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Old 03-16-2009, 08:57 PM   #1
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Default Can I get an AEM guru to check my calibration file?

As the title says. I installed an old calibration file when I got my car back. Now I need some assistance. Problems I'm facing:

1) I can't get the car to idle well when I turn my A/C on.
2) And of course, the old cranking issue is back.

I'm attaching my current calibration file. Could anyone knowledgeable take a look and suggest what should I change?

Thanks,

Rafa

Last edited by Rafa; 03-18-2009 at 06:58 PM.
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Old 03-17-2009, 12:12 AM   #2
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I'm no expert but I have gotten my idle to be pretty solid.

Some things I would try:
Idle --> Options Idle: Set your A/C on Delay to 1 or 2 seconds.

Increase your timing values in the 17.97 load row up to 30kpa , from 750 pm to 1500, to be around 12.5/13. Your timing map looks odd, like it was rescaled or something.

If you have a wideband, my AFR for a good stable idle is 12.5 or so. Really rich but it's rock solid.

There are some trim tables (most easily viewed as a graph) you can use to try and catch a drooping idle with load, one that does Ignition correction and one for fuel correction (these are for fine tuning though, not usually for "fixing"):

Ignition -->Advanced Ignition -->Ignition Trims --> Ignition vs. Idle Rpm:
This table allows you to control ignition advance relative to RPM and idle error
As you overshoot idle target (to the left) you can take away advance (retard) and bring idle back down or as you undershoot idle you can add ignition advance. The default setting is a nice smooth transition but you can ramp it up more steeply to catch a droop in idle.

The fuel trim works the same way (Fuel --> Advanced Fuel --> Fuel Trims --> Fuel offset vs. RPM).
You can add or take away fuel based on idle error and RPM.

Viewing/editing in the Graph is easiest as you can easily grasp what's happening with your changes and the idle error/RPM is shown real time.

This can be hours of entertainment :-)
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Old 03-17-2009, 12:41 AM   #3
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Quote:
Originally Posted by wroark View Post
I'm no expert but I have gotten my idle to be pretty solid.

Some things I would try:
Idle --> Options Idle: Set your A/C on Delay to 1 or 2 seconds.

Increase your timing values in the 17.97 load row up to 30kpa , from 750 pm to 1500, to be around 12.5/13. Your timing map looks odd, like it was rescaled or something.

If you have a wideband, my AFR for a good stable idle is 12.5 or so. Really rich but it's rock solid.

There are some trim tables (most easily viewed as a graph) you can use to try and catch a drooping idle with load, one that does Ignition correction and one for fuel correction (these are for fine tuning though, not usually for "fixing"):

Ignition -->Advanced Ignition -->Ignition Trims --> Ignition vs. Idle Rpm:
This table allows you to control ignition advance relative to RPM and idle error
As you overshoot idle target (to the left) you can take away advance (retard) and bring idle back down or as you undershoot idle you can add ignition advance. The default setting is a nice smooth transition but you can ramp it up more steeply to catch a droop in idle.

The fuel trim works the same way (Fuel --> Advanced Fuel --> Fuel Trims --> Fuel offset vs. RPM).
You can add or take away fuel based on idle error and RPM.

Viewing/editing in the Graph is easiest as you can easily grasp what's happening with your changes and the idle error/RPM is shown real time.

This can be hours of entertainment :-)
wroark; I thank you for your suggestions

You sure know much more about the AEM than I.

Some comments in the same order:

1) I'll try the A/C 1 to 2 second delay advice as soon as I can connect my laptop to it.

2) Your comments on the odd timing values shows you sir know your ****! I got my car dyno tuned with another calibration file but that one (along with most of the others I made) are in my other laptop which won't turn on and it's on its way to the repair shop to see if I can recover my data. If I recover it, I'll be able to upload that file again and you'll see the difference. Since my car's engine was rebuilt less than 4 days ago I have the time to work with the AEM without risking my car (I can't take over 3,200 rpm for the next 1,000 kms and I get the feeling based on my work schedule that it's going to take more than 4 weeks to do it).

and finally (for now ), 3) I do have a wideband. My car idles at 14.7 to 15 if the A/C is off and at 11.5 to 12.1 the moment I turn the A/C on. I get the sense that I'm doing something wrong and the car goes way richer as soon as I turn the A/C on.

