Aswilley

iTrader: (1)

Ok, so if any of you have read my build thread then you know I have a 97 SC300 and did An OBD1 Aristo ECU conversion. The issue I am having is the TAC gauge doesn't work.

I know that in the earlier models you could jump the R109 resistor and wa-la you have a TAC again. However, on the 96+ clusters, the signal must be different or something. Cause my TAC doesn't work and there is no resistor to jump. It seems like the signal is transformed either at the old ignotor or somewhere in the printed circuit of the cluster.

Ok so here is my theory on how to get a 96+ TAC gauge to work,with this mod... and PLEASE any opinions or thoughts would be greatly apappreciated.

When doing the TT ECU Mod you replace the Ignitor with a DS62 .. What if in theory you could piggy back the old (original Ignitor) to convert the tac signal back and get the gauge to work..

Here is how.. (I think)

When looking at your DS62 ignitor everything is hooked up (depending on stock dizzy or not).. what if you piggy backed the old and new ignotor together via jumping the old ignitor in the new ignotor using:

C1
B+
and GND ..

So both ignitors will be powered, grounded, and signal going from coil to both. Then you would move the tac signal wire back to the old ignotor so the cluster get the right signal but leave all the IGF and IGT (and coils of using COP) plugged into the new DS62..

In theory the old ignitor should be powered, grounded and have the C1 from the coil being proccessed and outputting the correct TAC signal.. Yet the new DS62 will be the one comunicating to the ECU..

Let me know if anyone would like to see a diagram and I will make one in Paint and post it to get a better idea.