afc issues~ Please Help! on Ka24de motor ..... afm signal problems

[SpeedyZman]

I was needing to do the install to correct my car running WAY too rich....I asume it is running rich as I have removed allmost all the vacuum lines and egr stuff using block-off plates and blockoff plugs to clean up the engine bay as well as removing anything unneeded such as doing the throttle body water hose bypass removing the hoses and also the metal hoses and vacuum lines that run thru the intake plenum and behind the engine including the swirl control valve---- (which I still am wondering what that does!)

It's to be an autocross car and I'ts been COMPLETELY gutted,.....no ac/heat/even removed all the insulation on the firewall.....everythings been removed and cleaned before installing the motor as this was a flood car previously,,,,,,

I've got the other features of the AFC working great including the Rev meter & the Throttle %.....

I'd like to get that afc install completed asap to cure the car from running way too rich,......its blowing black smoke ..... (spark plugs black with soot as well thus the diagnosis) as the engine was running great when it had all the emissions stuff intact,,,,,

the car actually seems to idle better when you unplug the maf sensor as well- but thats probably due to the ecu receiving the incorrect signal of 5+volts instead of around 1.3 or so at idle....

I've got the afc set on 5in 5out as the us manual update stated the ka24de motor was a hw-5 sensor model.

I also swapped a known good afm from another s13 i own to make sure that wasn't the problem and it does the same thing.

the AFC keeps showing I'm at 100% airflow even when the car isn't turned on (key in accesory position) due to the 5+volt signal from the white AFM sensor wire,....

Please HELP me figure this thing out as it's driving me crazy!!!!

thanks in advance for the help!Damon 417-860-8710

[AX75F92]

Sounds like the issue is beyond the SAFC. Could be a hardware issue (you disconnected a lot of stuff, quite possibly something important), could be an electrical issue (wiring of the AFC may be incorrect, or maybe you overlooked some things when reinstalling the motor). If your factory AFM is reading 5+ volts at anytime (let alone idle...) something is wrong. The AFM should never read anything beyond the 0-5V range (most Japanese vehicles operate within a common 0-5V range). The SAFC was programmed with this in mind, therefore the SAFC itself does not recognize anything outside of 0-5V. This is why the SAFC will not work on many American cars (signal ranges outside of 0-5V). Check your wiring.

[SpeedyZman]

the maf ground had gone bad somehow....

the Black wire on the maf connection wasn't showing that it was properly grounded when I did a continuity test between it and the negative terminal.....

so I then hardwired a new ground wire to the black wire and walla! it was showing the correct voltage and now the afc seems to read correctly.....

that was it!

I am now trying to find a correct wiring diagram for the z32 maf so I can wire it up to the car now.....

if anyone has a known good diagram please post it!

Many thanks to those that responded!Damon

[AX75F92]

Ill post it tomorrow, if you havent found it by now. Is the stock KA MAF the same as a stock S13 SR20 AFM? I only have the diagram to convert the SR20 to Z32...

[WeldingHank]

i belive the SOHC KA MAF is the same as the SR20. and the DOHC KA MAF is different.