I was working on a 1997 Sebring JX, which is a convertible in case you don't
know Chrysler terminology. Anyway, I was looking for a noise that the owner said
was driving her crazy. Now, it's not unusual for me to try to check out a "noise
complaint." But this one turned out to be one of the most interesting ones that
I've come across. And when I finally did figure it out, it reminded me of some
of the wacky things I've run across in my many years turning wrenches.
Anyway, the owner says the noise is coming from somewhere in the dash-console
area. And it doesn't seem to matter if the car is running or not. The noise is
supposed to be there all the time. Sure enough, I hear the noise. This is an
important distinction. Quite often I just can't. Sure, it might be there, but I
just don't hear it. Maybe my ears are just too old or maybe I'm just not
familiar with the cacophony of sounds that the car normally emits, and the new
addition is just drowned in the background.
But this noise is distinct. It is a clear beep. And if you were to time it, like
with a stop watch, which is what I did, you'd discover that it beeps exactly
every 2 minutes. On the dot. And like most noises, it's damn hard to locate. It
seems to be coming from everywhere. Kinda' like a pager going off in a crowded
room and everyone looking down at the same time. And being a convertible made
matters even worse, because the noise was less confined than it would be if
there was a top on the car.
I have this cool tool that is essentially a pair of headphones connected to a
microphone. You can use it to hear teeny weenie sounds that are impossible
to locate. Just stick the microphone where you think the sound is coming from
and give it a listen. It hears valve tap, piston knock, and water pump bearing
noises really well. It also hears air leaks and hard to track down squeaks and
rattles. And you can turn up the volume and even hear your own heart beat!
So I grab the tool and find the beeper lodged between the passenger seat and the
console. The lady owner lost it a week before, and was absolutely grateful when
I showed it to her. Now how do you charge for a job like that? Anyway, it
reminded me of other strange jobs I've had. Like the 1991 Buick Regal that came
in with the red battery warning light glowing. Open the hood and there's a
brand-spanking new battery and alternator. Whoops. Something really wrong here.
Somebody's spent a bundle and isn't very happy.
It turned out to be a real hair-puller too. Turn the key on and start it, and
that light is there staring you right in the face. So I decided to do a little
detective work and pull the alternator connector, which should turn off the
light. Right? Wrong. This means there's something wrong in the wiring. Big time!
Further investigation with a razor into the wiring harness reveals a mass of the
harness wires melted all together. A real mess. But oh no! It just doesn't end
there. Not a chance.
I spend a whole day splicing and repairing the wiring harness only to find that
this doesn't fix the problem, which was a dead short. Further detective work
found aluminum foil wrapped around the courtesy light fuse. But that was not
all. No, it doesn't end there. Nope. The reason the fuse is wrapped with
aluminum foil was because of a dead short in one of the accessories, mainly the
cigarette lighter. And the kicker is that someone (maybe the same boyfriend that
was kind enough to wrap the aluminum foil around the fuse for her), has put a
brand-new shiny penny in the cigarette lighter socket.
Which reminds me of another weird alternator electrical one on a 1989 Cadillac
Deville, which was towed in with a no start complaint. After running the
standard charging and starter draw tests, it looks like the alternator is bad.
No biggie. Wham-bam thank-you-ma'am and it's done. Right? Wrong again, Charlie!
Two days later, it's back in my face along with the customer who's this
hot-headed 22-year-old military dude swearing that I'm a rip-off and he's gonna'
call the police. I say wait just a sec while I check this out, and lo and behold
I see that the battery cable ends are toast. Funny, I didn't remember them that
way before. How could I have missed it? So I slap on a couple of those
do-it-yourselfer battery cable ends and send him on his way.
