Help . My Efi Honda Civic 93 have a problem during start up, every time I shut off the engine for 30 minutes or more, and then I try to start it up, the CEL lights up for more than a minute or so. Obviously I can't start my car unless the CEL has turned off, it's very uncomfortable, especially when I'm in a hurry. I've already tried the following:

1. changed my main relay, it's brand new now
2. checked the fuses
3. cleaned the battery terminals and bought new clamps. Tightened it already.


Help please, it's very annoying! Thank you very much in advance.

Can you verify if the fuel pump is running during this entire time also please, you should hear it start up when the light comes on, it is supposed to stop in 2 or 3 seconds. The computer is the only thing that controls the CEL for this initial key on timeframe. Clean the main ground at the thermostat housing, it will be a few black wires going to a single ground terminal.

Run the K-Test on your ECM, after cleaning the 3-P main ECM ground on the thermostat housing.

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (not start). Using a multimeter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it's probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate.

It's likely a bad ECM. Look for a remanufactured ECM, with a lifetime warranty (O'Reilly Auto Parts). If necessary, based upon K-Test results, here's how to replace the ECM:

https://www.askmehelpdesk.com/cars-t...tml#post235038

Quote:

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Originally Posted by Duane in Japan

Can you verify if the fuel pump is running during this entire time also please, you should hear it start up when the light comes on, it is supposed to stop in 2 or 3 seconds. The computer is the only thing that controls the CEL for this initial key on timeframe. Clean the main ground at the thermostat housing, it will be a few black wires going to a single ground terminal.

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Yep the fuel pump is working fine, I'll try the mainground cleaning tomorrow. Thanks:)

Quote:

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Originally Posted by txgreasemonkey

Run the K-Test on your ECM, after cleaning the 3-P main ECM ground on the thermostat housing.

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (not start). Using a multimeter, check for 5 volts going between the MAP Sensor connector's reference wire (+) and ground. As you look at the connector, this is the socket on the right. Really press the black test lead into a cleaned main ECM ground on the thermostat housing. If the voltage is low, it’s probably indicating ECM failure. Most failed ECMs will record a fraction of a volt. To me, the K-Test is simple, elegant, and accurate.

It's likely a bad ECM. Look for a remanufactured ECM, with a lifetime warranty (O'Reilly Auto Parts). If necessary, based upon K-Test results, here's how to replace the ECM:

https://www.askmehelpdesk.com/cars-t...tml#post235038

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Will try that too sir kudos :cool:

I understand that the fuel pump shuts off after the first few seconds but the CEL stays on for some time still. This is with the initial key on and engine off.

Quote:

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Originally Posted by Duane in Japan

I understand that the fuel pump shuts off after the first few seconds but the CEL stays on for some time still. This is with the initial key on and engine off.

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No the CEL stays on for 30 secs or more without a click, my mechanic found the problem, it's a dying computer box:(

If your, or your mechanic, used the K-Test to identify a bad ECM, could I get you to update the K-Test Poll below?

https://www.askmehelpdesk.com/cars-t...ht=k-test+poll

Poll updated ;)

I have a 1995 Honda Civic EX, 1.6 L with 80,000 miles. I am having the same problem with my check engine light (CEL). Sometimes the CEL goes out right away other times it takes longer. Once it goes out I hear the relay and fuel pump and it starts right up and runs fine. I recently replaced the Electronic Control Module (ECM) with a used one because mine was stolen again! I suspect this could be the problem – a couple weeks later was when I started having the problems. Anyway I tried the K test and it showed 4.9 volts (I think I did it right) although I just ground it to engine block. I don’t see where the ground from MAP sensor connector is connected. Do you know which colored wire from the connector you tested? I want to make sure.

Also can you give more clarification on your confirming test:

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 the reference wire going to the MAP Sensor. After much experience with the K-Test, I wouldn’t bother running the confirming test anymore.

Where do I find reference to where the D harness, D19(+) and D21(-) pins are? I am not sure.

Thanks

tatersinc, try cleaning the main ECM ground (look for a 3-wire brass connector) on the thermostat housing. The next time you have a long CEL, perform the K-Test--the voltage will likely be a fraction of a volt. I suspect you are experiencing intermittent ECM failure. I wouldn't bother with the confirming test--it's not worth the time.

Greasemonkey, I tried K test and got 4.95 volts. I am still going to try and switch out ECM. I stripped the ground nut (mine actually had 4 four wires to it instead of 3) so I have not taken it off to clean it. Could it just be an intermittent ground problem if not the ECM? But if that was the problem wouldn't the CEL not be on?

The only thing is I never had the problem with my other ECM. BTY, now my check engine light is not going off at all and I left it on for over an hour.

I ended up doing the confirming test too. Found schematics here:

.:FFS TechNet : OBD1 ECU Pin out Schematics :.

But I ended up getting 4.95 volts. Could there still be some other problem with ECM?

. Clean and fix the main ECM ground.
. Check all under-dash fuses with a test light or multimeter, particularly Fuse No. 24 and Fuse No. 12.

Greasemonkey,

I checked ground and fuses and they were fine. Any other advice?

Thanks

. Turn the ignition ON and, while the CEL is on, disconnect the Throttle Position Sensor (TPS). If the CEL goes out, the TPS is the culprit and should be replaced.

. Reconnect the TPS, turn the ignition On, and, while the CEL is on, disconnect the MAP Sensor. If the CEL goes out, the MAP Sensor is the culprit and should be replaced.

I unplugged those two sensors and others but the light stays on?

I have tried getting an error code using the paperclip method and I get a 92. But I don't think that is even a code for my year car.

Is the SRS light supposed to do the long and short blinks for the code? I have tried retrieving the code a few times over the last couple of months and the red SRS light does the blinking?

Code 92 = Evaporative Emission Control System insufficient purge flow

Don't know what else to suggest--however, don't give up!

Yah I saw that code too under generic codes on a website somewhere. But I called a Honda technician and he said for my year 1995 that was not a valid code. Anyway, that same code (if it really is one) was still going off when my car was working.

I am going to try a new ECM in a couple days and I will let you know what happens.

Thanks

I got a used ECM today and it fixed everything. Apparently it was bad. I will let you know if I have any other problems. Thanks for your help!

Update. Car is running fine since changing ECM.

I also found out the reason the SRS light was blinking is it has fault codes too. Both the SRS light and the CEL blink when you jump the diagnosis connector. I had taken my steering wheel off and that caused the SRS light to be on. I have since cleared it. Don't pay Honda $80-100 to re-set it. All you need is two paperclips.