Startup of 28 tudor - HELP!

[CHerdic]

After 15 years of rebuilding, car is scheduled for a start up. When I made the final hookup of a new battery, to all new wiring, a big spark resulted.

Is equiped with a shutoff switch next to starter motor, positive grounded.

Where do I start to located problem?

[BRENT in 10-uh-C]

Start by disconnecting the power feed wire on the starter switch to isolate all of the power feeding the harness. Now reconnect the battery and see if it sparks. If so, you have a starter switch issue.

If not, then reconnect the power feed wire on the starter switch. Now remove the wire from the generator cut-out and see if you have a spark at the battery cable. Next disconnect/remove the light switch at the bottom of the steering column to see if your short is there. Just work by process elimination through the entire system until you find the issue.

[larrys40]

I would start by unloading the light circuit by removing it from the generator cutout or alternater connection if so equipped. It sounds like you have a short somewhere.... make sure your batter connections, battery hold downs, cables, starter connections... are all correct and nothing shorted to ground. I would guess you don't have a volt/ohm meter or are familiar with it's..... If you have a repro terminal box I would wiggle the studs and see if they are loose... or were warm from connection as the repros are a threaded screw from the back and come with a potential short issue new out of the box. To fix would require removal from the firewall, tighten the screw studs at the back ( terminal connections) and put some epoxy on the back side of the screwheads to fill the gap between there and firewall... this is insurance so it won't back out and cause a future short.

If there is not short with just the engine harness and instrument panel harness you have an issue in the light circuit harness/light switch.... my guess is it is elsewhere..
Of course ifyou have a volt/ohm meter you will find your short quickly.... Double check your instrument panel connections as well.


I had a house call I made yesterday to one of our local members and he said he replaced the ammeter but then it kept blowing the fuse afterwards. I pulled the instrument panel and he had removed the thin nuts on the repro ammeter and placed the electrical connections up against the case with insulators and nuts on top.. thus creating a dead short condition... the ammeter will never be the same!
Common sense... being alert as to your connections, soldering electrical, tinning wires, using heatshrink are all good electrical procedures to use.

Keep us posted on the root cause.
thx.
Larry Shepard

[H. L. Chauvin]

Hi CHerdic,

It really is a very simple matter once you just sit down & think.

For example:

1. Why guess ??????? Electrical current "flow" through a particular wire cannot be "seen".

2. However. a very simple, inexpensive multi-meter can indicate & detect in volts, (say 6 volts), whether or not there is current "flow" in a particular wire.

3. Also, this simple little multi-meter can be dialed to Ohms in order to check the "continuity" of electrical current "flow" in a particular wire to insure a particular wire is not broken inside the insulation or armored cable, or even disconnected along the electrical "flow" route.

4. Electrical current in wires "flows" with absolutely no interruption, just like water "flow" in a pipe from the battery's negative (-) post to (+) ground.

5. FWIW: Appears multi-meters are similar to one's favorite credit card -- don't leave home without it -- and it always comes in handy & avoids embarrassment when both you & your car are broke.

[Tom Wesenberg]

A heavy duty flasher and an inductive ammeter are two handy things to have to find shorts. connect the flasher between the battery post and cable. The short will make it flash and if you also connect a headlamp bulbe in series with the flasher you will save the flasher from overload. Then move the inductive ammeter along the wires and each time the flasher sends current the ammeter will flicker. Once you move past the short the ammeter will no longer flicker. I've also used a compass to do the same thing.

The Model A is pretty simple in it's wiring and has a few usual repro parts that cause problems, so by the time you run to the store to buy a flasher and inductive ammeter, you will probably have found the problem.

[CHerdic]

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Problem appears to have been caused by wires from a new wiring harness, not yet attached to headlights shorting out on the floor. All were caped off , problem gone.

The start up process continued. Starter motor worked as expected, turns engine; 5 seconds later, at least one plug fires. Second attempt; engine starts and runs for 15 to 20 seconds then stops.

This rookie has had lots of experience wiring and houses and electrical panels. No sparks or fires and the work always passed inspection. The multi meter purchased last year is still a mystery to me. My next attempt to make the car run will happen when a Model A friend in on hand.

The good news, no leaks from the radiator, 5 quarts of oil are still ready to go (no leaks) and the no alcohol gas is waiting for the right spark.

Also plan to become a student on how to use my multi-meter.

[700rpm]

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