Main question: What's the easiest way to disable spark and fuel? Let's say you're doing a compression test.

Secondary questions: When would you want to disable either one or the other system? Let's say you want either the fuel injectors clicking or test the ignition system. What would you do to disable either (one or the other, not both) system easily?

 

unplug the CAS and the ecu won't do spark OR fuel, because it won't see any RPM.

unplugging the circuit opening relay (under the dash) just disables the fuel pump, but the ECU is on, sees RPM and fires the coils, which is nice if its flooded.

pulling the main fuse i think just cuts power to the ECU altogether (not sure, its more work than unplugging the circuit opening relay)

 

i always go for the EGI, some cars it's a pain to reach the CAS connector and you can only mess with that plug so many times before you develop problems with it.

 

/\..this
that clip can only get bent back so often before it ends up crumbling.It is 20 years old..

 

the clip isn't so much the problem but the tiny 18 gauge wires are, seen them snap off more than a few times. the CAS connector itself is one of the most bulletproof on the engine harness.

 

Run a relay between the 15A engine fuse and the main relay with a toggle switch. Cuts power to ecu, coils, and injector. Its a nice kill switch. EGI fuse will do the same since it feeds power into the main relay, atleast on the S5 it does.

 

Add starter only button, even put it under the hood if you want. Best thing I ever did to my race car.

 

Thats the truth right there!