[davin]

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 :-/

[TxGreaseMonkey]

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 pressure 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.

[davin]

Do I have to find someone to crank the car while I do this or can I just turn the ket to the couple clicks ahead?

[davin]

I suspect your ECM is bad. Run this simple 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 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?

[davin]

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?

[TxGreaseMonkey]

Yes, you have to disconnect the negative battery terminal or you can wreck the ECM.

Only replace the MAP Sensor as a last resort because they usually are very reliable and they cost $225. I ended up buying a new one.

[TxGreaseMonkey]

do i have to find someone to crank the car while i do this or can i just turn the ket to the couple clicks ahead?

I not sure of your question.

[TxGreaseMonkey]

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 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.

[davin]

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 :-/

[davin]

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 :-/

[davin]

The thing that really stinks about this is, I have only had it about a week before it crapped on me. I bearly gave it any love :-(

[TxGreaseMonkey]

The main relay controls power going to the ECM.

http://www.tegger.com/hondafaq/mainr...mainrelay.html

[TxGreaseMonkey]

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 :-/

When you checked for 5 volts between D19(+) and D21(-), did you have the rest of the harness connected to the ECM and the negative battery terminal connected, the ignition ON, and testing at the "male pins" on the ECM (not on the D connector)?

[TxGreaseMonkey]

The solution is going to be something major, not some remote "possibility." The Check Engine Light has to go out for your Civic to start. If it stays on, then there won't be any spark. Likewise, a dead main relay = no spark. I still think the Check Engine Light won't go out because the ECM is bad.

Again, if the CEL will not go out, check the ignition switch, main relay or ECM.

[TxGreaseMonkey]

Two additional things to check:

. All under-hood and under-dash fuses. Use your DMM. Pay particular attention to under-hood fuse #31, which is a 7.5A fuse to the ECM. There are four fuses in a row, along the back of the fuse box. This one is located second from the left and, if removed for 10 seconds, will erase any stored DTCs and reset your ECM.

. Main ECM ground. As mentioned above, it is located on the thermostat housing. Remove and examine the 3-wire brass ground, clean with 240 grit abrasive cloth, and apply dielectric grease.

To recap, you replaced the distributor (remanufactured), which had new igniter, coil, and sensors; the main relay (Honda); and the ECM (used)? Or, did you return the distributor to Autozone, since it didn't solve the problem?

[davin]

Two additional things to check:

. All under-hood and under-dash fuses. Use your DMM. Pay particular attention to under-hood fuse #31, which is a 7.5A fuse to the ECM. There are four fuses in a row, along the back of the fuse box. This one is located second from the left and, if removed for 10 seconds, will erase any stored DTCs and reset your ECM.

. Main ECM ground. As mentioned above, it is located on the thermostat housing. Remove and examine the 3-wire brass ground, clean with 240 grit abrasive cloth, and apply dielectric grease.

To recap, you replaced the distributor (remanufactured), which had new igniter, coil, and sensors; the main relay (Honda); and the ECM (used)? Or, did you return the distributor to Autozone, since it didn't solve the problem?

I still have the remanufactured dizzy along with a new cap/ rotor with new plugs, the working ECM from a wrecked civic, a new main relay from OEM Honda and still the CEL light stays on and there are still no clicks from the main relay and everything is installed correctly.

I used the fluke to get a reading from the 3 pin MAP sensor connection D19 (yellow/ green) and D21 (green/ blue) and had no signs of a reading when the ignition was on, but not cranked. I don't feel comfortable cutting the wires from the D-Harness (looking at the ECM, the D-Harness is the mid size connector and D19 & D21 are the two most top right connections all the way at the end).

I really do not think the ECM is bad because I have two P06 computers that both register the same results. I also talked to several other people that I work with in the navy to see if not disconnecting the battery would short the computer, people said it was highly unlikely. Another person, a highly skilled aircraft mechanic that does inspections for quality assurance (these are the most knowledgeable people mind you) and he said he fixed his accords ECM and dizzy without disconnecting the battery and it worked.

Also the engine is TDC (top dead center), meaning that the cams line up with the piston... and since the cam is keyed to the dizzy (distributor), it will fire in the correct order (unless you have your spark plugs all backwards and won't fire right). Furthermore, the valvetrain does move when I crank it from taking off the oil cap and looking for the valvetrain to move when cranked.

I am bringing along an aircraft electriciansmate with me to look at my car. This is way beyond my level of electrical engineering and see if his professionalism hands on will do. Also, I will take off all the grounds and take a wire brush to all the connections to see if that will help. Also I will disconnect the battery and reconnect all the connections that I have touched, also checking all the fuses, do all the groundings as stated above, reconnecing the battery and see if that will do anything. I need this car by tonight because I have class to go to and I need college in me to keep me out of trouble :-/

I really appreciate all your help and I tried applying all my knowledge and processes in case people try and Google this with a no start, no spark problem from a Honda Civic.

[davin]

After talking with the aircraft electrician, he said it sounds like a ground issue somewhere. Especially if when I purchased a new dizzy, it fired up and the next day it didn't. Then going back to autozone for an exchange to only crank again. So we are going to do that and also the fuses while the battery is disconnected. Hopefully that will help.

[davin]

I also did not see an alarm that turns off the ignition anywhere, so I ruled that out as well. Also noted, they said not disconnecting the battery would not short out my ECM.

[TxGreaseMonkey]

You have had some introduction to Honda Civics. In my mind, your Civic should run. Apparently, you have an "open" somewhere or the ignition switch is bad and the ECM is not getting power. Thanks for your response, professional attitude, and service to your country. God bless.

[TxGreaseMonkey]

The D-Harness is the molded connector on the right with 22 sockets.

.. .
.. .

As you look at the pins on the ECM, D19 and D21 are the last two pins on the bottom row.