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*How to setup idle for AEM ECU*

 
Old Mar 30, 2011, 07:17 PM
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Lightbulb *How to setup idle for AEM ECU*

So after a few years of tuning the aem i believe i have finnally figured out how to get the idle to stay consistant. I know alot of the self tuners out there like me have been having problems for a while now. Lets see if this can fix them. I have already tested this on my evo 8 and a friends K24 honda which had similar inconsistant idle issues. Fixed both. Its all about finding the sweet spot. I'm going to start from the basics of how to setup idle with aempro so everyone can follow and understand. For those of you that cant get the car to idle at all see this thread first.....
http://forum.aempower.com/forum/inde...c,13376.0.html

First thing that needs to be done is turn the 02 feedback off. Open Idle/Idle target base table/Table. This is where you will set the desired idle rpm.
Lets start with these settings.

-40 to 68=1400rpm
86=1350rpm
104=1325rpm
122=1300rpm
140=1250rpm
158 to 248=1200
This will give a 1200rpm idle when the engine is warm. 158F+ ECT and 1400 when cold -68F ECT.

Get the car started and idleing somewhat steady. You may have to baby it until you can get it to steady out from the idle feedback working. open idle templates.

You may have an Idle Learned value of +/- 5. This is normal at this point. Adjust the fuel table until you can at least keep the AFR in the 14's when the engine is at full temp. At this point the idle should be around 1200rpm. Monitor the idle learned value,Adjust the Idle% vs Target graph/table at the 1200rpm point up if the feedback is negative or down if the feedback is positive. Adjust unitl the feedback value is staying around 0. Now, go back to Idle/Idle target base table/Table. Change the 158 to 248 value to 1300rpm. The engine should idle up, give is a few seconds to stablize. Adjust the Idle% vs Target graph/table at the at the 1300rpm point until it is around 0. Do this all the way up to 1600rpm adjusting the idle% at every rpm point so that at all commanded rpm points the idle feedback is around 0. Change the commanded idle (Idle/Idle target base table/Table) to 1100 rpm if it can idle somwhat stable adjust the Idle% until you have near 0 feedback (idle feedback value). Do this at 1000rpm,900rpm,ect. or until you reach an rpm where the engine wont idle. Once this is done you will be able to see the "curve" of the Idle% vs Target graph. Take the rpms point the engine would not idle at and smooth them making the table have a consistant curve. example: 1000rpm=35% 900rpm=33% 800rpm=30% an so on.
Also, adjust the 1700rpm-1800rpm the same way. Make 1900rpm and up all the same % making the curve go flat at 1900rpm-3000rpm.

Now set the idle base back to 1200rpm. At this point the engine should be idleing fairly well. Turn the engine off. Start with these values.
High idle car speed=255
High idle rpm offset=0
High idle wait time=0
Idle off if tp over=2%
Idle on if tp less=2%
Idle feedback above rpm=400rpm
Idle feedback below rpm=1800rpm
Idle a/c load comp=5% This may need to be moved up or down if the idle feedback has excessive values. ie:greater then 4%
A/c on delay=1 S

Go to Configure/ECU setup/Set throttle range. Follow the instructions to setup
the TPS.This is where it gets tricky!!!!!!!!! You should now have a tps reading of 0.
Go to Setup/Sensors/Throttle position sensor/Options. Monitor the throttle % and move the TPS min. voltage down in .02 increments until the throttle % shows around .5% Example: 0.70 / 0.68 /0.66,ECT. If the throttle % EVER shows 0 some of the idle tables will be turned off!!This is a problem with the software imo and took me years to figure out. The throttle % will change from when the engine is cold to when it is warm. The trick is to never let the Throttle % read 0. If it does the idle goes all to hell. At the same time throttle %must never be above the
2%. Watch it during cold start and when the engine is hot, adjust accordingly to keep is between .5-2%

Go to the Ignition table and set the all the cells near the where the car is idling to 10 degrees. So below 1500rpm and -5psi will be 10's.... Open Idle/ Advanced idle/Templates change these values.
Idle park target=48%
Idle feedback minimum= -5%
Idle feedback maximum= 5%
Idle feedback rate= 588
Idle extra <12 volt= 0

Open Idle/Advanced idle/Ign vs idle rpm table/Table Use these values.
-325 to -125= 10
-100=9.84
-75=8.44
-50=6.33
-25=4.22
0= 0
25= -3.52
50= -5.98
75= -6.68
100 to 300= -8

note: Im not sure if all of the above settings will work for evo 9. Someone will have to test them out.

If you reopen the Ign vs idle rpm graph you will notice is has some steep curves now. This is what makes the engine idle at a steady rpm. The base ignition timing
is now 10 degrees but when the engine idles up it will retard timing and idles down it will advance the timing. This way the ignition timing can control the idle rpm instead of just using the iac motor. This gives a great idle. A/c on, hot, cold high,low,turning, everything. This also fixes some cold start issues. If the engine goes to stall the timing will ramp up and rev the engine back up before it stalls.
this reaction happens MUCH faster then the iac motor could ever respond.

