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naval aircraft mechanic cannot get his car started
So I bought a 1992 honda civic DX auto and after a week of buying it, it crapped out on me. it would crank, but would not fire up. Immediately I began troubleshooting. I checked for spark and there was none when I grounded the plugs against the frame several times while my friend cranked it. Next I checked for fuel to the fuel rail, there is fuel flowing when cranked. also, my valvetrain moves when cranked so my belt is not broken. everything is connected also.
There was no spark so I replaced it with a new distributor from autozone and it started right up after one crank. The next day I went to start it, and continued like last time; just cranked and would not fire. I exchanged the part from autozone and it still would crank, but not fire up.
I went to ebay and purchased an ECU from a good working Civic DX automatic that was wrecked. The sellers feedback was 100% and assured me the ECU is in working order. Still nothing, just the solid CEL with no clicking from the main relay whatsoever.
Next my determination was the main relay. I had all the diodes soldered and put back in, still nothing. next I went to Honda and purchased a new main relay with the part numbers matching and it still would not click.
All the grounds are secure and ground properly from the ground wires (the tranny ground, the battery ground and also the engine ground from the valve cover), I get 12v from the battery and I cannot determine what is wrong with my civic. I really need to get this car running and I have spent $500 so far and I am at a total loss and I have no where else to turn. I am an aircraft mechanic for the Navy so I have a good comprehension as to what I am doing. Please help :-/
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.
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 bad. Remember, the ECM is nothing but a giant "power transistor," whose job is to provide the proper voltage to a host of sensors (transducers) under constantly changing conditions.
i also read your other informative post about how your car did not start because of your map sensor. i was thinking it could have been this. did you buy a new one or was it just the connection?
crap, stupid me just realized that i never disconnected my battery when i swapped ECU's... do you think i fried the working ECU when i connected it to the harness?
Once you get your Civic running again, be sure to change all of the fluids. I would use Valvoline SynPower Brake Fluid and flush the whole system. Also, I would take a battery squeeze bulb and partially replace some the the power steering fluid. I would also drop and clean the transmission pan, change the filter, and replace fluid with either Mobil 1 Multi-Vehicle Synthetic ATF or Amsoil Universal Synthetic ATF. I believe your Civic requires a Dexron II rated fluid. I run Mobil 1 5W-30 synthetic engine oil with a Purolator PureOne filter in my 1993 Civic DX. Finally, I would change the antifreeze with a 50/50 mixture of antifreeze and distilled water. A well-maintained Civic can last 350,000 miles.
so after doing all that, there is absolutely no power coming from d19 and d21 nor is there any power from the map sensor wires to the ground connecting to the tranny. i have swapped out both ECUs that are compatible with my car furthermore.
my assumption is that there is no power going to the ECM, but the strange thing is that there is 12v coming from the battery.
it is not the dizzy because the complete unit was replaced along with a cap and rotor with spark plugs and all.
i am in the barracks with an aircraft electriciansmate and he cannot find anything either :-/
i am not getting power to terminals d19 and d21 nor am i getting power from the map sensor to the ground running from the tranny. however i am getting a full 12v from the battery.
my conclussion is that there is no power running to the ECM :-/
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