Intermittent spark on '79 Rabbit

Well, back to the old rabbit. I need to replace the timing belt on my 83 rabbit, so I need to get the 79 Rabbit up and running. Anyway, I was using the Bentley manual to diagnose the problem (no spark in the high tension wire from terminal 4 as measured by timing gun) , and I think I found it. The voltage between terminal 1 and terminal 15 is only 7 volts, and according to the manual, it should be 9.6V or higher. It then goes on to say that the problem may be "poor distributor point contact [unlikely -- they're new and the reading didn't change when I pressed the points together manually], a shorted condenser [maybe, but it's also new, although I DID have the coil from my 83 rabbit installed briefly ...] high resistance in the ignition switch or the wires that connect the switch to the coil. " Unfortunately, it doesn't say how to test these last two items. It DOES give a spec for the resistance wire -- 0.85-0.95 ohms. I do have a meter that could read that, but that seems like it would be hard to get an accurate reading that low anyways. I did the same voltage test with the wires disconnected from the coil and got a reading of 12V. BUT the red wire which attaches to terminal 15 on the coil didn't give me a reading. That is, when I hooked the green wire that goes to terminal 1 to the red wire that goes to 15 (through the meter of course), I got no reading, even with the ignition switch turned on. Could this be the problem? The starter solenoid is putting out 12V, so I'm gessing that's not the problem. Any ideas? And thanks again for all the help you guys gave me with my other rabbit!!!!!

Reply to
Fred Mann
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The coil is different in the 83 car.

points coil resistance between 15 and 1 1.7 to 2.1 ohms

1 to 4 7,000 to 12,000 ohms

You read terminal 15 with the ground being ground. That big connection on the battery marked -. Or the metal that holds the coil, or that braided wire that attaches to the hood, or bare aluminum on the head. Terminal 1 is the points which may or may not be closed.

You test high resistence with an accurate multimeter.

You could go to the auto parts store and ask for a ballast resistor for a 1970 Chevrolet Nova. Attach one end to 15. Attach other end to positive on battery. Try to start car. You just eliminated the posible bad wiring from ignition switch to fusebox through resistor wire.

I had a coil wire go bad where it plugs in to terminal 4. I replaced coil and wire using correct coil.

Reply to
Jim Behning

Like Jim said the ign coil from the '83 is for the electronic ign and not the same. The voltage will be lower going to the + side of the coil with just the ign on. It is designed that way to prolong the life of the ign points. While it is cranking that voltage should go up to 12 volts AFAIK. It should get the 12V burst from the starter circuit like the cold start valve does. I could be wrong though. although I DID have the coil from my 83 rabbit installed briefly ...] high

Reply to
dave AKA vwdoc1

You win, Dave!! It was the condenser. The ground was weak. When I jammed a screwdriver between the condenser and the distributor, the engine perked right up. Very exciting!! So I just cleaned off the distributor with the wire brush attachment on my Dremel and screwed the condenser back in real tight. That did it. When's your birthday?

Reply to
Fred Mann

Reply to
Jim Behning

Hey Fred, I like the simple and "free" fixes! lol Help another out and spread the knowledge!

Reply to
dave AKA vwdoc1

Thanks again Jim and Dave. Strange that this little tidbit isn't in the Bentley manual. Well now it's on the interweb. Unfortunately, I'll be back soon. Fred

Reply to
Fred Mann

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