s5 afm trouble code help
 

91 n/a.

so i have a code 8 for the afm circuit. i've already checked the afm, and it's fine and have not yet checked to see if the signals are making it through the harness to the ecu yet. i will be doing that shortly.

is there anything else that might cause an afm code even if the whole afm circuit is fine?

there is also an unshielded wire coming out of the harness along with the wires that go to the afm plug that looks like it broke off of something. i'm assuming this is a ground and currently have it grounded.

Get the wiring diagram from the link below and check out the function of the wire. Don't assume it is a ground wire. Chances are that it is not.
http://foxed.ca/foxed/index.php?page=rx7manual

thanks for the link. i already had the full fsm, but was missing the full wiring diagram. it didn't end up helping this time, but i got curious and cut open the harness a little further and found this.

https://www.rx7club.com/attachment.p...1&d=1268007817

i believe it's the shielding for this wire

https://www.rx7club.com/attachment.p...1&d=1268007817

now i'm unsure of what move to make next. i'm not sure if that small of a portion of unshielded wire would be causing my problems. maybe try wrapping the rest in aluminum foil?

that shielding wire isn't supposed to be attached to anything, don't worry about it.

The shield is grounded on the other end of the cable. See FSM wiring. And or just put a meter on the shield and check for ohms to gnd. That will show it's grounded on the other end. Much like a series four CAS shield.

The three shields for the afm.....02 sensor......knock sensor.........all are spliced together and grounded at the same point. See wiring diagram.

I doubt the lack of the shield being grounded would cause your problem/code......if indeed it is not grounded.

alright measured the voltage at the ecu on pins 2b and 2k. they are in fsm specs. but at pin 2L for the engine intake air thermosensor i got 4V instead of 1-2V when warmed up at idle. i'm assuming the iat is just a resistor sensor and that it's shorted. would that cause the afm code? or is it an unrelated problem?

just found out that it has it's own trouble code (11), just won't show up until i fix the afm trouble code (08) because it's a lower number :rant:

The only time I've ever seen an AFM throw a code is when the resistance would 'blow open'. It's not supposed to read in a linear fashion, so don't worry about that.

ugh. so i measured the resistance at the actual iat sensor and it's perfect.

so i have an afm code. but the afm tests perfect, and the wiring tests perfect..............

Have you checked the wiring resistance/for shorts/etc? Also, it could read fine at the positions, but the resistance could have shorts at various positions.