Sorry if this post is in the wrong thread, or a repeat; but I felt that none of the threads I read, adressed this specific question/ option when wiring an AEM afr with a MsPnP2. So here it goes...

Ive got a 30-4110 AEM afr UEGO controller/guage, and Im looking to wire it into my ecu. Fair enough, there are two threads which cover this topic and a few on miata.net, however none were explicitly clear on the best way to get this done, and i found that some had conflicting information.

As far as wiring goes i have two diagrams to work off, the AEM one and the DIY diagram (both picutred Bellow).
Other threads have said to wire the white wire form the AEM to pin 21 on the MS which is the O2 input pin. Makes sense.
However next they say to wire the Ground from the AEM to the ground of ECU...okay if you say so...They say to splice the AEM ground into the ground on the ECU harness.

My question is why not, instead of splicing into the hanress , just plug the ground of the AEM into pin 22 on the options port of the MS labeld "signal gorund".

Wouldnt that be the same thing, and avoid any unessiarry tampering with the stock harness?

Thanks for your help, Kevin

 

AEM instalation Wiring Diagram

 

MsPnP2 Wiring Breakout Diagram

 

Wire to 21 and 22 in your options connector. Power from a fuse tap or other clean fused 12v source. Done and done.

Other threads were probably lazy to run wires, or their ECU did not have an options connector. MS2!=MS2PNP

 

Thanks, Man just wanted someone else to confirm because I clearly haven't done it before; and I wasn't brave enough to cross into uncharted waters alone XD.

 

I wouldn't ground to the signal ground -- instructions even say chassis ground. so use pin 5 and 21.