Start the engine and let the idle settle, you should notice the ignition timing moving around alot. More with big cams i would think. Mine moves from 2-18 degrees at idle. But now you should have a rock solid 1200rpm idle.
Go back to the idle target table and move the 150F-248F to 1100 rpm and see how it idles also making sure the idle feedback is near 0.
-3 to +2 is ok. It will be best if you can keep it between 0&-2 as it will encourage a higher idle before the feedback responds.
Now try 1000rpm. 900rpm,ect unitl you find the sweet spot that your happy with.
With big cams i wouldnt go lower than 1000rpm. Mine will idle at 800rpm but its very rough and shaking the car. 1050rpm feels good on my car.
Now open the 02 feedback table and set the idle & drivability area's to 14.7AFR and turn the 02 feedback on.

I hope this helps all you self tuners out there like me.

Last edited by browningderek; Jun 23, 2011 at 04:20 PM.
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Old Mar 30, 2011, 07:57 PM
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Thanks for all the great information. I will definitely have to give this a shot when I bring the Evo out of storage.
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Old Mar 30, 2011, 09:27 PM
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great write up and contribution to the forum. I have decent idle, but i'll definately try and compare this to my current settings to see if I can improve it!!
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Old Mar 30, 2011, 10:02 PM
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Fantastic. I will be testing all of this tomorrow. Thanks.
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Old Mar 30, 2011, 11:23 PM
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Interesting theory.
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Old Mar 31, 2011, 09:09 AM
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Thanks, it took a while to write it all up. Like 2.5 hours. I tried as best i could in explaining it with confusing anyone. If their is anything i missed let me know. Also, let me know how this works out for you guys.

1 thing to add, after you get it idling correctly and you target rpm setup make sure you go back and smooth everything out. Using the graphs instead of the tables helps alot!
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Old Mar 31, 2011, 11:33 AM
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Whenever I adjust TPS I always do it manually and I suspected your findings would be like this.

Great job on the write up I know it will help many people in the future!
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Old Apr 5, 2011, 07:47 AM
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I see this is finding its way to the bottom.... How can we make this a sticky??
This is must have info for AEM users.
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Old Apr 5, 2011, 09:22 AM
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Yes this is great info. Really helped a lot.

My idle is still not steady with this info I am getting close. So I think 02 feedback also has a huge part to play in your idle. The biggest thing I still get is the car will be idling pretty well and then all of a sudden it will just shut off. As with any AEM you have to find the right combo for your car.
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Old Apr 6, 2011, 12:34 PM
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02 feedback doesnt matter much as long as you fuel table is correct boz. Verify that the ignition timing ramps up fast when the engine drops below target idle. If it does not then you do not have the ign vs target table setup correctly.
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Old Apr 8, 2011, 07:59 AM
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Ok, so after doing everything in the book to get my car to idle well, I decided to go back to the start and work from there. Well when I first put the triggerdisc ont he car, I had by borther help me with the base timing. It seems that there was a rock chip on my crank pully that he though was the timing mark. So my car was advanced about 15*. So I took some whiteout and hit the timing mark which was black, so now we could really see it. Got the cars base timing all dialed in and now the car idles super smooth all the way down to 875rpm, any lower and the correction just maxes out. So Over the weekend, I will adjust the BISS to get the idle down to 700rpm.

So if you are having wierd issues, go back and recheck everything. Start with all the sensors, and recheck that base ignition timing.
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Old Apr 8, 2011, 10:27 AM
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just to help... the IGN vs Target or whatever its called... the table in the drop menu for advance idle.
Anyways, i had an issue w/ idle hunting on a large intake manifold, 75mm tbody, cams, oversized valves/ported head etc...
Adjusting everything else did little to correct the problem... guess what finally fixed it?
That table... i previously had this table in a linear graph which i simply had it calculate from -10deg to +10deg when its correcting too high or too low rpm from the target. Well watching it live on the aem I could see that it was swinging from left to right all the way from one end of the graph to the other. Basically it was telling me it needed at least 8deg of timing -/+ to correct a 200-300rpm drop/climb. The fact that it needed to go across the entire table to do so was making the idle hunt up/down. Meaning by the time it hit the timing it needed to correct itself, it needed it to go the other way and was correcting too late.
So instead of a linear line from those two point... i brought the -8/+8 deg timing closer to the zero axis point so it immediately hit it. I knew it was working because the closer i brought it to zero the quicker the back/forth it was moving and the cell movement was getting shorter. Then eventually the closer to zero it was a stable idle at 1100rpm. Then i just leveled it out to -/+10deg correction and flattened it out on both sides to the 200-300rpm limits on the table. So it looks like a backwards "S" ? lol...

Last edited by TakaseEVOIXSE; Apr 8, 2011 at 10:30 AM.
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Old Apr 8, 2011, 11:55 AM
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^^^ Ding, ding, ding!!! We have a winner! Thats exactly how i fixed mine. This is what i meant about "getting agressive" with the ign vs target table.

Boz, glad you got it worked out man. I knew there was something else up when you said these settings didnt work. Your on the right track now though.....
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Old Apr 8, 2011, 12:28 PM
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ya the car is just amazing now. The idle is rock solid, all of these settings really helped. The other big one that helps a lot is the idle feed back rate. I also found that at about 14.5afr the car was very stable, but if I set the afr to about ~14.8 it would be a little more unstable.
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Old Apr 8, 2011, 01:20 PM
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Yes, the base maps idle feedback rate is too fast. I halfed mine i think. This way the ign vs target table has most control of the idle rpm. It will actually idle best around 13.5afr but the spark plugs wont last long at that afr. 14.5 would be fine though.

Last edited by browningderek; Jun 23, 2011 at 04:06 PM.
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