December 2, 2015

CRX B18a1 vacuum diagram

Posted on July 4, 2010 by in In the Garage

Back by popular demand, a wiring diagram for the obd0 b18a1 in an MPFI 88-91 CRX (that’s HF and Si, not the DX).  This should also apply to EF/ED Civics, but I’m running on memory here and don’t have a car to verify this on.

B18a1 CRX Vacuum Diagram


If there are any questions or corrections (as I’m sure there will be), feel free to leave them in the comments.

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4 Responses to “CRX B18a1 vacuum diagram”

  1. Rhys 27 April 2011 at 6:06 pm #

    Is this the same as the b16a1 set up in a crx hf 89? It looks really similar, there’s a few capped tubes and pipes in the bay and i’m trying to find out what is what and whether they were done right by the previous owner.

    • Jesse 28 April 2011 at 2:41 pm #

      It’s not the same, only vaguely similar. The b16a1 intake manifold is completely different, and has fewer vacuum connections on it. I believe you want this diagram:

      • james 23 June 2013 at 3:55 pm #

        on the vacuum diagram u have one tube on the front of intake going to the iacv idle air control valve isnt this valve on the back help…
        please email me…i might send a pick

  2. Rhys 7 May 2011 at 6:06 pm #

    Awesome thank you!

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