Questions and Answers

Honda Civic Has A Weak Spark Q. I have a no start situation on a 1991 Honda Civic LX 5-speed and 144,000 miles. Pulled the car into the driveway with everything seeming normal. Then the car sat three weeks due to my travel. When I went to start it, it was in a mode where it just cranks and cranks. It doesn't fire on ether either. Fuel pressure is okay and plugs are getting wet with fuel.

I had the whole distributor checked out, and it made a huge blue spark for the shop, but to me, when installed, the spark looks weak.

I've been checking grounds, no problem found. All fuses to fuel, ECU seem to be okay. No codes stored in the ECU. Tach doesn't bounce when cranking. This is 30 miles into a refill of the tank, and I don't trust the crud out of the pumps here in Colorado this time of year. Still I don' think the fuel expires that quickly.

Timing belt is only about 20,000 miles old, but I took off the valve cover and couldn't see any potential problems like a loose belt, odd looking teeth or fraying. Why couldn't Honda have made it easier to line up the timing marks???

Three times, after I disconnected the battery for 30 minutes to reset the ECU. When reconnected it would fire once and went into crank, crank mode. I put another ECU in it this weekend, and still no go.

Any thoughts? In 9½ years of ownership, this is the first time for such antics. Any tricks to get it into a "limp home mode" to use for trouble shooting? I am reading a lot of postings about relays and no start problems, but those seem to be when hot. If I lived at the top of hill, I'd try starting it in "RUN" by popping the clutch to see if the problem was in the start circuit.

Thanks,
Neil and Susan

A. With this car, I would have to look at the main relay. This has always been the weak link in the chain. Read Honda Main Relays for information on how to test them.

Assuming the distributor and igniter are, indeed, good, you will need to check the coil. The fact that you do have some spark would tend to indicate the rest of the ignition system seems to be working.

To check the ignition coil, measure the resistance between the (+), black/yellow wire, terminal and the (-), white/blue wire, terminal of the coil. The resistance should be about 0.6 to 0.8 ohms at 70° F.

Then check the resistance between the (+), black/yellow wire, terminal and the coil wire terminal. It should be about 12,000 to 19,200 ohms at 70° F.

If the readings are out of specifications, replace the coil.