Hello! I have inherited a distant relative’s 1985 IROC, which was originally a 305 TBI with a 5 speed. Along the way, the original engine was swapped with a spicy Gen 1 350 SBC, a Powerjection IIi TBI, and then eventually all engine management was moved to a Holley HP. Unfortunately, since the relative is deceased, I don’t have the luxury of asking him details about his project car.

I have it up and running, idling well, etc., but I have no idea what, if any, the original ECU is still doing. I know it has no part currently in the active engine management, but does the original OEM ECM run / control anything else in the car? I notice that the car needs both a key in the ignition (turned to run) PLUS a manual push button to engage the starter. Is there some sort of interlock with the factory ECM that made the necessary?

Related, and what got me thinking about the OEM ECM in the first place, is I am wondering if I can detail the VSS signal coming out of the speedometer as a speed input on the HP.

 

You can throw that ECM in the garbage where it belongs. As for your speed input into the HP I believe it can be done you'd be better off checking out the Holley forums for that. Danny is the man over there and will get you sorted out real quick

 

Ha! Awesome. Thanks for the advice. I got a space in the “f*ck it bucket” ready for it.

 

Good to know as Im switching to Holley Terminator X as well.