NickD
NickD UltraDork
2/17/18 3:53 p.m.

In my ongoing supercharged 1.8L swap into my 1990 Miata, I am adding an Innovate A/FR gauge and an Auto Meter analog boost gauge. What circuits/wires should I wire into exactly to add these gauges in? Thanks. I'm kinda clueless when it comes to electrical stuff like this.

Robbie
Robbie PowerDork
2/17/18 5:32 p.m.

Well, don't over think it. Both of those gauges probably only need switched 12v, ground, and maybe a dimmer or dash light signal wire. The boost gauge will then have a vac line, and the afr gauge will have it's own wiring to the sensor.

A quick look in a manual for radio or HVAC panel or dashboard wiring diagram should tell you where to grab switched 12v and dimmer. You can tie into an existing ground easy too.

Keith Tanner
Keith Tanner MegaDork
2/17/18 6:01 p.m.

IIRC, white with a red stripe is switched power. They're everywhere.

Rodan
Rodan Reader
2/18/18 9:41 a.m.
Keith Tanner said:

IIRC, white with a red stripe is switched power. They're everywhere.

This.

The AFR gauge should come with it's own harness for the wideband sensor, so you're really only looking at power/ground if it's just a monitor.  Are you using aftermarket engine management?  If so, then you will want it talking to your ECU, which may be a little more involved.

Mechanical boost is pretty straight forward... only wiring should be for illumination.  You'll want to tap into the output behind the dimmer switch on the dash, left of the steering column.  I used the wiring diagram below when I did my VVT swap... you should be able to find what you're looking for on it.  You might want to get a magnafying glass... wink

1990 Miata wiring diagram

Keith Tanner
Keith Tanner MegaDork
2/18/18 2:03 p.m.
Rodan said:
Keith Tanner said:

IIRC, white with a red stripe is switched power. They're everywhere.

This.

The AFR gauge should come with it's own harness for the wideband sensor, so you're really only looking at power/ground if it's just a monitor.  Are you using aftermarket engine management?  If so, then you will want it talking to your ECU, which may be a little more involved.

Mechanical boost is pretty straight forward... only wiring should be for illumination.  You'll want to tap into the output behind the dimmer switch on the dash, left of the steering column.  I used the wiring diagram below when I did my VVT swap... you should be able to find what you're looking for on it.  You might want to get a magnafying glass... wink

1990 Miata wiring diagram

The gauge in a wideband usually contains the controller, so it’s self-contained. Hooking to a ecu is typically a single wire that contains a 0-5v signal. 

I think the boost gauge instructions on the FM site include the info you need for hooking into the lighting. 

NickD
NickD UltraDork
2/18/18 2:47 p.m.

I'm running MegaSquirt PNP9093

Keith Tanner
Keith Tanner MegaDork
2/18/18 3:15 p.m.

This makes no difference. 

Rodan
Rodan Reader
2/18/18 4:49 p.m.

The 0-5V signal wire from the  wideband controller goes to the O2 sensor input for the MS.  Not sure which wire it is on the PnP versions, but your documentation should have that info.  There should probably be power and ground for the controller as well.

NickD
NickD UltraDork
2/19/18 5:15 a.m.

In reply to Rodan :

So I just toss the stock O2 sensor?

Rodan
Rodan Reader
2/19/18 7:48 a.m.

Yes, the wideband replaces the stock O2 sensor.

NickD
NickD UltraDork
2/19/18 10:20 a.m.

Okay. Like I said, electronic stuff I am not so strong on. 

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