1994 Honda Civic EX, 1.6 liter

Cranks, but will not start. Solid CEL, no blinks.

- Jumping diagnostic connector makes no difference.
- Replaced igniter (genuine Honda $275!), distributor cap, distributor rotor, coil, and spark plugs.
- Main relay is good, removed and bench tested.
- Fuel pump is good, removed and bench tested.
- Fuel pump can receive voltage.
- New fuel filter.
- Passes K-test. 4.98 volts between MAP connector and ECU ground on thermostat.
- ECU ground on thermostat is clean.
- Ignition switch cleaned. All switch positions have continuity specified in the service manual.
- ACG fuse is good. ECU fuse is good.
- I can force it to start by spraying starting fluid into the intake. Runs fine then, but won’t restart.
- Unmounting and unplugging ECU, then reinstalling it used to make it run for a day, but the problem would return the next morning. Now that trick no longer works.

Please tell me what else could test. I’m at my rope’s end. This is my daughter’s car. I had to loan her my car to get to work. Now I’m afoot.

If the CEL does not go out, most Civics will not spark and the fuel pump will not run. Most of your attention should be focused on the ECM.

Ensure the ACG(ALT)(S) fuse contacts are clean and inserted in the proper slot. Remove and clean the ECM fuse, located in the under hood fuse box. Finally, remove the main ECM ground, clean the brass connector with abrasive cloth and coat with dielectric grease.

Remove your ECM, disconnecting the negative battery terminal first, and look at the likely heat discoloration on the metal covers. You will probably observe a spiral blue pattern. ECMs don't have fan motors to cool them and, to make matters worse, are often covered by carpeting. Heat, vibration, flooding, and shorts, among other things, reduce their lives. Look for heat crazed microprocessors in the ECM. The electrolytic capacitors in 1989-94 Civics are known for leaking.

If the problem persists, substitute a known good ECM, even though it passed the K-Test. It's amazing your ECM has lasted this long. Bottom Line: Your car likely suffers from intermittent ECM failure.

If the engine consistently starts with starting fluid, then my fears about the ECM may be unfounded. In that case, I would install your new igniter, coil, rotor, and distributor cap in a genuine Honda distributor housing (others are suspect). One or more internal distributor sensors (CKP, TDC, or CYL) may have failed.

This is an interesting case--please let us know the solution.

Thank you so much TxGreaseMonkey !

The fact that it will run with starting fluid, and removing/replacing the ECU would make it work for a while was weird to me also.

I replaced the distributor cap, distributor rotor, and coil, so your diagnosis of intermittent ECU failure sounds promising. I intend to take the ECU apart again and inspect it with a magnifying glass.

90% chance of rain today in my part of Texas. I will get back to you with some photographs of the ECU as soon as my driveway dries out.

Thank you for helping me!

Progress!

Per your recommendation I cleaned the ECM ground connection on the thermostat housing. The darn car started afterwards. It started again this morning. If it starts again tomorrow morning I will believe this was the problem.

ECM ground connection before cleaning:
http://flowthego.com/civic/ecuground1.jpg

ECM ground connection after cleaning:
http://flowthego.com/civic/ecuground2.jpg


I also noticed what *might* be heat-swelling on some IC chips in the ECM.

Whole ECM.
http://flowthego.com/civic/ecu1.jpg

Close-up of the suspect chips.
http://flowthego.com/civic/ecu2.jpg

I'm keeping my fingers crossed. I will report back soon.

Rats! I just checked again this afternoon. She won't start. Same symptoms.

I will order an ECM and report back.

Nice pictures. Yes, the microchips appear crazed by heat.

There is still a lot of corrosion on the main ECM ground, even after the cleaning. Use 260-grit abrasive cloth or steel wool to get it shiny. Also, clean the bolt (wire wheel) and thermostat housing. Afterwards, spray the parts with WD-40 and reassemble.

Still sounds like intermittent ECM failure, to me.

Did you solve the problem?

I'm still fighting this thing.

I purchased a defective ECM from Ebay seller autocomputerwholesaler. eBay My World - autocomputerwholesalers I'm currently in negotiations with them to refund my money.

Here is a one-minute video which compares the performance of my (sometimes) working ECM with the defective ECM they sent me...

http://youtu.be/LqEJKLYiLe4



I will keep you updated.

Here is a photo showing my original ECM versus the rusted, beat-up, defective ECM autocomputerwholesaler sent me for $150...

http://flowthego.com/acw/acwecm-sm3.jpg

The "new" ECM looks like it went through the Iraqi war.

Spray the A, B, and D harness connector with WD-40.

I finally resolved this issue. The car ran fine when I did not install the metal cover/kickplate over the ECU. My guess is that the metal cover was bending the connectors in some way.

After a month-long complaint process and many phone calls, I got Visa to reverse the charge for the defective ECU sent to me by autocomputerwholesalers.com I did not even have to mail back their piece of junk ECU. I threw it in the trash.

I sold the Civic a couple of weeks ago.

Thank you so much for your help in this matter!