that's just a matter of inputting the values you see in EVOScan into the tables.

Sorry to sound like such a novice, but which is the "Base ISCV" table you speak of?

[Greg E]

Sorry to sound like such a novice, but which is the "Base ISCV" table you speak of?

http://www.3sgto.org/tuning-engine-electronics-ecu-discussions/10777-chrome-v2-tech-manual.html#post211650

[TUFFTR]

After 6 months of not having my ECU, I now have it back, yay :D
Anyway, I don't have the $ right now for a tactrix so yet again borrowing one, now I have read the 'how to' idle section a few times now so I believe I should be fine in setting this up.
Questions were, Since running 272 cams in the 3.5L It's a bit of uncharted territory - I'm finding 950-1000 when warm is good.
I'm going to up all the values in the idle table by 300RPM to counter for this (as right now it's set at the stock 648 and I'm having ALLLL sorts of issues)
Do I; Need to adjust the AC ON idle table aswell to reflect the changes made to the Neutral Idle table?
And also, NO OTHER idle tables need to be changed even though I've made a quite drastic change to target RPM's?

[Chris@Rvengeperformance]

you may have to change the initial isc position. I would set the idle slightly faster (like 50 rpm) a/c on than a/c off. You may also have to open the biss screw up to center the isc.

[TUFFTR]

you may have to change the initial isc position. I would set the idle slightly faster (like 50 rpm) a/c on than a/c off. You may also have to open the biss screw up to center the isc.

Thanks mate. Noted on the idle position re: AC ON/OFFm 50rpm is a good starting point. The initial ISCV position perplexes me a tad, i.e, does it need to be a few steps more? few steps less? or does this process involve me changing it by say 5, flashing it on, starting the car, and seeing what it does? Or should I just note ISCV position and see how the idle goes after changing the target RPM tables? (Also, unrelated, and if someone can respond by PM that may be better, but any reason why it's triggering both Rad fans, not just the main one, is this normal for an NA ROM?)

Paul.

[Greg E]

Leave those tables alone for now. Adjust the target values, set the BISS via SAS mode, add a few degrees of timing in the upper right corner of the timing table if needed and it all should work.

[TUFFTR]

Leave those tables alone for now. Adjust the target values, set the BISS via SAS mode, add a few degrees of timing in the upper right corner of the timing table if needed and it all should work.

Cool mate. Thank you heaps! (Will report back after the weekend!)

[TUFFTR]

OK. I'm using the Chromed SL ROM. Bumped up Idle 300RPM for each cell (272's are a bitch) in the "Target Idle RPM (Neutral) table. Went though guide, up to temp, engaged SAS mode (although I dont actually think it engaged?) with the C3 switch, all I know is idle was hunting (1000>1200>1000>1200>1000>1200) and yeah, then she wouldn't start back up again.

If you'd like the logs please PM me so I can send them to you.
I just want to know, should I also change the "Target Idle RPM (Drive) field too?

[TUFFTR]

Put my log through MegaLog viewer and noticed the O2 oscillating like CRAZY from 0.0x to 0.95x every few milliseconds..
It's a brand new O2, is this what it's supposed to be doing? Gotta ind out why the bastard has started hunting :(

[Dougal]

Hi mate,
I found it noticeably changed idle sound when in SAS mode so you should notice a difference.
When I did mine I adjusted target idle rpm to what I was adjusting it to across the temp range.
Iirc the first three cells (for low temp) are at 1000rpm. I changed the other cells to be 900rpm. That way once I had finished adjusting the rpm via the biss screw and gone back into normal idle mode the ecu would target the same rpm as I had set when the car was in SAS mode.

Sent from my HUAWEI U8950N-51 using Tapatalk

[Dougal]

I'm fairly sure that there is a manual way of putting the car in SAS mode (grounding the timing adjustment plug pin?)
If you can't get the C3 request in evoscan to work.

Sent from my HUAWEI U8950N-51 using Tapatalk

[TUFFTR]

Thanks Dougal, all good mate. With the cams in it It needs to idle fairly high when warm, especially when the fans kick in it really soaks up RPM. I have been speaking to Merlin and he'll be helping me do a postal tune first to hopefully get this idle debacle sorted. Will report back over the weekend...

[TUFFTR]

Another quick one.
Would could be the cause of the car not going into SAS mode when either trying to trigger it through evoscan or EVEN grounding the brown connector at the firewall, no change at all!

[Dougal]

Its a long shot but have you got it enabled in the periphery bits in ecuflash?
Its normally set to enabled by default anyway but might pay to check.

Sent from my HUAWEI U8950N-51 using Tapatalk

[TUFFTR]

Hmmmmm. Looked through all the bits and I can't see anything that will turn it on or off.
Although I found I've got dual narrowband trim and EGR solenoid turned on...whoops.

[Dougal]

Sorry mate I gave you a bum steer there. My bad I was at work and not in front of my laptop.
C3 - SAS is part of the MUT actuator mask commands.

I may be wrong about this but there is an Idle control system test in ecu periphery2 bits but I dont know if that is for SAS or not. Besides if your not able to get it to SAS mode from grounding the jumper connector then something else is nit quite right.

ISC working ok? Got a spare you can try out?
TPS also ok?

Hope you sort this soon dude. Sounds like a pita.

Sent from my HUAWEI U8950N-51 using Tapatalk

[TUFFTR]

ISC is brand new mitsu, TPS should be a brand new unit within a week or so. I notice it also isn't hitting the idle trigger which may cause issues too!

[CoopKill]

Is your throttle cable too tight?

Sent from the Man Cave!

*\( ^o^ )/*

[TUFFTR]

Nein. It is not. Just an eeny bit of slack and you can see it slamming shut against the throttle stop. I might do some testing with TPS's off the car and just see if I can manually get them to hit the idle switch.

[Chris@Rvengeperformance]

Nein. It is not. Just an eeny bit of slack and you can see it slamming shut against the throttle stop. I might do some testing with TPS's off the car and just see if I can manually get them to hit the idle switch.

the default flag for the idle switch in evoscan is wrong, it always reads off. Search on here for the fix.

[TUFFTR]

the default flag for the idle switch in evoscan is wrong, it always reads off. Search on here for the fix.
You posted it not too long ago.
Thanks!
"The idle position switch in evoscan isn't set for our cars. Go to that line and set "x bit 128 to x bit 1"."