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Old 05-23-2012, 09:47 PM   #1
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Default AFM/ECU signal wire

Anyone know which wire on the MAF is the signal to the ECU? I've been scouring through diagrams and forums and I feel like I'm looking for the Red-Grn wire. I'd like to be a little more sure of that.
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Old 05-23-2012, 10:13 PM   #2
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I've found that there are only two wires that run between the AFM and the ECU. Red and red-green and I'm now leaning towards red. If anyone knows for sure plz fill me in.
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Old 05-23-2012, 10:49 PM   #3
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I assume its for your 1992???

here you go:
http://www.dbmiata.com/information/ecupin.html
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Old 05-23-2012, 11:38 PM   #4
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For a '90-'93 car, the airflow signal is a solid red wire that runs from terminal F of the airflow sensor to terminal 2O of the ECU. This is a direct run that does not pass through any intermediate common connectors. For most of its length, the red wire is enclosed in a black plastic sleeve which can make it difficult to identify.

The red/green wire is the intake air temperature signal.
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Old 05-25-2012, 09:53 PM   #5
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Thanks very much guys. I was feeling good about red. Now I'm much less nervous.
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Old 05-27-2012, 08:15 PM   #6
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Hey guys, I pulled the harness open on my AFM and as confident as we all are that the red wire is necessary, there is no red wire in it. Every wire colour is present with the exception of a solid red. There is, however, a larger gauge Gry-red in there. I'm wondering if I'm being over cautious by not assuming it's the same wire. Just so everyone knows, I live in Ontario and have a canadian miata. I don't know if that makes a difference in this case but I do know that the DRL/turn indicator wiring differs from the US, UK, and Japanese models. Any knowledgable Kanucks out there with helpfull info? I can't find any canada specific diagrams.
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Old 05-27-2012, 08:33 PM   #7
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Ah, you motley Canadian bastards with your Soviet-style wiring...

Ok, so the AFM has seven wires going to its connector:



The airflow signal is on pin F, which is the second one in from the end.

If you can't tell by sight which end is which, figuring it out is easy. Test with an ohmmeter between ground and the pin in question on the vehicle's harness where it mates with the AFM. The second pin in from the wrong side is ground, so you'll read appx zero ohms.
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Old 08-30-2014, 09:30 PM   #8
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Quote:
Originally Posted by Joe Perez View Post
From left to right, the pins are:

IAT, AFM, signal gnd, +5V, signal gnd, power ground, and fuel pump.

It is the last 2 that are shorted to run the fuel pump.
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