"Been expecting you, George," called
Stan Hicks, as a well-cared-for '58 Cadillac, its left-front fender
crumpled, pulled up at the Model Garage.
A tall, sad-faced young man eased out
of the driver's seat, nodded morosely to Stan, and then just stood there
gazing at the damaged sheet metal.
"Don't worry," Stan said cheerfully.
"My boss will prove you were in the right. Let's go talk to him."
Gus Wilson sat in the office, perched
on his favorite swivel chair, relaxedly puffing his pipe.
"Gus," Stan began, "this sad-looking
guy is George Fox. He's an old buddy of mine, and he's got a problem."
Gus smiled a welcome, then asked,
"Aren't you the parking-lot attendant at Sam Eastman's restaurant?"
"Ex-attendant is probably more
accurate," Fox answered glumly, "unless you can explain why that Caddy out
there stalled all of a sudden last Sunday."
"Okay," Gus said. "Let's start at the
beginning,"
"That Caddy belongs to Eastman, Mr.
Wilson," said Fox. "It's his pride and joy, and he keeps it in great shape.
Last Sunday afternoon, while I was putting it into his reserved parking
space, the engine quit - just like that - and so did the power steering. I
lost control for only a second, but that was enough to plow into a lamp post
next to me."
Gus followed the young men outside,
and made a quick examination of the car's battered front end.
"Does Sam Eastman blame you solely for
the accident?" Gus asked.
"Yes and no," said Fox. "At first he
believed my story that the car stalled. But then his mechanic checked it
over. He got the report yesterday: The engine is in perfect mechanical
condition. So now he thinks I lied about the stalling to cover up some kind
of dumb driving.
Unless I can prove otherwise by five
o'clock - that's when I promised to return the car - I'm out of a job. And I
guess I'm out of school, too."
"School?"
"Uh-huh. I'm taking a
computer-programming course at the State Technical Institute. That's why the
parking lot job is important to me. I can go to school in the morning and
work in the afternoon."
"Fair enough," said Gus. "Let's do a
little detective work." Gus glanced at Stan. "I suppose we can assume that
Sam's mechanic made a thorough check?"
"Yup," agreed Stan. "And just to make
sure, I went over the engine myself. Ignition and fuel systems are okay.
So's the carburetor. And the transmission seems right. The exhaust system
has no blockages."
"Okay, Stan," said Gus. "The next step
is a test drive, and on the way back, a return to the scene of the crime."
The big engine roared to life
instantly, and quickly idled down to a silky-smooth purr. Gus piloted the
Caddy onto Main Street for a bit of stop-and-go driving in town, followed by
a short turnpike hop at high speed and a medium-speed tour through suburban
streets. The engine performed flawlessly.
They were a half-mile away from Sam
Eastman's restaurant when Gus pulled up. "You take over, George," he said.
"Take a long route to the restaurant and make as many turns as you can."
Sam Eastman greeted them as George
steered into the restaurant's driveway: "Afternoon, Wilson . . . George . .
. have you uncovered something my mechanic missed?"
"Could be," answered Gus. "Where
exactly did the accident take place?"
"Follow the driveway to the end and
make a wide right turn," said Eastman.
"Want me to drive on up there?" asked
George.
"Nope," said Gus. "Let's head back to
the garage." He called out the window to Eastman: "Why don't you come with
us? You might find it interesting."
"This some kind of hocus-pocus,
Wilson? You know my car runs like a Swiss watch. Now, why doesn't George
just back down from his silly story and admit he made a careless mistake.
I might let him stay on the job."
George looked at Gus, and shook his
head.
"Sam," Gus said, "I believe that this
car did stall on Sunday."
"That's ridiculous!" said Eastman.
"No, it isn't ridiculous, but to prove
it I'll need some gear that's back at the garage. Want to watch?"
Eastman grunted, but opened the rear
door and slid onto the seat. "Wilson," he said, "my mechanic assures me that
there is nothing wrong with the engine that could make the car stall the way
George describes."
"Your mechanic is right," said Gus,
"on that. The trouble isn't anywhere near the engine."
On the apron at the Model Garage, Gus
left the Caddy's engine running, got out and headed for the workshop. He
returned with two small hydraulic jacks and placed them under the car's
front and rear bumpers to lift the right side.
"What's that for?" growled Eastman.
"To stimulate the effect of a right
turn on the car," answered Gus. "During our test drive I noticed that the
engine missed slightly every time we took a right turn. It sounded just as
if we were running out of gas. I suspect the trouble is in the fuel line -
but we'll soon see.
George, you start pumping the rear
jack. Match your strokes with mine so the car lifts uniformly on the right
side."
The heavy car body began to rise
slowly, stretching the springs.
