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IACV code and surging miss

Discussion in 'Civic and del Sol - EG and EK' started by flash3825, Aug 12, 2013.

  1. flash3825

    flash3825 New Member

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    I bought for my son a '96 Civic EX with a '92-'95 D16Z6 engine, P2P A81 ECU and an automatic transmission. The IACV wiring was converted from a 3 wire plug to a 2 wire plug and the throttle position sensor was replaced, neither one helped. I have two problems that I’m trying to solve:

    1. surging miss at 1600 RPM – just finished tune-up, plugs, wires, cap rotor and fuel filter, cleaned IACV and throttle body, replaced distributor

    2. check engine light on with one code – P1509 - IACV circuit

    Any possible solutions would be VERY appreciated. Thanks!
     
  2. 99sidude

    99sidude Moderator Moderator VIP

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    Do those cars have a fast idle thermo valve (FITV). I'm pretty sure the obd-1 cars all did. Anyways, there is a threaded cap inside the part that backs out. This doesn't let the valve close, so you get a surging idle once the engine warms up. It's an easy fix. Just pull the cap on the housing and screw the valve back in.
     
  3. flash3825

    flash3825 New Member

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    Thanks for the information. It turns out that I needed to change the IACV to the 3 wire IACV so I changed the throttle body to the '96-'00 throttle body and it had the newer 3 wire IACV. Once I wired it up the miss was gone and the IACV code was gone. I still have the CEL on and a knock sensor code because the OBD2 ECU is looking for it and my D16Z6 engine doesn't have a knock sensor. Any ideas on how I can get rid of the knock sensor code and make the cel go off? I'd prefer not to just take the light out.
     
  4. CAFROG

    CAFROG Honda Minion VIP

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    You can get a OBD2-OBD1 jumper harness and run the P28 ECU (D16Z6). But that may lead you to switching back to the other throttle body.
     
  5. flash3825

    flash3825 New Member

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    The only OBD2 to OBD1 jumper for an automatic trans available is through Rywire at a cool $250. The owner of Rywire called me and advised against the jumper and now I'm glad I didn't buy it. I have an automatic trans and I got it operating real well with a swap of ecu's (both OBD2) - the P2P A81 ECU stock. The ECU that runs everything the best is the stock OBD2 that came originally with the '96 Civic, it turned out that the ecu in it had mods but now that I have the stock ecu it works real well. The only problem left to solve is the CEL and the knock sensor code. Not too long ago a guy said I could ground one of the pinouts but I don't know how to do that and I'm afraid that might screw things up - any ideas?
     
  6. CAFROG

    CAFROG Honda Minion VIP

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    Search around ffsquad.net and they might have something.
     
  7. flash3825

    flash3825 New Member

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  8. CAFROG

    CAFROG Honda Minion VIP

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  9. flash3825

    flash3825 New Member

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    Thanks! I didn't find a knock sensor bypass trick at that site. Any other ideas?
     
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