THE SPOOKY TOPAZ

A friend of mine truly believes that some cars get possessed. He says that the
evil spirits from previous owners, or from mechanics that have passed on - but
had worked on the car sometime in the past - come and take residence in these
haunted vehicles. Not being a believer in ghosts, I found this theory hard to
believe. But I must admit, there seems to be some truth in his rationale. At
least when it came to a certain Topaz that seemed to be possessed.

When he came across a car that defied logic and just flat-out refused to be
fixed, he performed his own version of an exorcism. Oh no, he doesn't burn
candles, practice Voodoo, consult a Ouiji board - or anything like that. He
says the best way to exonerate a possessed vehicle is to provide a path for
the spirits to return to the earth. He reasons that the spirits are trapped
because they can't see a path to ground, because the tires are insulators.

His method involves providing a path, or shunt, to ground. He calls it "Bushing"
the car. Really, it's quite simple. He drives the car over to a special place in
the back of his shop, a place that he's designated specially for this purpose.
In that place are some bushes. That's right, bushes. And he drives the car right
smack dab into the middle of these bushes, where they can rub up against the
sides of the car. And then he leaves it there for a couple of days.

And that's supposed to cleanse the car of bad spirits and "ground it out" back
to the earth. Car bushing. Drive it over into the bushes and leave it. Pretty
wild, huh? Well. I've not had much need to "Bush" a car, not until I met the
brown Mercury Topaz that drove into my shop. And I should have known right off
when the owner said that he was afraid his car was possessed. Looking back, I
should have known better. I should've refused to work on it right then and
there. But, my guard was down and I accepted the challenge. Big mistake.

The car had a sordid history before it showed up at my place. It had already
been to three Ford dealerships, and five other shops. The long list of repairs
that were listed and the items that were replaced really shocked me. The
computer had been replaced twice. Also replaced were the TBI Injector, coil,
distributor & distributor module, TPS, MAP, 02, fuel pump & relay. Because Fords
are bad on wiring, additional grounds and power feed wires had already been
checked - all to no avail. This one was going to be tough. Really tough.

The worst thing about a problem like this is that it doesn't always happen. I
always say "Intermittence is the bane of auto repair." And this one really acted
as if it were possessed. It would act up at any time and place, day or night,
hot or cold. Suddenly, without warning, that 2.3 liter engine would lose power.
As you were driving along at a steady speed, or during light acceleration, the
Topaz would just dog out. The power dropped off, just like the catalytic
converter was somehow plugging itself up, or the fuel was being restricted.

I once had a VW that would act this way, and it turned out to be a chunk of
catalytic converter honeycomb that had come loose, and was rolling around inside
the catalytic converter. From time to time, it would wedge itself against the
outlet in the converter, causing a massive power loss similar to this. But, that
problem showed up on a vacuum gauge, and it wasn't that difficult to track down.

This one, however, acted like the computer was being possessed. Maybe it had
dual personalities. I don't know. Maybe some old mechanic was getting revenge on
the owner for some unknown reason. I could tell it was the computer because my
friend Bob told me. You see, the first thing I did was to get out Bob and
connect him to the car. Bob stands for "Break-Out-Box." This is a special tool
that provides a way of interfacing between the computer and the rest of the car.
You simply unplug the computer, plug one of the Bob harness connectors into the
computer and the other into the car's wiring harness. It's like a huge telephone
tap.

I quickly discovered that when the evil spirit took possession of the car, the
mixture would go really lean. But what didn't make sense was that the computer
was reducing the amount of fuel being sprayed by the injectors whenever this
happened. Normally, the injector is held open for 4-6 milliseconds. But when it
went awry, the pulse went to 3 and stayed there - no matter what else happened.
You could stand on the throttle and it would stay there right there at 3.

Okay, you're probably thinking the computer must have been bad. So, did I say it
had already been replaced twice? Did I say that there were no computer fault
codes? Well, I even tried swapping it out with the computer from another car
just like it. And it didn't make a bit of difference. I called up one of my good
customers and invited him to come over and have lunch with me. And while we were
at lunch, my lead tech swapped the computers. When we got back, he had a scowl
on his face - signifying that the computer swap made no difference. Back to the
drawing board.