"What we're doing now," Gus went on,
"is shifting the car's weight to the left side - that's exactly what happens
during a right turn, because of centrifugal force."
The Caddy's right side was tilted up
about four inches when the engine began missing; then it coughed and died.
"Well, I'll be - " said Eastman. "Why
did it do that?"
Gus was too busy examining the ground
just beneath the car's left-rear rocker panel to answer. In a few moments he
found what he was looking for a tiny puddle of gasoline being fed by a
steady drip from under the car.
A loud series of horn toots startled
Gus, as a small school bus wheeled past the gas pumps and screeched to a
halt. The excited driver jumped out and flung open the hood.
"Drop everything, Gus," he shouted.
"This is an emergency."
"Hold on, Al," Gus answered, "I'm
right in the middle of . . ."
"No time - no time," the driver
interrupted, "I've got to pick up 10 kids at Hiawatha Day Camp in exactly 20
minutes."
Gus looked back at George Fox and Sam
Eastman. Both nodded.
"It's gremlins!" the driver rattled
on. "I step on the brakes - the parking lights and tail lights come on with
the brake lights. I flip on the left turn signals, they work for a second or
two - then they lock up, and my parking and tail lights come on, too! I'll
show you." He slid into the seat and stepped on the brake pedal.
"Nothing seems wrong," said Gus. "Only
your brake lights are lit up now."
"That can't . . . " the driver began,
but he didn't finish. The tail lights and front parking lights had blinked
on.
"Could be an intermittent short in the
wiring," said Gus.
"A short circuit wouldn't account for
the time delay, Mr. Wilson," said a voice behind Gus. It was George Fox.
"I'd say it's some kind of switching action that connects the two circuits."
He turned toward the driver. "You say
the turn signals are also involved?"
The bus driver flipped the lever to
the left. The left signals flashed twice, then stayed lit at low brightness
level as the taillights and parking lights came on dimly.
"You seem to know a lot about
automobile wiring, George," Eastman remarked, winking at Gus.
"Not really. But computers are built
of thousands of switch-type circuits, and I'm wondering if one of the simple
design techniques I've been studying won't pinpoint the trouble."
"Point ahead," said Gus. "Need any
test equipment?"
"Nope, just a pencil and paper,"
George answered. "I want to make a logic diagram describing the various
circuit faults we've seen."
He drew a three-by-three-box square
grid on a piece of paper. "The idea is simple. I'm going to make a table
that compares the lighting effects we're getting with what we want to get.
I'll write 'okay' if the correct lights come on; 'fault,' if there's error."
George studied the table, then turned
to Gus. "The common denominator of the circuit trouble seems to be the
left-rear signal lamp. Am I right in assuming that this one lamp serves the
left stop light and left-rear turn signal?"
As Gus nodded, George continued.
"Then somehow the lamp must be making
electrical contact with the parking-light/tail-light circuit."
"The dual-filament bulb!" Gus
exclaimed. Quickly, he unscrewed the lens of the left-rear lamp.
"Hit the brakes again, Al," he called
out.
Gus watched as the bright signal
filament lighted normally. But then the hot filament sagged slightly and
touched the medium-power tail-light filament. Instantly, the tail lights and
parking lights came on.
"Here's your short circuit, Al," he
said. "It's inside the bulb itself."
"What about the turn-signal problem?"
"When the left turn signal is on," Gus
answered, "this sagging filament flashes normally until it heats up. When it
short-circuits against the tail-light filament, the other lights come on,
and the greatly increased current locks up the flasher, so everything stays
on at reduced brightness. Cure - a new bulb."
While Stan replaced the playful lamp
on the bus, Gus led George and Eastman back to the jacked-up Cadillac. It
took Gus only a moment to feel along the Caddy's gas line, on its left side,
until he reached the source of the dripping gasoline - a section of line
directly under one of the clamps that held the line to the frame.
"Here it is," he said, "a tiny hole in
the steel gas line. It's corroded."
"But why haven't I noticed any
symptoms?" asked Eastman.
"Because," said Gus, "the hole is
usually blocked by the clamp. When you make a right turn, though, the weight
transfer distorts the frame slightly, and the clamp lifts away from the
line.
This lets air into the line and breaks
the fuel-pump suction. On a normal right turn, this causes a slight miss; it
stops as soon as the clamp reseals the hold, when you straighten the car
out.
"But," he continued, "on a wide right
turn - the kind George made when he parked the car - the engine actually
runs out of gas and stalls."
"I guess I owe you an apology,
George," said Eastman.
George grinned. "How much do I owe
you, Mr. Wilson?"
"Not a thing," said Gus. "I'll let Mr.
Eastman pay for repairing the gas line. And as far as the diagnosis is
concerned, your bit of sleuthing earlier should even us up."
"I get it," said George. "One good
turn makes up for a bad one."
END
