a4 coil wiring

A4 turned itself off. Looking around, found that one of the wires coming from the coil is not connected at it's other end. It is about 6" long and black. I think it is the (-). What should it connect to?

Looking at the wiring diagram, there is a wire shown from the coil (-) to the side of the distributor (upper left of diagram). What does that mean? Is it a ground?

Thanks
--Steve

sounds like the wire from the points (in the distributor) to the coil came off. Usually it's a spade type connector and you should be able to just slip it back on. I'm thinking you have a female connector on the wire that came off and you'll find the male end it plugs on to just below the distributor cap on the side of the distributor - the part on the distributor side goes through the body of the distributor to the points on the inside, but you shouldn't have to worry about that at this point. The points opening and closing control the firing of the coil.

A-4 coil wire

If I remember correctly the wire from the coil to the distributor ran directly with no breaks. A ring terminal or spade connector at the coil end and a ring connector at the points end. The wire ran through a small notch in the bottom rim of the distributor cap.

after looking at everything very carefully, turns out the dangling wire is connecting to the POS coil terminal - even though it is black. The IGN (purple) and alternator (red) also come from that terminal so that's how I know it's POS. The + and - markings on the coil are corroded away.

The NEG wire (black) from the coil to the distributor seems to be ok (and there is a wire which I think goes to the tach which seems to be ok).

I can't see anything this would go to. Conjecture that it is some sort of old wire that never went anywhere. Which means engine quit and won't start for some other reason.

So it's a call to the mechanic afterall.

--Steve

Posibilities

If the engine stopped suddenly then the problem is more than likely electrical. Using a glove, pull the coil lead barely out of the distributor and have some one turn the engine over. You should see a very energetic spark between the lead and distributor. If you don't then the coil is suspect. If you get a strong spark there then try the same routine with a spark plug lead. If you don't get a strong spark then the points are suspect.

another spark test that is sometimes easier/less likely to bite you is to pull a plug, leave the wire connected, and lay the plug so the metal hex part the wrench goes around is on a grounded surface, like a clean bolt (no paint) on top of the valve cover. Crank the engine and you should see the plug spark.

These engines typically have the ignition wired via an oil pressure switch. Bypass the switch to make sure that's not the culprit. Usually when something like this just stops, it's something simple. It doesn't take much for these little guys to run - one of the beauties of the great little A4.

steven said:

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I can't see anything this would go to.

--Steve

Click to expand...

just for grins, have you swung the wire around to see what it could reach?

Also, have you pulled the cap and looked inside? There's a little button in the center of the cap that pushes on the rotor. The rotor button has a spring behind it and sometimes they can fail. You should be able to pull the button out with your fingers inspect and push it back in. The button can also wear or fracture, but it's not very common. Put a test light in line with the wire that goes from the coil to the side of (points) the distributor, and the light should go on and off as you crank indicating the points are opening and closing. The spring on the points can break too, and they'll just stay open.

This is the kind of A4 repair I think you'll be much happier about if you solve yourself rather than wait around for a mechanic to show up and tell you to convert to a diesel.

There is a thin black wire that runs inside the distributor, and I recall it is susceptible to chafe, but I haven't had to deal with mine in five or six years since converting to electronic ignition...but if you can post a photo to the forums at moyermarine.com you'll get a very authoritative answer very quickly.