I'll follow your advice on the rest of your suggestions but I have no doubt that it will lead to me making additional stupid questions

Many thanks man; lots of work ahead for me.
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Old 03-17-2009, 09:19 PM   #4
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Another dumb question: I've been re-reading the AEM manual and found this under Engine Calibration:

"It is essential that extreme caution be exercised in the initial set up of the fuel and ignition tables for the first use. We recommend very conservative settings for fuel and ignition. This means that a rich mixture is used for initial tuning and the ignition timing is at least 5 retarded from the factory ignition timing. In the case of turbocharged, supercharged of Nitrous Oxide systems, you should start with 10 retarded from the stock timing."

My dumb question of the day is the following: if Miata's factory spec timing is 10 degrees BDTC; does this mean you should set the timing at 0 degrees when making the original set up?
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Old 03-18-2009, 10:40 AM   #5
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Nope, 10 degrees is the base timing for a miata. There's never any reason (when you have complete control of the ignition timing ) to go below 10.
The ignition map in the AEM ignition table is total timing so base timing is always included in what you see. So, at idle speeds/loads in the ignition table you'll typically be seeing 12-13 degrees timing, that's base plus 2-3 degrees additional advance.
It's worth mentioning that those 10 degrees of base timing are ASSUMED as far as the EMS is concerned, you tell the EMS and it works from that assumption. Base timing is set mechanically by adjusting the CAS. IF you change your base timing (or it wasn't set properly when your engine was put back together) you'll never get what you expect when tuning UNLESS you inform the EMS that your base timing is something other than stock. Gotta go old school to theck it, break out the timing light.
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Old 03-18-2009, 01:34 PM   #6
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Quote:
Originally Posted by wroark View Post
Nope, 10 degrees is the base timing for a miata. There's never any reason (when you have complete control of the ignition timing ) to go below 10.
The ignition map in the AEM ignition table is total timing so base timing is always included in what you see. So, at idle speeds/loads in the ignition table you'll typically be seeing 12-13 degrees timing, that's base plus 2-3 degrees additional advance.
It's worth mentioning that those 10 degrees of base timing are ASSUMED as far as the EMS is concerned, you tell the EMS and it works from that assumption. Base timing is set mechanically by adjusting the CAS. IF you change your base timing (or it wasn't set properly when your engine was put back together) you'll never get what you expect when tuning UNLESS you inform the EMS that your base timing is something other than stock. Gotta go old school to theck it, break out the timing light.
Thanks.

I used the timing light and I set up my base timing at 10 degrees. I was just asking because in my previous calibrations, my base timing was set at 5 degrees in the AEM. This time around, both my base timing and the one in the AEM are set at 10 degrees.

I was just trying to confirm I hadn't done it wrong.
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Old 04-03-2009, 08:30 PM   #7
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Since I couldn't find a way to send my current calibration to Tim via pm I decided to attach it here.

I advanced the timing in the vacuum part of my map a little bit because I felt that my timing there was too retarted and I was seeing higher EGTs than what I'm accostumed too.

I also have an unresolved issue with a big discrepancy between what my WB O2 sensor reads and what my calibration file says. I'd like to know how to fix that.

Thanks,
Attached Files
File Type: zip Rafa 4-4-09.V1.19.zip (1.9 KB, 58 views)
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Old 04-03-2009, 09:27 PM   #8
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I'll try to look at this tomorrow if I get a free minute(s).

I use O2 feedback at idle to keep my AFRs around 15.5:1 at idle. I couldn't get my idle AFRs nice without it. If I cranked up the vent fan, turned on all 4 high beams, cranked up the wipers, volts go to about 11:1 and even with the voltage/inj pulse with table pretty set there's still not enough resolution (even with 440cc injectors) to get it smooth enough with just the tables (i think). I let the ECU automatically trim to a much finer resolution to what the AFR I want at idle.

I still use whatever the 90-93 1.6 AEM defaults were for the A/C enrichment. They work pretty damn nice on my car.
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Old 04-04-2009, 12:14 AM   #9
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Originally Posted by TurboTim View Post
I'll try to look at this tomorrow if I get a free minute(s).

I use O2 feedback at idle to keep my AFRs around 15.5:1 at idle. I couldn't get my idle AFRs nice without it. If I cranked up the vent fan, turned on all 4 high beams, cranked up the wipers, volts go to about 11:1 and even with the voltage/inj pulse with table pretty set there's still not enough resolution (even with 440cc injectors) to get it smooth enough with just the tables (i think). I let the ECU automatically trim to a much finer resolution to what the AFR I want at idle.

I still use whatever the 90-93 1.6 AEM defaults were for the A/C enrichment. They work pretty damn nice on my car.

Thanks Tim.

BTW, I checked the wizard. My tuner never calibrated the first O2 sensor I had.
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