Well, the Cadillac is back in my face a week later, hanging from the back of a
wrecker. And Mr. Military Macho-man is madder than ever. Well, this calls for
some further investigative work and I tell him to call a cab and I'll let him
know tomorrow what's the problem with his Deville. Now, mind you, this ain't no
ordinary Deville. The suspension has been chopped, the wheels are "stylin"
California super-chromed with tires the thickness of rubber-bands. The windows
are all blackened-out and the floor in front of the back seat is covered with
huge speakers. And there are more speakers mounted on the back deck and woofers
under each of the seats.
And this time, when I go to turn the key on, I'm greeted with an audio
bombardment of gansta-rap that is loud enough to loosen my fillings and give me
a concussion! It scared me right out of my wits, and I couldn't move fast enough
to turn the damn thing off. Which of the 57 buttons is OFF? You know, the kind
of lyrics-that-spew-expletives-every-two-words kinda' rap-music. Did I say
rap-music? Now that's a real oxymoron.
Oh yes, did I forget to tell you? There's a hole where the factory radio used to
be and stuffed in it and hanging half-out of the hole is a huge stereo. And in
the trunk, next to the pair of 27" speakers is a huge amplifier. Gingerly, I
grabbed hold of the stereo and pulled it out of the dash. There was a huge gang
of wires going to it, and the factory harness was severely butchered. The first
thing I noticed was that the orange wire with a black stripe that goes to the
Body Control Module was cut and spliced, and that the dash stereo was tapped
into it using common household electrical wire nuts.
While wire nuts are fine and good inside an electrical outlet box in the wall of
your house, wire nuts are not meant to be used in automotive wiring. Why? They
aren't shake proof. And I cringe any time I see wire nuts on a car or truck. I
can't tell you how exasperating it was to see literally dozens of them in the
wiring that was hiding behind the radio. I still shudder when I think about it.
More detective work reveals that the A/C fuse is missing, which just happens to
be on the same circuit as the alternator. Okay.
With the fuse happily back in place, the alternator begins charging again. But,
why was it removed? Did it blow? Further investigation and charging tests reveal
that when the stereo is cranked up, which I'm sure this brain-dead soldier must
do when he's cruising, causes the system to draw more than 80 amps. Now, this
alternator is only rated for 75 amps. You do the math and you'll understand why
the alternator fuse blew when I cranked it up (with ear protection this time).
The key to unraveling the mystery in the Gansta-Deville was knowing that we as
mechanics are having to deal with a whole new breed of customer. To solve the
riddle, it was necessary to crank up the stereo so that it became obvious that
the charging system couldn't handle that kind of drain. That lesson I had
learned the hard way, literally from the school of "Hard Knocks". It involved a
1994 Chevy Caprice that came to me with a low power complaint.
The reason this Caprice comes to mind is because it also involved one of those
high-powered stereo systems. But, I hadn't been to the school of "Knocks" and
didn't know that the stereo played a part in solving the riddle. Anyway, owner
had some other shop install a junkyard engine in the Caprice, and that's when he
said the problem began. But, this was one of those kinds of problems that only
happens for the customer. You know, it just wouldn't run right for him, but
purred like a kitten for me.
Finally, after trying and trying to do what I call "Put a wrench on his word
problem," I decided to make him show me exactly what he was talking about. So,
we jump in the Chevy and off we go for a spin. And we're not very far down the
road when he reaches over and turns on the stereo. Then, he proceeds to crank it
up to ear-shattering levels. Well, there I sit with my fingers sticking in my
ears while he is driving and sure enough, the engine starts to falter, surge and
buck.
"Whoa! What's happening here?" I shouted. He says, "Wait a minute," and proceeds
to turn down the stereo. And the moment he did, the problem vanished. "That's
why I couldn't find your problem. It's connected to your blasted rap music!" I
said. I never ran the stereo, nor would I think to run the stereo while checking
out his problem. In fact, I never touch anyone's radio while working on their
cars.
