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Anyone know if the 4+3 can be made to turn on with a separate relay aside from the factory C4 ECM/harness?
I've got a ls swap with Holley terminator x.
Yes, it can. When I switched to Holley EFI in my 85 I used the factory wiring,(keeping the switch that doesn't allow OD in 1st gear intact) added a relay, and used the switch on the console. Are you looking to put the Holley in charge of the overdrive or have manual control of it?
Yes, it can. When I switched to Holley EFI in my 85 I used the factory wiring,(keeping the switch that doesn't allow OD in 1st gear intact) added a relay, and used the switch on the console. Are you looking to put the Holley in charge of the overdrive or have manual control of it?
Yes, manual control. The EFI doesn't even know the OD exists in mine.
Which Holley are you using?
The link above mentions using the factory ecm so I’m assuming you did something different? Can I get a Barney style set of directions? Lol
Last edited by zohsixbyrd; Jun 9, 2020 at 06:47 PM.
Which Holley are you using?
The link above mentions using the factory ecm so I’m assuming you did something different? Can I get a Barney style set of directions? Lol
I'm running a Holley HP. (I would suggest the Dominator if you're planning on running boost. I ran out of IOs quick once i added the turbocharger!)
This is how my overdrive control is wired now.
I'm running a Holley HP. (I would suggest the Dominator if you're planning on running boost. I ran out of IOs quick once i added the turbocharger!)
This is how my overdrive control is wired now.
I'm running a Holley HP. (I would suggest the Dominator if you're planning on running boost. I ran out of IOs quick once i added the turbocharger!)
This is how my overdrive control is wired now.
If I’m reading this correctly there’s a black wire from the OD select switch that changes to a light blue wire which goes into the factory ECM? Since you’ve got a Holley I take it you added a pink wire in place of the LT Blue that originally went into the ECM?
If I’m reading this correctly there’s a black wire from the OD select switch that changes to a light blue wire which goes into the factory ECM? Since you’ve got a Holley I take it you added a pink wire in place of the LT Blue that originally went into the ECM?
It's been a while since I worked it but I believe the black wire changed to light blue. The pink wire is just the 12v + constant with ignition in start and run. I had plenty of those left over from the factory ECM harness when I stripped it. I would check a wiring diagram for your year if it isn't an 85 though.
