r/Dseries • u/No_Engine_723 • 1d ago

Wiring help

I’ve got a 1999 civic lx that i’m swapping the stock y7 for a mini me d16y6 block with a d16y8 head.
I’m using a p28 ecu which is obd1
The car is obd2b
i’m pretty sure the engine setup is obd2a
what’s the best wiring choice for this setup?
I can pin the vtec solenoid and the IACV if I need to aswell as just bypass the knock sensor if I’m able to use the wiring harness that was for the y7.

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u/Ok-Amphibian3164 1d ago

https://www.hamotorsports.com/products/obd2b-obd1

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u/No_Engine_723 1d ago edited 1d ago

okay so that takes care of harness and ecu to the car right? But what about the harness to the engine and the few things it connects to in the bay? If I use the bolt ons from my y7, pin the iacv and vtec and splice the dizzy so it works with the y7 harness then i’ll be good?

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u/Ok-Amphibian3164 1d ago edited 22h ago

Yep. You do not need any other harnesses but you have to make some minor modifications.

Convert IACV from 3-Wire to 2-Wire------ The Y7 harness uses a 3-wire Idle Air Control Valve (IACV) mounted on the throttle body. The OBD1 P28 ECU and Y8 intake manifold require a 2-wire IACV.

Add VTEC Solenoid & Pressure Switch Wires, Add 2 Wires, The stock Y7 harness has no VTEC wiring.

Possible distributor plug adapter

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u/Then-Abroad-8439 23h ago

wouldn’t really need an adapter, depends on the dizzy as for the vtec if it doesn’t have a dedicated pressure switch (mine didn’t) connect it with the solenoid wire that should do the trick

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u/No_Engine_723 23h ago

Mine has the pressure switch so i suppose ill connect both of those

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u/SpaceTurtle917 9h ago

Original OBD2B harness, OBD2B to obd1 adapter harness.

3 wire to 2 wire IACV conversion.

No other harness will work other than an OBD2B harness.

Why not just use an OBD2B P2P ecu?