I've had issues since my AEM Series 2 was installed. When searching it's clear this concern is fairly common, even with a stock computer, but for most cars it seems the idle dips and slight shuttering really isn't a problem - it's just the nature of the car. Before the EMS upgrade I had the idle dip when the A/C or fan came on, but that was about it - a momentary dip with a recovery. I didn't worry about it.

Since my EMS change it's been a problem. Stalling, even when stopped is not safe. Stalling at drive thrus, stalling at stops, stalling when putting the top up/down... Excessive shuttering is also not good. I believe the underlying problem could be an underpowered alternator, but I have not found that to be proven out anywhere.

Anyway, I've played with some idle and O2 feedback settings and the stalling has quit. I'm getting an etune now through Evans and Jeff had my idle at 900. With the AEM my car doesn't seem to like a 900 idle, nor does it seem to like the 14.7 AFR at idle. Tonight I did an idle tune following a DIY I found from another Honda forum. With idle AFR's in the low 14's and a 950 idle the car did much better - fan and A/C cycles included. I upped the A/C load to 5.1% and the transition was much smoother. Of course I could feel/hear the load cycles but RPMs only dripped 75 or so, over recovered 75 or so on the high side and went right back to a nice little window. I even tried turning the A/C on as the fan cycled on to challenge it and that was no problem.

So, are slightly higher RPMs and slightly rich the answer? What are your targets for RPMs and AFR at idle? Am I getting somewhere with this, or am I missing something?

My S is supercharged with a Comptech Novi 1000. Map sensor has been replaced, car only has 27,000 and everything inside and out is clean as can be. I have not checked the valves, but with the mileage there should not be issue and there was no concerns until the AEM was installed.

Feedback, thoughts and ideas appreciated.

 

Watch this video

http://www.youtube.com/watch?v=4CfP-W5bu5c

I used to have my idle at 1000rpm at 5 ignition timing. Stable and no dips. A/F 14-15

To minimize fluctuations, you need adjust pulse width on the the fuel map at -10psig to -8.5psig to not have a large delta change from cell to cell.

Then you need to adjust the idle% vs Target to get and idle learned value between -5% to 0%.



Currently I'm at 1200rpm idle and 20ignition timing. It gives me less cabin vibration with the aftermarket motor mounts.

I'd say find a setting you like and if the idle is stable, just leave it.

Notice how I set 500rpm and -6.1 PSIG on the fuel map to 3.0. That is to give it more gas if the motor stalls. It works for me when the fan kicks in and my RPM drops.

 

I had similar idle problems when my car was first tuned so I took it back to my tuner to have him spend a bit more time in that area. My tuner has my idle set at 1,000 RPM, +100 RPM when fans are on, but my AFR reading from my AEM gauge at idle is always in the 11-12's. I know its rich, but the car no longer has stalling or rough idle issues; it idles great. I figured I would leave well enough alone.

It seems like a slightly higher and richer idle will produce a more stable idle.

 

Thanks guys. I watched the video this morning, he did a nice job explaining some things I haven't touched and didn't understand. I started to watch it in the past but got out of it when I saw the Supra.

I prepped a cal this morning to go through another idle tune, taking idle up to 1000 rpms - don't think I need 1200. I like the fuel bump at 500 RPM's, makes sense. Going to try to keep the AFR in the high 13's. I'll load it up at lunch today and see how it plays out.

When working through it last night I turned the O2 feedback off and turned it back on when done. It seemed a little smoother when off. Can I leave it off? Doesn't it only work at idle speeds?

 

http://forums.evolutionm.net/aem-ems...e-aem-ecu.html

Follow this and your idle will be pretty much perfect. Still get a slight dip when the fans kick on but will not die guaranteed.

 

air fuel at idle 100% depends on your injectors. If you have really good injectors you can idle it lean, if you have junk it'll have to be rich.

If the car dies the idle just isnt set up correctly.

the aem base maps come with the idle error vs ignition timing set to add and pull timing based on the error.. zero those tables out.

Also turn off o2 feedback until you get it dialed in. If the car is tuned right 02 feedback wont make any difference anyway.