B16A OBD1 interior wiring options??

[Dutchy1978]

I am based in Melbourne Australia and struggling to find an interior loom that goes from the instrument cluster to ECU and through the bulkhead/firewall that is for Vtec & OBD1. (92-95 EG civic)
I am doing a Vtec conversion into a mini and already have the JDM B16A engine and engine wiring and P28 ecu (chipped) so just want the matching harness.
A few people have offered me the Integra DC2R harness with OBD2A and said to use the OBD1 to OBD2A adapter but I am unsure if it will work with my JDM Civic cluster and ECU.
Has anyone done this and was it difficult to make it work?
Or do you have another option that will do what I need?
All help is appreciated.

[ECU-MAN]

Either loom will do the job.


You need to identify the wires in the OBDI harness that go to the dash loom and strip the PGMFI components from it. Once you remove the PGMFI loom from the dash loom you will find you will have a handful of wires that need to be wired up to get the ECU working, all other bits will be connected at the LH Shock tower connectors, the RH Sock tower connectors also has two connectors that need to be wired.


OBDIIA or OBDI will have no impact on wiring as the effort will be the same however an OBDIIA EK4 loom will be 1 piece without any LH side shock tower connectors, the green connector that connects to the cabin loom simplifies the install.






good luck with it

[mocchi]

obd2a to obd1 conversion harness.
not obd1 to obd2a.

[Dutchy1978]

obd2a to obd1 conversion harness.
not obd1 to obd2a.

Sorry. that is what I meant.

[Dutchy1978]

Either loom will do the job.

You need to identify the wires in the OBDI harness that go to the dash loom and strip the PGMFI components from it. Once you remove the PGMFI loom from the dash loom you will find you will have a handful of wires that need to be wired up to get the ECU working, all other bits will be connected at the LH Shock tower connectors, the RH Sock tower connectors also has two connectors that need to be wired.

OBDIIA or OBDI will have no impact on wiring as the effort will be the same however an OBDIIA EK4 loom will be 1 piece without any LH side shock tower connectors, the green connector that connects to the cabin loom simplifies the install.

good luck with it

Sorry if I am a bit confused.
1. So you are saying to remove the PGM-FI wires from my current B16A OBD1 engine wiring loom? Or from the OBD2A dash loom?

2. Does the OBD2A dash loom go through both sides of the firewall and connect to the engine loom? You mention not on the LH side?
3. Do the OBD2A shock tower plugs match the OBD1 engine loom plugs?
Sorry for all the questions but I can't seem to find a wiring diagram for both the OBD1 & OBD2A wiring to work it out for myself.

Cheers.

[dorikin]

I think ECU-MAN is assuming you will be stripping the interior loom down to the bare essentials for the mini. i.e,. just use PGMFI wires from the DC2R dash loom
But it sounds like you want the whole shebang to wire up a working honda cluster, etc

1. I believe he was referring to the OBD2a dash loom - but depending on what you want it may not be the best option
2. Yes through both sides of firewall, although RHS can be unplugged at underdash fusebox
3. I might have the diagrams somewhere but they should be the same - i'll have a look when i have time

If you open you scope up to non-vtec OBD1 dash looms you should be able to find one quite easily. example: GLi, Si models both hatch or sedan
You would only have to wire in a couple wiress from LH shock tower to ECU plugs
I've also heard somewhere through the grapevine that all 92 models came pre-wired with vtec

[Dutchy1978]

Thanks Dorikin. Makes sense. Yes I am using the Civic cluster so wanted it to be plug and play and then I can just cut away the rest of the wires.
As you mentioned, I think the best option is to go with a non Vtec civic dash loom and add the 3 wires from the shock tower to the ECU.
Thanks heaps.

Next Question..... Does anyone have a cheap Civic OBD1 dash loom (non Vtec) for a manual trans they want to get rid of? I would also like the fuse box and relays attached if possible.

[dorikin]

just make sure you get one from an EFI model not carby.

might actually be more than 3 wires for OBD1, off the top of my head:
1. VTEC solenoid
2. VTEC pressure switch
3. Knock sensor
4. O2 sensor heater

[Dutchy1978]

Yes correct although don't need the knock sensor as my P28 ECU with chip doesn't have the knock board.
O2 sensor has 4 wires too. Will that need to be wired into the basic loom?

Is there such a thing as an OBD1 loom for carb? I wouldn't have thought so unless it is a Honda thing.

[ECU-MAN]

Dorikin has pretty much filled in the blanks.


Not all post 92 looms are VTEC wired. Si and VTi only are.


Carbie looms where more OBD0




Unfortunately what your trying to achieve will not be plug and play, it is going to require some wiring.

[Dutchy1978]

Thanks for the feedback ECU-MAN. I didn't think OBD1 would be carb although you just never know.
In terms of plug and play I just wanted the cluster, ECU, and tower plugs to plug into the factory loom and the rest I would customise to suit my build. I currently run a fully programable Autronic SM4 ECU which I wired up myself so I have no issues with custom work.
This build is going to need engineers sign off to keep it road legal so wanted as much standard Honda gear as possible to get sign off.

quick question, if I can't find a civic loom and have to get an Integra will the cluster plug fit straight into the Civic cluster and be pinned the same?

[dorikin]

nope, cluster plugs are definitely different

[Dutchy1978]

Good to know. That limits my options for what I am after then.
I'll just look for the civic one only and modify / add relevant Vtec wires.
Cheers