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HeadlesNorseman · 03-28-2014, 05:13 PM

This is just some basic question/theory i have regarding an injector cut off switch.

The car is a 1990 civic, with the throttle body DPFI injection

Disclaimer: i am very experienced with automtive/especially honda wiring, so im not scared and i can diagnose and fix anything i mess up

Question on theory: I assume fuel injectors operate by recieving a 12 volt positive signal, constant, and the ECU then switches the ground as its pulse width mod. Interupting which one of these would be best? how many amps are used to operate the injectors? i have a 30a relay and a 20a switch wired up and ready to go. This is where im stuck!

My car only has 2 injectors, like a 2 barrel carb: a constant and a "full throttle" injector

Now... each injector has 2 wires listen in its ECU pinout, but i can not figure out which is which. they just say A5 manin injector with A7.

It is my understanding that if you cut off this signal, the ecu does not like it very much. And with personal experience, it DOES NOT like the key being switched off. Will be hard to restart, CEL, and erratic idle for a moment.

The real question, do i interupt the ground for the injectors, or the constant 12 volt signal? and do i want to do this at the injector itself or at the ecu?

03-28-2014, 05:13 PM	#1 (permalink)
HeadlesNorseman Honda Head Join Date: Feb 2014 Location: nj Posts: 20 Rescue Toaster - '90 Honda Civic 90 day: 40.92 mpg (US) Thanks: 2 Thanked 5 Times in 4 Posts	Wiring an injector cutoff switch This is just some basic question/theory i have regarding an injector cut off switch. The car is a 1990 civic, with the throttle body DPFI injection Disclaimer: i am very experienced with automtive/especially honda wiring, so im not scared and i can diagnose and fix anything i mess up Question on theory: I assume fuel injectors operate by recieving a 12 volt positive signal, constant, and the ECU then switches the ground as its pulse width mod. Interupting which one of these would be best? how many amps are used to operate the injectors? i have a 30a relay and a 20a switch wired up and ready to go. This is where im stuck! My car only has 2 injectors, like a 2 barrel carb: a constant and a "full throttle" injector Now... each injector has 2 wires listen in its ECU pinout, but i can not figure out which is which. they just say A5 manin injector with A7. It is my understanding that if you cut off this signal, the ecu does not like it very much. And with personal experience, it DOES NOT like the key being switched off. Will be hard to restart, CEL, and erratic idle for a moment. The real question, do i interupt the ground for the injectors, or the constant 12 volt signal? and do i want to do this at the injector itself or at the ecu?