To begin im not putting the engine into a supra.
but i would love some help.

that being said, as i browse the web, it crops up now and then, people having issues with the ECU cutting out at 2500+rpm when the 1jz tachometer is not conected for a feedback signal. Is there a way to bypass this without
A. getting the 1jz tach
B. getting an Aftermarket ECU

is there a modification that can be made?

i have an after market tach is there some way to utilize that?


-thanks

I don't know too much about the 1JZ, but the ECU adjusts the ignition timing advance based on load and RPM... installing a signal generator (a simple CMOS 555 circuit would do the trick) won't have the engine running to it's full potential and could possibly cause damage at higher RPM (imagine running the engine with 40º of timing pulled).

Your aftermarket may have a freq. output. What brand and model is it? You'll probably also need to know the stock tach's scaling.

everything engine control wise is based from the cam sensors.

as far as i can tell the only thing controlled by the feedback from the tach is the fuel cut....

Okay, I don't know why the Tach would provide the ECU with any sort of signal... Why'd they do it that way?

Do you know if the Tach alters the signal from the ignitor at all before sending it to the ECU? If not, you could supply the ECU with a signal from the ignitor. I highly recommend you use an optoisolator for this.