THE ELUSIVE “JUICE”
It takes good “juice” and lots of it to run a modern auto; not the kind
that Uncle Sam has put a ban upon, for that ran the auto into the ditch
oftener than most anything else; but something quite as hot and with at
least an equal amount of “kick” in it—the electric “juice.”
Probably this is the least understood element in running a car, if one
may judge by the troubles reported. Large numbers of autoists have no
idea of the functions of the batteries and wires and switches and other
parts of the electrical equipment, and when anything goes wrong they
are helpless.
In dealing with the electrical equipment of a machine the owner should
understand that a complete circuit is necessary in order to have the
current do its work; that is, starting with the battery as the source,
a wire leads the current from the battery through the switch to the
device to be operated, and then the current must be led back to the
battery before it will do any work. It is not sufficient simply to lead
the current to the device; if there is no way back to the battery it
will not get even as far as the switch. It won’t travel except on a
round-trip ticket.
In looking for trouble electrically the first thing to inspect is
the battery. See that it is charged—has current in it. That can be
determined by using a voltmeter (for dry cells an ammeter) or a
hydrometer. Then each successive terminal from the battery should
be tested. For instance, there is a wire to the lighting switch. It
is insulated and the first place to test after making sure that the
battery is O. K. is at the switch. If there is no current there the
wire may be broken or the terminal connections poor; but whatever the
trouble may be, you have narrowed it down to one small stretch of wire.
The next step would be to test where the wire leaves the switch to
go to the device to be operated. If the current gets to the switch
and does not get out of it, it is apparent that the trouble is in the
switch, or if it gets to the switch but not through the fuse, the fuse
is at fault.
If the current leaves the fuse and does not get to the lamp which
the switch controls, then we know that the trouble is in that wire
somewhere; if it gets to the lamp but the lamp will not light, we know
it is in the lamp; if we can trace it through the lamp, but it does
not reach the battery, we know that it is the wire leading back to the
battery which is at fault.
If the current is carried back through the frame of the car, as is very
often the case, frequently the ground connections are poor or there is
a break in the ground. Thus, we might attach a ground wire to a piece
of iron on the dash, and if this is of wood that piece of iron might
be insulated from the remainder of the metal work of the car and the
ground connection would not be complete.
Recently the author came across some electrical troubles which were
rather mysterious to the owners of the cars, but proved to be simple
under systematic search. One man worked all of one Sunday morning,
with the help of several sympathetic owner friends trying to find out
where an extra wire on his switch should be connected. He could not get
the engine started, the horn would not blow, the headlights would not
light, the starting motor would not turn over, but the dash and tail
lights, which were in series, did light.
A little experiment developed the fact that when the starting pedal was
depressed the dash light grew very dim. This, of course, indicated
that it was not possible to draw a very large amount of current from
the battery, or that the battery was either in a discharged condition,
or that the connections leading from it were poor. It was found that
when the wire connected to the battery terminal was moved, the light
would brighten up. This wire was disconnected and cleaned carefully
to make sure that the contact was good. When it was assembled again
no improvement was shown, so it was taken apart again and a careful
inspection showed that one end of the taper on the inside of the
terminal had a slight shoulder, which prevented the taper end of the
wire from being drawn into place snugly. Therefore a very light contact
was made and sufficient current could not pass to operate the starting
motor. This shoulder was removed with a penknife and the engine started
without difficulty. Several hours’ time would have been saved if the
owner had started to look for the trouble at the source of the current
instead of puzzling over the end of a wire that was not intended to be
connected to anything and had nothing to do with the trouble. It was
simply an extra wire for use if some new device should be installed.
A week later this same man was unable to start his engine and again
worked over it several hours before calling for help. This time the
lights were all right, but the engine would not start. To determine
the condition of the battery, he turned on a light and depressed the
starter pedal as before, to see if the light would dim very much under
the heavy load; as it did not, it was decided that the battery was all
right this time.
The hood was open and it was observed that when the starter pedal was
depressed the fan did not revolve and therefore the engine was not
being turned over, though one could hear the starting motor buzzing
plainly. This showed that the overrunning clutch of the starting motor
was slipping. As correcting this trouble was a shop job, they cranked
the engine over by hand, but still it did not start.
To make sure that a spark was being delivered, the wire leading from
the ignition coil to the high tension distributor was disconnected and
given about 1/16 inch gap. As soon as this was done it was plain to see
that a spark was being delivered, and the engine started immediately
also. Making a slight gap in the secondary circuit increases the
intensity of the spark at the plug and often aids in starting a balky
motor. This was an occasion when an outside spark gap was of value.
After the engine was warmed up, it was started several times without
difficulty.
Another fellow who was in trouble had a “sick” horn. It sounded like
a man who has a cold clogging his vocal organs—that is, it gave a
cracking or rattling sound instead of a musical note, if the sound of
a horn can be called musical. This type of horn has a notched wheel
which revolves and strikes against an iron pin riveted into a disc.
The disc in this way is made to vibrate, giving the desired sound. An
examination showed that the pin had become loose and rattled. It was
explained to the owner what the trouble was and he was told that the
pin was of hardened steel and as it was rather difficult to rivet it,
it might loosen up again. He replied that he would not worry about
that, because now that he knew what the trouble was he could easily get
it fixed again or replace it if necessary.
Another fellow had a horn which would not play because it had become
grounded and blown the fuse. The ground was removed, but as no fuse
could be obtained, a single strand of very fine wire from an ignition
cable was substituted in place of the fuse. This wire was small enough
to burn up before other short circuits could do damage to battery or
wiring.
Still another fellow had his car laid up for a week while he tried to
find out what was the matter with it. He had sent magneto and coil to
the factory for repairs and when they were returned to him a new type
of coil was provided. He wired it up the best he knew how, but the
engine would not start. Checking the wires over very carefully, they
seemed to be placed properly, but a spark could not be obtained. Going
to the source of the current, a test of the dry cells with an ammeter
showed that they were dead. The fellow had lost a week’s use of the car
because, having decided that the trouble was at the magneto or coil, he
did not look anywhere else. He should have started at the battery to
trace the current.
Another case which came under notice was where one of the headlights
failed to light. A test showed that the current came to the lamp. To
make sure the lamp was not at fault the one from the opposite side was
substituted, but it would not light. The lamp was grounded by an extra
length of wire and it worked all right. Then it was found that the
ground wire, which was located back of the reflector inside the lamp,
had become loose.
Most of these troubles point to the fact that a complete circuit is
necessary to have an electrical current do its work. Therefore, when
trouble occurs, the source of the current should be examined first and
then the current should be traced through its entire path leading from
and returning to the battery.
It might be a good idea for the owner on winter evenings to get out
the wiring diagram of his car and trace the current from the battery
through each light, through the ignition system, through the horn, and
through every other electrical device used on the car, including the
generator and starting motor.
Also it might be good practice for the owner to carry his wiring
diagram with him when touring, so that the garage man, if there be
trouble, may be helped to quickly locate it. But if the winter evenings
be spent wisely in studying the electrical equipment, or even the
entire car, or perhaps invested in a course of instruction at a good
school, the owner might be independent of the garage man for the most
part and besides have the satisfaction of knowing that when anything
does go wrong he can find it and in most cases fix the trouble. The
release from worry ought to be worth the time spent in learning how.