Oh sure, I've seen plenty of techs blasting their customer's radios as they
service their cars. And from time to time they get caught, as the customer gets
into the car, only to turn on the ignition and be greeted with a huge blast of
their stereo. And of course, it's always playing the kind of music they hate
most. And even worse, the volume is left turned to full blast. Now imagine a
little old lady who only listens to classical music, getting into her car and
being greeted by gangster rap at 130 decibels! Not a pretty picture.
And those car radio presets are an even worse problem. You know, the programming
feature that lets you set the stations to the ones you like to listen to. The
radio loses its presets when you disconnect the battery to service the
terminals, right? But even worse, probably Murphy's seventeenth-law or some
such, it will automatically program itself to those stations that play the kind
of music the owner of the car hates most. If the owner likes country, it will
reset to classical. If he likes classical, it will reset to rap, and so on.
And when the customer returns and gets in his car to drive away, he is convinced
that the mechanic purposely reset all the stations to the kind of music the
mechanic likes. As if we mechanics have the time in the day to sit around and
reprogram our customer's radios! Right! But, thanks to Murphy and his laws, it
sure does get us in trouble, or at least leaves us with some explaining to do.
And to make matters worse, the late model radios will just plain lock up and
refuse to work if you disconnect power from them. And boy, howdy-do, you take a
customer's music away and they'll really get hopping mad in a big hurry. In
those cases, you have to contact the dealership and get the unlock code to make
the radio work again. Talk about a hassle!
Anyway, as I was saying before I drifted away into radio land, this Chevy would
only run bad when the radio was cranked up. Talk about an odd problem! "Now what
can playing a radio loud possibly have to do with how a car runs?" you may be
asking. I sure was.
The very next thing I did was to monitor the computer with my diagnostic
scanner. Why? Because I had a hunch that the noise the speakers were making were
somehow rattling a circuit in the engine control computer, which is pretty much
in the vicinity of the right-hand radio speaker. I figured that this would show
up somehow on the data stream from the computer
Well, I was right and wrong. While the computer didn't show any problems with
the data stream when I cranked up the stereo, the engine knock detection system
did. In fact, when the stereo peaked with its "bump-and-thump" chest-pounding
rhythm, the engine timing retarded in perfect cadence. It was as if the engine
knock sensor was keeping time with the stereo!
Not believing that an engine knock sensor could be so sensitive as to be affected
by the stereo, I decided to do a little detective work. I would try another
knock sensor. That's called "test by substitution," and that's when the fun
really began. When I went to the side of the engine block to unscrew the old one
and replace it with a new one, it was gone. There wasn't any place for it to
screw it into the engine block, and the wiring harness that should lead to it
was clipped!
How could I be seeing a knock signal, if the sensor is missing and the harness
has been cut?" I asked myself. Well, to make a long detective story short, it
turned out that there was still a knock sensor, and it was still connected to
the computer. You see, in order for the General Motors engine timing control
system to operate correctly, the knock sensor must be present and accounted for.
If you disconnect it, the engine control computer will immediately miss it,
throw off the timing and turn on the "Check Engine" light.
So when the engine block had been swapped out with another one, the used block
didn't have anywhere to mount the knock sensor. The previous mechanic had
clipped off the wire, thinking that he could simply eliminate this little sensor
and no one would be the wiser. But then, when he started the engine and the
check engine light came on, he realized that he wasn't going to get away with
it. So what do you think he did? Well, I'll tell you. He traced the knock sensor
wire back to the computer, spliced in another wire, and added the knock sensor
back into the circuit right there at the computer. And when he was done, he
tucked the knock sensor out of sight, right behind the speaker! And that's why
the Chevy ran so bad every time the stereo was cranked up. The knock sensor
thought the engine was pinging and the computer responded by retarding the
timing!
Anyway, as I said when I started, this business of being a mechanic has
certainly turned into a challenge. You never know what kind of strange and
unusual problem is going to roll into the door next. I remember the time a fat
rat got into a Fiat timing belt and ruined the engine. Ah, but that's another
story.
