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View Full Version : 1994 Honda Civic VX Cranks but no spark


AskMe24
Aug 14, 2012, 11:03 PM
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

TxGreaseMonkey
Aug 15, 2012, 06:20 AM
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.

AskMe24
Aug 15, 2012, 09:26 AM
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

TxGreaseMonkey
Aug 15, 2012, 10:39 AM
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.

AskMe24
Aug 15, 2012, 11:25 AM
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

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