94 civic no ignition power
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Junior Member
Joined: Aug 2011
Posts: 1
94 civic no ignition power
no spark nor does cluster lights come on when key turned over all fuses good and just bought a new main relay didnt change anything cant figure out y. I have fuel on but thats it and it will turn over. I have swaped an f20 b in I put old wire harness back in and still get nothing it worked when I didnt have a motor at all in it and now I got nothing
HCF Member
Joined: Sep 2005
Posts: 906
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I found this interesting block of advice:
If you turn your ignition ON, the Check Engine Light, on a properly running Honda, should come on and then go off after 2 seconds. During this time, you should hear the fuel pump run. If the Check Engine Light does not come on and then go off, focus on the main relay, ECM, and ignition switch.
My hypothesis is that your ECM is bad. Run a simple "K-Test":
Disconnect the MAP sensor connector from the MAP sensor. Turn ignition ON and check for 5 volts between the right female reference wire socket (+) and the main ECM ground on the thermostat housing. Really press the black test lead into the ground. If you don't have approximately 5 volts, then your ECM is likely bad. Remember, the ECM is nothing but a giant "power transistor," whose job it is to provide the proper voltage to a host of sensors (transducers) under constantly changing conditions. The confirming test is to turn the ignition switch OFF, disconnect the D harness to the computer, turn the ignition switch ON, and measure the voltage between computer pins D19(+) and D21(-). If there is less than approximately 5 volts, substitute a known good ECM. If you have approximately 5 volts between D19 and D21, repair an open between the ECM and YEL/GRN reference wire going to the MAP sensor.
Most of these "crank but won't start" situations on Civics are main relay, ICM, coil, or ECM related. A few have been caused by bad CYL, CYK, or TDC sensors in the distributor. If your ECM checks out OK, then I would suspect your ICM (igniter), since you just installed a new main relay. A final item to check out is the Manifold Absolute Pressure (MAP) Sensor, which is the "key" sensor on Hondas. It controls timing (similar to the old vacuum advance on distributors) and air/fuel mixture, depending upon manifold presure changes. Like any transducer, it converts energy from one form to another. Here, it converts throttle body vacuum pressure changes into fluctuating electrical current signals to the ECM. If this sensor does not receive the proper voltage from the ECM, you will experience catastrophic ignition and fuel system failure.
My experience with Hondas has been main relays, ICMs, coils, and ECMs should be replaced proactively after 10 years or 120,000 miles, whichever comes first. Distributor bearings will likely fail around 95,000 miles.
My hypothesis is that your ECM is bad. Run a simple "K-Test":
Disconnect the MAP sensor connector from the MAP sensor. Turn ignition ON and check for 5 volts between the right female reference wire socket (+) and the main ECM ground on the thermostat housing. Really press the black test lead into the ground. If you don't have approximately 5 volts, then your ECM is likely bad. Remember, the ECM is nothing but a giant "power transistor," whose job it is to provide the proper voltage to a host of sensors (transducers) under constantly changing conditions. The confirming test is to turn the ignition switch OFF, disconnect the D harness to the computer, turn the ignition switch ON, and measure the voltage between computer pins D19(+) and D21(-). If there is less than approximately 5 volts, substitute a known good ECM. If you have approximately 5 volts between D19 and D21, repair an open between the ECM and YEL/GRN reference wire going to the MAP sensor.
Most of these "crank but won't start" situations on Civics are main relay, ICM, coil, or ECM related. A few have been caused by bad CYL, CYK, or TDC sensors in the distributor. If your ECM checks out OK, then I would suspect your ICM (igniter), since you just installed a new main relay. A final item to check out is the Manifold Absolute Pressure (MAP) Sensor, which is the "key" sensor on Hondas. It controls timing (similar to the old vacuum advance on distributors) and air/fuel mixture, depending upon manifold presure changes. Like any transducer, it converts energy from one form to another. Here, it converts throttle body vacuum pressure changes into fluctuating electrical current signals to the ECM. If this sensor does not receive the proper voltage from the ECM, you will experience catastrophic ignition and fuel system failure.
My experience with Hondas has been main relays, ICMs, coils, and ECMs should be replaced proactively after 10 years or 120,000 miles, whichever comes first. Distributor bearings will likely fail around 95,000 miles.
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