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85 CRX to CVCC wagon swap wiring harness ?

Discussion in 'HYBRID -> ED-EF / DA' started by semlin, Oct 12, 2005.

  1. semlin

    semlin Junior Member

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    Hi, I hope you can help out a newby with some questions on an older civic swap.

    I have the mechanical part of a motor/tranny swap done between 1985 CRX DX and a 1985 Civic Wagon DX that had the CVCC vacuum system. The mechanical swap was fairly easy but the wiring harnesses do not match. I am looking for some help/suggestions on how to deal with that.

    First, is it is possible to just swap the old wiring harnesses over and plug the donor crx harness into the wagon plug receiver in the dash or would I need to change out the plug receiver? If so, do you feed the dash plugs through the firewall or pull the harness out of the engine bay through the firewall?

    If not, I assume I have some splicing or extra wiring to do. If I need to splice and rewire, can I just look for wires in the harness that are the same colour as the donor connectors and tape off unused wires? Can I leave sensors I do not need any more unplugged or do I need to pull the harness plugs at the dash?

    I have the wiring diagrams from the Haynes manual which are nearly useless.

    The wiring harnesses line up except for these things (I may have missed one or two)

    1. the vacuum boxes on the rear firewall are different, and the harness connectors don't match.

    2. there is a connector plug for a vacuum box on the DS that will now dangle because there is no vacuum box anymore.

    3. the carb sensor wiring is different and the harness connectors don't match.

    4. there is a sensor plug on the old motor right beside the oil pressure sensor on the back of the block. the new motor does not have the sensor so I have a dangling connector.

    5. the old carb had an autochoke, the new carb does not. I am installing the manual choke from the donor car into the wagon. The manual choke has two wire connectors at the dash and I can't find equivalent loose wires in the wagon. Is this just for the choke dash light or does it notify any sensors?

    6. the old motor had an 02 sensor in the exhaust manifold, the new one does not.

    thanks in advance for any suggestions or help you can offer
     
  2. Celerity

    Celerity Well-Known Member

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    1: Use the original "Vacuum box" that came with the chassis
    2: I'm confused by this one
    3: Can't you use the original carb with the new head and motor ?
    4: Sounds like the knock sensor.
    5: I have a feeling the new motor is a warm-weather motor. Like a filipino (Although I'm sure it's not) and wasn't meant for the climate. My personal thing, I would continue working the manual choke in. The other choke will require the replacement of the carb, because chances are the choke butterfly is sealed on the carb you currently have
    6: No 02? at all ? This motor now sounds like it may be some strange federal emissions, or high altitude emissions car. Can you take pics of the the Vacuum wiring (Top of the engine bay) the intake runners, and this "vacuum box" you're talking about ?

    -> S
     
  3. semlin

    semlin Junior Member

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    thanks a lot for the comments. now you have me worried. I thought I was switching two stock setups and things would be plug and play

    1/2/3 ok, the wagon had the CVCC system which is a spaghetti dinner of dozens of vacuum hoses with two vacuum boxes, one on the firewall and one on the DS fender wall right beside the timing belt cover. The CRX donor had a single smaller vacuum box on the firewall and a much simpler system of vacuum hoses. I am sure it is original because the harness is original and not spliced and has a different connector plug from the wagon for this vacuum box and far less wires. I could not use the CVC system unless I switched the intake and carbs over (the CVCC system takes extra vacuum lines off the intake and the CRX also has no EGR so I would have to change intakes). I made the decision not to do that when I pulled the motor and did not label the old vacuum hoses. It would be major work to redo now but I guess it's possible. I figured switching or splicing the harnesses would be less work and since the CRX was running nicely, why mess with a good thing. Is the harness swap really unrealistic?

    4. thanks. I'm surprised to see a knock sensor in a car with no ecu. does it retard the timing somehow or enrich the mixture? the distributors looked identical and so did the wire connectors so I kept the CRX one on the block. I will have to look at whether Honda has leftr a removable plug or bolt on the CRX block where this sensor goes.

    5. The CRX donor motor does not match the # on the chassis and it might be modified or an import. I guess someone might have desmogged it as well. The block looks just like the wagon block except for the differences noted, and I actually switched the trannies and saw no difference there either.

    6. there is no hole in the exhaust manifold for an o2 sensor in the CRX. I was actually more confused by the one in the wagon since I thought only fuel injected vehicles with an ECU used an o2 sensor.
     
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