NA 1.6 Map sensor wiring
The wire colors in the install manual are incorrect for both the MAP and IAT sensor when using the AFM connector and the PNP Harness.
In order to wire the map sensor in at the AFM connector you must use the following:
MAP Miata --------MAF Harness
A (gnd) ------------Black-Lt Green
B (sensor) --------- Red (2O)
C (+5V) ------------ Lt Green-Red
The usual way of connecting the IAT is to use the Lt Green wire and the Black-Lt Green ground wire. This can not be done using PNP harness because the Blue wire that the ecu uses for IAT input terminates on the board of the PNP harness and does not connect to anything. It is in a sense a dead wire on the PNP harness.
In order to wire in a IAT sensor with the current PNP harness you must desolder the blue wire for the ecu IAT and run your own wires. The OEM wiring is not PNP at the moment.
Hope that all makes sense. I'd be happy to clarify if its not.
Brian
In order to wire the map sensor in at the AFM connector you must use the following:
MAP Miata --------MAF Harness
A (gnd) ------------Black-Lt Green
B (sensor) --------- Red (2O)
C (+5V) ------------ Lt Green-Red
The usual way of connecting the IAT is to use the Lt Green wire and the Black-Lt Green ground wire. This can not be done using PNP harness because the Blue wire that the ecu uses for IAT input terminates on the board of the PNP harness and does not connect to anything. It is in a sense a dead wire on the PNP harness.
In order to wire in a IAT sensor with the current PNP harness you must desolder the blue wire for the ecu IAT and run your own wires. The OEM wiring is not PNP at the moment.
Hope that all makes sense. I'd be happy to clarify if its not.
Brian
Its would be nice if the Blue wire for iat sensor on the PNP went to the Red/Black wire on the car harness, but they are using it for fuel pump under one of the aux ports (5 or 6 i think). I think I'm going to change it so that it is and just jump the Lt Green to Black/Lt Green. This will turn on the fuel pump whenever the ign is on. Might not be the safest config ever, but I'll try not to get into an accident (which is the only time you dont want the fuel pump to continue running.)
I'm not sure if it is necessary for the pnp harness but I had to cut a ground at the back of the intake manifold to get rid of some really bad sensor noise.
This is the wire.
This is the wire.
Was it something you noticed immediately. My stock temp sensor is reading correctly when I turn the car to on. I haven't started the car and ran it yet though. Still need to fab some things so I have my IAT and WB O2 permanently installed.
Here is the thread where I worked on it. There are before and after log pix.
Its not something you'll notice until the car is running and even then at low inj duty cycle its not as apparent. You'll definitely notice at higher duty cycle.
Its not something you'll notice until the car is running and even then at low inj duty cycle its not as apparent. You'll definitely notice at higher duty cycle.
You were right, lots of noise. Going to cut the wire tomorrow. I have only idled the car so hopefully I haven't killed the sensor yet. I'd say that this modifications is officially a requirement on NA1.6 cars running the stock water temp sensor.
Is it only on the water sensor like mine was?
You'll be able to tell if you killed it. Keep an eye out after you're up and running for a sudden temperature drop and then it will hold at that temp for a while and then pop back up. That behavior can also pop the ecu out of closed loop fuel & idle.
I kept looking through the adaptronic forum after I found that wire and eventually found a post that mentioned from about 4 years ago. I mentioned it to Travis a while back but he didn't add it to the docs.
You'll be able to tell if you killed it. Keep an eye out after you're up and running for a sudden temperature drop and then it will hold at that temp for a while and then pop back up. That behavior can also pop the ecu out of closed loop fuel & idle.
I kept looking through the adaptronic forum after I found that wire and eventually found a post that mentioned from about 4 years ago. I mentioned it to Travis a while back but he didn't add it to the docs.
Nothing has been updated on the docs. Every car is going to get its own manual and its in the new beta manuals, but those aren't out yet. Trust me I listened I take customer findings very seriously, and really appreciate contributions to the knowledge base.
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Zaphod
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Oct 26, 2018 11:00 PM





