This may be a loaded question to some, but hopefully not to at least one person. Long story short, car has been up on Jack stands for 2 years due to life, work, etc. I'm 95% done with the upgrades, maintenance, etc, and doing the wiring inside the car now. I decided to pull all the wiring out for the gauges, alky, scan master, and start new. Everything is accounted for qith the exception of one wire tapped into the ecm, yellow with black wire, electronic spark control signal. The tach gets its signal from under hood, and I've not wired the boost controller yet. I can't for the life of me remember why I'd need this reference. Any ideas??