Question on testing sensors (maf, tps,...)

[wei240]

so redtop decided to blow black smoke and idle on the verge of stalling out (which it does sometimes), and shaking engine...

car was running fine couple months prior

so i checked the ecu, it's code 12 = maf

so how do i actually test the voltage of maf, or tps, or any other type sensors,am i suppose to test the voltage of the plug itself (with the wires going to the ecu) or the physical sensor itself? i'm assuming the plug (with the wires) since it'll have some type of current?

sorry for such a noobish question, never had any issues with my ka for many many years until i got the sr couple months back...

oh, and i pressure tested for boost leak, which i did find one by the throttle and fixed that, so it's not boost leak...

thanks

[S13FASTBACKSR]

the black wire with a white stripe is your power wire that should be 12v. the white should be 5v and the black is a ground...also unplug your mafs and try reving the engine past 2000-2500rpm..if it revs past that then your maf is bad...or ecu (but in your case it would be maf since the ecu tells you that is the problem and your symptoms definately sound like a bad maf) ...when your maf is unplugged the ecu goes into "limp" mode and shouldnt rev past the 2000rpm or 2500rpm range..if it does then your maf is bad

[vancouverbc]

its in the factory service manual.