[1941chevy]

The coil and icm check out OK. What is the check for the ecm ? Any other thoughts? Thanks, Bob

[TxGreaseMonkey]

Perform the K-Test on the ECM:

The K-Test: Remove the MAP Sensor connector and turn the ignition switch to ON (Position II). 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.


Bench testing coils and, particularly, ICMs is not reliable. I recommend replacing both of these problematic components every 120,000 miles or 10 years, whichever comes first.

If the CEL comes on and goes off normally, the problem is likely with the ICM and/or coil. Check all under hood and under dash fuses with a test light or multimeter.

[1941chevy]

Thanks TX greasemonkey for reply. I tried the k-test- no voltage. The cel stays on when I turn on the key. Also I plugged in an obdII reader and the reader won't even light up. Icm and coil have been replaced.

[TxGreaseMonkey]

. If the CEL does not go off when you turn the ignition switch to ON (Position II), the problem is with the ACG (ALT) (S) fuse, in the under dash fuse/relay box; ECM (perform the K-Test); main relay; or the ignition switch. Perform tests in that order.

. Test all under hood and under dash fuses with a test light or multimeter:

https://www.askmehelpdesk.com/cars-t...tml#post252145

Be very thorough, since this will save a lot of time and money.

. Check the ignition switch for wear, pitting, or melting:

https://www.askmehelpdesk.com/cars-t...tml#post224652

I just want you to check each of the areas above, before condeming the ECM. Ensure you performed the K-Test properly, turning the ignition switch to ON (Position II). Here's how to replace the ECM yourself:

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

Look for a remanufactured ECM (exact Honda part no. match) with a lifetime warranty. Based on the ECM completely failing the K-Test, it appears to be the likely problem.

[1941chevy]

Where is the main relay. Also could it be the crankshaft position sensor ? There is a ckp in the distributor. Is there also another behind the crank pulley? Thanks

[TxGreaseMonkey]

Your main relay could account for the CEL staying on, though it's not a high probability. The CKP is not the problem. All attention must be focused on determining why the CEL doesn't go out. If it doesn't the car won't spark. The problem resides with one of the four items I mentioned above.

Check AutoZone.com, to see what the main relay looks like. Then, my best guess is to look left of fuse box, wedged against left kick panel and above hood latch. Remove fuse box cover and lower dash panel for access. Also, turn the ignition switch on and off, in order to help you hear and feel it click.