SAFC II wired with Zeitronix, Neither will turn on...

[teedoff00]

I hope this hasn't been gone over before, I have searched and haven't found anything. I have had my SAFC II wired in for almost two years, just piggy backed off the ECU, with inputs for B+, E1, IGT, and VTA. So when I wired in my Zeitronix I went ahead and piggy backed on the SAFC II wires, since I figured they shared many of the same inputs and then I wouldn't have to hack into the stock harness anymore. So the Zeitronix and SAFC II are on the same B+, IGT, and VTA. The only thing I didn't follow verbatim from isnms posts on how to wire the two was the ground. I used the E1 for both the SAFC II and the Zeitronix versus the E1 for the SAFC II and the E01 for the Zeitronix. I figured a ground was a ground, unless it is too much. I went ahead and cut the OX lead on the ecu and connected the ecu side to the Purple narrowband output on the Zeitronix. I also tapped into the ECU's vf wire and ran it to the user 1 on the Zeitronix.

SO... When they are both connected neither seems to be on. (car running) The Zeitronix doesn't show any data on my computer and the SAFC II is off. When I disconnect the Zeitronix harness, the SAFC II turns on.

So which input is causing the problem? Should I not be trying to run both of the same E1 or B+? I can't see how IGT and VTA inputs would have a problem since I would have to tap into them anyway. However I don't know if it was "bad form" to simply tap into the SAFC II existing leads versus making new taps onto the ECU's wires.

What could be my issue? What can I try? Any help or advice would be greatly appreciated!

Thanks!

Trevor

 

[teedoff00]

Ok, So I figured out my problem. It was actually quite simple. I figured I would go ahead and change the Zeitronix ground from the E1 that I had it tapped into to the E01 like in Isnms wiring diagram. It works great now! So for future reference. If using a SAFC II in parallel with a Zeitronix Wideband, you can simply tap into the leads from the SAFC II (B+, VTA, IGT) but run the ground on the Zeitronix to the E01.

So while I am on the subject. I put the Zeitronix in place of my stock O2 (using my wideband bung on the Downpipe for my AEM UEGO) I removed the Stock O2 and I am outputting the narrowband signal to the ECU from the Zeitronix. I have heard it is good to put a resistor to satisfy the HT circuit for the heater element on the O2. What ohm/watt resistor will do the trick? I am assuming a thick wire will work as I believe JetJock has suggested before. My car isn't throwing any codes and is actually behaving quite nicely, better than it has in a long time but I would prefer to not create any issue later on down the road.

Thanks for any help!
Trevor

 

[isnms]

Glad you figured it out. I don't have an answer for the resistor value.

Just to add to what ground to use:
http://www.cygnusx1.net/Supra/Library/TSRM/MK3/manual.aspx?S=FI&P=50
E01 = Power Ground
E1 = Computer Ground

 

[teedoff00]

Yeah those are the ones that I used! Thanks for making it clearer. Does anyone have any comment on the resistor? I am not even sure I understand why the ecu would have a problem with the O2 being disconnected if it is still receiving input from the OX sensor?

Thanks for the info! And thanks for you awesome wiring guides isnms!