Casey96SS

Going to be installing a new AEM Wideband O2 sensor and gauge this weekend.

I plan to tap into the AC pressure sensor wire so I can log the O2 readings in datamaster. I bought a 3 way switch so I can switch between O2 logging and AC operation since I am retaining my AC.

Just wondering if anyone has any tips on where to physically tap into the AC wires? I figure I can either tap in near the PCM plug, near the AC compressor, or somewhere in between. I am trying to do a clean install so the extra wires are not noticeable. Also, any tips on the the best place to pick up power and ground for the meter? All the posts I have read do not seem to mention much on where to physically tap into the wiring.

Thanks for any input.

madhatter

In for this. I have wanted to do the same style install for a while now.

ws6t3rror

iTrader: (3)

The switch/wire you want to tap into is near the strut tower. I usually install them onto a single pole double throw switch. That way you can quickly log for tuning, and switch back to using the a/c. The strut stud usually makes a handy place to fab a bracket to hold the switch.

Needless to say you can't use the AC when logging.

hokeplaya05

iTrader: (3)

I don't have AC so I cut the wire almost back to the PCM plug and then spliced directly into it. I grounded mine to an existing bolt on the firewall and spliced the power into a 5v source (radio power wire IIRC) so the wideband stays on until I open my door after shutting the car off.

Casey96SS

So I finally got this all wired up. I used the extra auxiliary power wires under the front of the console for the power and ground for the gauge. The gauge turns on and off with the key. I had to extend the blue wire that is the 5V output to reach to the front of the car. I used 16-ga wire wrapped in shrink wrap for extra abrasion protection. I made a small hole in the lower shifter boot and ran the blue wire extension and O2 wire harness through there. The blue wire extension is zip tied along my fuel pump hot wire over the tranny and up near the pcm. Under the hood I soldered a piece of paper clip on to the end of the wire so I can just stick the clip into the pressure sensor plug when I want to log.

The gauge seems to work perfectly on it's own and readings are accurate as far as I know. I am getting high 14's at part throttle and low 12's at full throttle the way the tune is currently set up.

Strangely, one thing I found was that the gauge causes an incorrect communication error in winflash when trying the read the PCM. I found I have the disconnect the gauge to load a tune. Maybe this has something to do with using the auxiliary wires for the power?

I tried datalogging in datamaster yesterday and I cannot seem to get this thing to log correctly. My custom data reading jumps all over the place from 10 to 20 and does not match what the gauge is saying.

I followed this thread: http://www.camaroz28.com/forums/comp...-535603/page4/

My AEM is a newer model 30-4110 not the older 30-4100. Still, 10 AFR = 0V and 19.98 AFR = 4.99 V. I set the gain in the custom data to .0392 and offset to 10.

Anyone have any idea why the reading is jumping all over in datamaster? The voltage on the blue wire reads correctly with a volt meter. Getting 2.50V @ 15.0 AFR. Grounding the AC pressure ground made no difference. Should I try to ground the gauge somewhere besides the auxiliary ground? I am out of ideas.

Casey96SS

Tried playing around with this some more today. I hooked the power lead and ground for the gauge directly to the power posts under the hood. I also spliced the blue wire from the AEM gauge into the black and red wire in the pressure sensor while the plug was connected to the pressure sensor. I did not know if the black and gray wires in the harness not being connected would affect anything.

After all the changes in the wiring I am still not getting any change in datamaster. The custom data box for byte 30 just continuously counts backwards from 20 down to 10 repeatedly. It does this whether the car is running or if the ignition is just on. The custom data reads a steady 10 if I disconnect the blue wire, so I know data master is seeing something while it is connected. The blue wire still measures the correct voltage when check it with a volt meter.

I am completely out of ideas on this one. I ruled out all my connections and checked my math. This should work. I think it is probably something to do with datamaster although all my settings look correct and I cannot see anything else to change. Would having an OBDI PCM in a 96 OBDII car being causing any issues? Any other ideas?

Casey96SS

So apparently I cannot read instructions. For anyone using an AEM gauge in the future, make sure you use the white wire from the gauge to tie into your black and red AC pressure wire. Do not use the blue wire from the gauge. Reads fine in datamaster when using the white wire.

tom camaro

I may have missed something but why are you tapping the AC lead for power?

Casey96SS

The AC pressure wire is just used for logging the O2 readings in datamaster. There are numerous write ups on it.

I used the aux power and ground wires near the shifter to power the gauge.