I have a customized 4runner that came from warmer weather, so the previous owner had the CSI eliminated. Most of the engine/ECU wiring is custom some of the stock harnesses were eliminated. I would like to wire a CSI in the simplest way as I can't fully rely on the stock wiring schematics. I know the CSI needs 12v from the starter and needs to be grounded when the timing switch is within the cold temperature range. What's the simplest way to wire a new CSI so I can get better cold starting?

 

Do you have the CSI? Do you have the Cold Start Injector Time Switch? That's all you need.

Trying to wire the CSI without the CSI Time Switch could be very disappointing. It not only senses temperature to determine whether to open the CSI, it also limits the CSI open-time no matter how cold it is. Without it, half the time you'll just flood the engine, risking a fire in the exhaust system.

 

I have both the CSI and the timing switch. From some other posts I read, it looks like the second terminal on the switch connects to something that cuts the injector off after awhile to keep it from squirting fuel too long. What should I connect that terminal to? I think it's called STJ 2 in the manual.

 

Yeah, just like the diagram shows. The CSI is turned on by the STA line to the starter solenoid, grounded through STJ at pin 2. STA on the timer runs a heater that opens STJ (shutting off the CSI) after a (short) temperature-dependent time.

 

what that all means in scope103's post is that the CSI only operates below a certain temperature and if the key is in the "start" position. it doesn't spray fuel when the key is in the "on/run" position, ever. and if the ambient temperature is above whatever the STJ opens at, it won't spray even if the key is in the "start" position.