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-   -   1994 Honda Civic VX Cranks but no spark (https://www.askmehelpdesk.com/showthread.php?t=693898)

  • Aug 14, 2012, 11:03 PM
    AskMe24
    1994 Honda Civic VX Cranks but no spark
    New rotor, cap, plugs, wires, main relay, ign coil checked with new, all fuses OK. NO check engine light ever (bulb checked to be OK) or 2 sec running of main fuel pump (which works when powered directly to battery). Car ran fine, just wouldn't start next day. No spark. Is ECM possible culprit? Wouldn't main relay still power the pump for the 2 seconds or does ECM control that through main relay?

    Thanks
  • Aug 15, 2012, 06:20 AM
    TxGreaseMonkey
    The ECM failed. Disconnect the negative battery cable, remove the old ECM, and record the Honda Part No. Install a new ECM with an exact Honda Part No. match. Shop for price and warranty.
  • Aug 15, 2012, 09:26 AM
    AskMe24
    Thanks for the quick response on my 1994 Civic VX no spark problem.

    One more question, as once I purchase the ECM for $300 I own it: does the main relay rely on the ECM to tell it when to power the fuel pump for the 2 sec cycle or is the timing mechanism solely in the main relay?

    Thanks again
  • Aug 15, 2012, 10:39 AM
    TxGreaseMonkey
    Yes, the main relay grounds through the ECM. Therefore, when the ECM is bad, the main relay won't work properly and the fuel pump won't run.
  • Aug 15, 2012, 11:25 AM
    AskMe24
    Quote:

    Originally Posted by TxGreaseMonkey View Post
    Yes, the main relay grounds through the ECM. Therefore, when the ECM is bad, the main relay won't work properly and the fuel pump won't run.

    Mr. GreaseMonkey: this is a classic. I have been missing the CEL light even when the key is first turned on. That is part of my confusion. I have been told the ECM has an external light that will indicate failure codes. In looking for the ECM to check that I discovered that IT IS NOT THERE. Just a loose wiring harness and the mounting hardware. The car had been stolen months ago, has run fine for a month (actually started getting better gas mileage), and then just wouldn't start. I changed all the locks after the theft, no sign of a recent break in. Could the car possibly run at all without an ECM? Or have we had another break in the night before it stopped working?

    I'm not joking, but I am laughing.

    Please let me know. I've learned so much about Honda ignition systems.

    Thanks
  • Aug 15, 2012, 11:32 AM
    TxGreaseMonkey
    To test your ECM, then, perform the K-Test. Do a search for it. The car can't run without the ECM.

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