IM TALKING ABOUT PIN 2A

ok i have gotten a new ecu and traced resistance from that wire to the AFM which was supposed to be an open line... when removing the AFM the line becomes open and clear of all resistance... well i just got a AFM from somebody on the board and it has up to 4 times as much resistance as my old one.. and the readings on the test for an AFM does not even work.. does this mean my new AFM is bad? should there be any resistance from the AFM on that wire.. i wouldnt think so.. i think i bought a dud by honest mistake... i do not want to actually plug in my ecu and find out the new AFM was bad and be out of another god damn ecu and have to pay another 50 bucks... thanks in advance

christopher

 

BUMP... is there a way the wiring harness can all of sudden go bad so that when i plug a new one in it automatically goes bad too?

 

any help guys?

 

The BrW wire supplies 5v ref voltage to several items. 1. to the AFM, 2. to the Atmospheric Pressure Sensor, 3. to the boost/pressure sensor, 4. to the Variable Resistor, 5. to the TPS.

If you disconnect all these items and the middle plug on the ECU, THEN the wire should show no resistance. But not until all those items are disconnected.

Here's a schematic showing the BrW wire and what it goes to with the exception of the ATP (atmospheric pressure sensor) which is to the far right and got cut off in this jpg. The RED marks were for another post, not yours.

https://www.rx7club.com/forum/attach...&postid=601909

 

A little bit better jpg:

 

so when i plug that AFM in i am supposed to get resistance? there is no resistance until i plug that in even with the other 4 plugged in though?

 

is there a way to check the AFM harnes.. not the afm itself but the harness that hooks it up for problems.. is there a way something in that harness could go bad?

 

I don't understand you.

See the jpg above? Find pin 2A. Pin 2A feeds those items I listed above.

If you put a meter on ohms, and one lead of the meter to socket 2A on the harness, and the other to ground....you will see resistance.

If you disconnect just one of the items from the harness you will still see resistance on the meter. As long as any one of the items is connected to the harness you'll see resistance.

If you get on socket 2A (of the harness) as described above, and remove all the items above from the harness, then there should be an open circuit. That's how you would see if there is a short in the harness.

If you suspect the harness might have a short in it, you would put one meter lead on socket 2A and the other lead on ground........and read the meter while someone massages the harness. The meter should read open unless the massuse (sp?) makes a bare wire touch ground thne the meter should read something.