rusefi.com

I've recently purchased a rusUltra affordable ECU to put on my '97 Toyota 5VZ-FE that I'm putting a turbo on, and I'm having some trouble getting it to work, trying to use it as a piggyback system. I've connected coolant temp, intake temp, throttle position, and crank position sensors, which are all still hooked up to the stock ECU. I am just sharing the signal with the rus ECU. I've completely disconnected all injectors and coils, and they are running straight to the rus ECU. With the rus ECU hooked up, I cannot get the engine to start. I've looked over the settings on the tune and all seems right. This is my first time using a system like this, so any advice would help.

It's your Coolant Temp Sensor. Your factory ECU has a pull-up resistor, creating a voltage divider with the sensor. The UAEFI has a 2.7k pull-up resistor built into it as well. The voltage is too high now. If your temp gauge is tied to the ECU, you will probably see unreasonable values on it. Disconnect the CTS wire from the UAEFI to verify.

Would it be easier just to use a separate temp sensor instead

You could do that. If your factory CTS still serves a purpose on your factory ECU, you can remove the resistor from the UAEFI board. Look here:
https://rusefi.com/forum/viewtopic.php?f=17&t=2806

Ok I will do that thank you for the help. Do you know any one how does remote tuning?