Ignition woes

Dan must have finally gone to using drugs. DO NOT permanently add the auxiliary wire he seems to be suggesting, do so ONLY for testing.


Here's the above, simplified:

There are THREE separate circuits in the ignition switch to do with starting and running the engine

1 "start" traditionally yellow, "fires" the start relay when the key is twisted to start, AND on auto cars, when the start relay "sees a ground" in park or neutral. On newer "stick" cars with a clutch safety switch, the clutch must be down.

THIS YELLOW makes the starter "go."

2 "ignition run" , traditionally blue, also called "IGN 1" is hot ONLY with key in "run" and NOT in start. This feeds power to the "key" side of the ballast, and the regulator, one 70/ newer cars, feeds also one of the field terminals (blue) on the alternator, electric choke if used, and sometimes a couple of other things

IT IS IMPORTANT to understand that at least on many models, this goes "cold" during "start."

3 "bypass" traditionally brown, also called "IGN 2" comes directly from the ign switch, is hot ONLY in start, and goes to the coil side of the ballast resistor. It provides "hot" voltage to start the car.

DO NOT permanently run an auxiliary wire from the solenoid, the relay, or any other place to "replace" the brown bypass EXCEPT possibly for TESTING, something which the benevolent, all the time "Dan" failed to mention.

This is BECAUSE when the solenoid is not engaged, the voltage fed to the coil will "backfeed" to the solenoid, causing the coil voltage to SAG

So to sum up IT IS PERMISSIBLE to run an auxiliary wire from the coil + to a battery source DURING STARTING and FOR TESTING. Remove this wire when the engine runs.


There are about 3 ways to fix this problem.

1 Do some "unpleasant surgery?????" as Dan wants to avoid

2 Install a different start relay like this, used on later Jeeps, which DOES have an auxiliary contact in the relay:

http://oljeep.com/gw/elec/StarterRelay.jpg

You'll notice this relay looks very similar to what is on your car, except for the added "BAL" terminal, which you connect to the coil+

3 You can also connect to the small square exposed terminal on the present relay (not the big stud) OR the "yellow" push on terminal and run a DIODE in series from there to the coil + connection. Diodes have a BAND on one end which identifies the cathode, and you want the band to go towards coil connection.

To properly troubleshoot this, do the following:

Hook one probe of your meter to battery positive, and hook the other to the "key" side of the ballast resistor, or the regulator "I" terminal, or if you have a 70/ later alternator setup, to the blue field wire.

Turn the key to "run" with engine off. You are directly measuring voltage drop from the battery, through the harness, to the ignition supply buss, and you "want" to see a VERY low reading. More than .2--.3 volts (three TENTHS of a volt) means that you have some drop in the harness, and you should look into it. Your top suspects are poor connections in the bulkhead connector, at the ignition switch connector, a bad switch, or in the ammeter circuit in rare cases.

THE ABOVE affects the "run" condition.

TO TEST the "bypass" circuit, which is probably your trouble, disable the ignition by pulling the coil wire out of the distributor, and grounding it.

Hook one probe of your meter to battery positive, and the other to the coil positive terminal. Crank the engine USING THE KEY and NOT by jumpering the start relay. AGAIN you want to see a VERY low voltage, on the order of not more than a few tenths of a volt.

To double check this, hook your meter to ground at one probe, and to the coil + with the other probe, and repeat. THIS time, you should read "same as battery" voltage when cranking the engine WITH THE KEY