Ok so heres the situation, I have an 87 gxl, and replaced the harness in the bay. The replacement harness that was used was supposed to be from an 87 as well. Everything seems in order and I go to start the car, it cranks and starts and hits about 1000 rpm or so and dies right away. Sounds kind of like the maf sensors unplugged to me so i go check the plug. Under closer inspection the new maf plug only has 6 pins used, the top of this clip btw says A04, the old plug from my original harness has 7 pins used, and the plug reads A03.

From left to right on the a04 slots 1, and 2 are used, 3 is empty and 4 to 7 are used.
The a03 every slot is occupied.

So my question is what is that 3rd pin used for? Is there a way to use my a03 plug on my a04 harness?

 

Page 4A-53 FSM. Link to FSM in the FAQ.

 

The third and fifth pins are both grounds. They're in parallel with each other, so in theory you only need one of them. I presume Mazda had a reason though...

See pages 4A-54 and 50-31 in the FSM for wiring diagrams of the AFM.

 

fc3s.org doesn't have the manual anymore, and iluvmyrx7 is down

 

So if its just a parallel ground it should be working anyways right? Do you guys have any idea as to why it would start and die immediatly?

 

The connector on the AFM (as facing the AFM):
1 2 3 4 5 6 7
FC E1 E2 VREF E2 VS THA

(static tests)
E2 to VS 50-500 Ohms
E2 to VREF 200-500 Ohms
E2 to THA -4 degrees 10,000 to 20,000 ohms
32 degrees 4,000 to 7,000 ohms
68 degrees 2,000 to 3,000 ohms
104 degrees 900-1300 ohms
140 degrees 400-700 ohms
E1 to FC Open

(Dynamic tests)
Fully closed Fully open
E1 - FC Open Short (0 ohms)
E2 - VS 50-500 ohms 50-500 ohms (figure that one)