3.2 Tuning
 

Howdy everyone.

Once upon a time I had compiled a couple different threads on how to "tune" a stock 3.2 motor. I cannot find the links or the threads.

Specifically, I am trying to figure out how to adjust the MAF (the barn door thing) the ECU (or motronic or what ever we are calling it today) and the Idle bypass.

I recently got a new exhaust on the car so I can actually use a WBO2 sensor that will give accurate readings.

Sorry for my inability to effectively use the search feature and thank you all for your help!

Andrew

I'm sorry I can't help you find the threads you're looking for, but I can provide a little clarification.

The "barn door thing" is an Air Flow Meter (AFM), which is very different from a Mass Air Flow (MAF). You're correct in calling the ECU an ECU. Most here seem to like calling it a DME, which is technically incorrect. It's an ECU. By "idle bypass", are you referring to the idle control valve?

There isn't any tuning of a Motronic system other than to replace the stock chip with an aftermarket one that has revised fuel and/or ignition maps. The system uses inputs from various sensors, including the O2 sensor, to adjust itself to varying conditions from moment to moment. The idle controller can be adjusted with a screwdriver, but that isn't really "tuning" in the traditional sense. So if you're talking about tuning for performance improvements, that's going to be limited to a chip and hardware such as exhaust, cams, AFM to MAF conversion, etc.

Thanks for the reply porschenut!

In calling it a DME kinda got me on the right track. I found:
http://forums.pelicanparts.com/porsche-911-technical-forum/484188-afr-problems.html

Which actually has the procedure:

CO = 0.8% or AFR=14.2

Setting base idle and CO mixture
1) Oil temp at 90C
2) All electrical consumers off (AC, heat, lights, ...)
3) O2 sensor unplugged
4) Adjust the CO screw on the AirFlowMeter for CO=0.8 or AFR=14.2 (clockwise=richer)
5) Now connect O2 sensor
6) Bypass idle speed stabilization by bridging B&C terminals on test port (left side near rear fuses)
7) Adjust idle speed with bypass screw on ThrottleBody, 84-85 cars are 800RPM 86-89 are 880RPM, set base idle 20to40RPM above target, if target is 880RPM set base at 900 or so.
8) remove jumper

If you follow this procedure and you find that turning the AirScrew on the AFM (not the ThrottleBody) does not cause the mixture to alter then something is wrong with the AFM.

and a little later in the post adjusting the DME is discussed:
fuel quality switch should be in full counterclockwise position.
https://www.lindseyracing.com/LR/Parts/DMEFQSSWITCH.html for a how to

[QUOTE=porschenut;10420832]
You're correct in calling the ECU an ECU. Most here seem to like calling it a DME, which is technically incorrect. It's an ECU.

not that it makes a hill of beans and most people know what is being referred to whether you call it an ECU or a DME, but technically its called a DME control unit not an ECU SmileWavy

Andrew, if you want the best tuning available for a 3.2 contact Sal Carcellar on this forum. his products and knowledge of the 3.2 DME systems is incredible and his pricing is very fair.

Richard