Next, I tried adding some fuel myself. I connected a propane bottle to a long
hose and ran it into the throttle body. When the engine started losing power, I
simply turned on the propane and guess what? All the power returned. Just so
long as I added propane, it would have full power. Well, that made sense. But
what if I were to artificially trigger the fuel injector? Same thing. All the
power came right back.

Well, you've got to know that there are other kinds of wacky things that will
make a vehicle seemed to be possessed. One of them is the alternator. It can
appear to be charging just fine, but be producing some invisible alternating
current right along with the direct current that it's supposed to produce. The
simple way of telling is to unplug it. Been there, done that, no help.

Next, I decided to check the grounds and power feed wires, just to be sure the
previous tech did the job right. Again, no help. Getting a bit desperate, I
decided to systematically disconnect the EGR, the EGR control solenoids, the
cooling fan, the inside blower motor, and a bunch of other stuff. I mean I was
getting into a real panic. Why did the computer keep commanding the mixture to
stay lean? Why would it go to a fixed injector pulse, instead of following the
normal routine of making the pulse longer as the engine saw a load, or the
throttle was mashed?

Maybe the injector was faulty. I don't care that it's already been replaced.
Damn that! I've seen plenty of replacement parts that were just as bad as a
junkyard dog. And this may just be that, I figured. Maybe that injector was
stressing the computer somehow, which was going into a limp-home mode because
it was too stressed. So, I ordered another one, and low and behold, it made
absolutely no difference. Fiddle sticks.

At this point, I was beginning to believe in ghosts and looking around for some
bushes to drive the Topaz into. I mean, I was desperate. How could a car defy
logic? It was then that the thought occurred to me that I might be able to borrow
my good customer's Tempo for a day. I would offer him a free tune up, oil change,
and car wash if he let me use his car for diagnostic purposes. And I would tell
him that I would be forever grateful to him if he helped me solve this puzzle.
I'd even buy him dinner.

To make a long story short, swapping parts did find the problem. In fact, it was
the first thing that I swapped that made the problem go away. Bless the Lord for
that! I decided to swap the throttle body first because I knew that there were
several potential gremlins that are part of it. But, to my surprise, it wasn't
any of the buggers that I thought it might be. I know, because after swapping the
throttle body made the problem disappear, I swapped out each individual item
that comes as part of the throttle body - that I thought could cause the problem
- and not a one of them helped.

First, I changed the throttle position sensor. Then, in that order, I changed
the hidden inlet fuel filter, the fuel pressure regulator, the fuel injector, and
finally the throttle body itself. Oh, there's one thing that I need to tell you.
Bolted onto the outside of the throttle body is an idle speed control motor. Up
until I swapped out the throttle body itself, I hadn't paid it much attention.
Why should I? I mean, this wasn't a stalling problem. We're talking about a
running problem here! What in tarnation can an idle speed control motor cause to
make a car lose power, I ask?

Well, don't be made a fool like I was made by that blasted idle speed control
motor. It was the culprit all along! You see, it's supposed to not only control
the idle, but it has a built-in switch that also tells the computer when the
throttle is no longer being pressed. It is called, in the vernacular, an "Idle
Tracking Switch." That's right, this switch, called "ITS" not only motors
against the idle lever to make a perfect idle speed, but it also spies on your
foot - to be able to tell the computer just when you start to press the gas
pedal.

Now, you can sympathize with me for not checking it, right? The ITS is supposed
to be twelve volts anytime you aren't touching the throttle, but is supposed to
go to 0 volts the moment you start to press the gas. Well, guess what? This
damn thing was measuring twelve with no gas, but had three or four volts when it
was supposed to have none. And, for some reason, the computer was getting
confused and going into some kind of fail-safe mode. But, you would think that
the computer would know that the ITS was bad, right? After all, it has the input
from the throttle position sensor, too? Well, think again. The stupid computer
didn't have a clue that the ITS was bad. It's garbage in and garbage out.

Looking back at the whole ordeal, I guess that car computers are pretty stupid
after all. I mean, I used to think how great they were, being able to identify
malfunctions, turning on the check engine light and story trouble fault codes.
And being able to operate at the speed of light. Now, I have a different view of
them. They have the intelligence of a palmetto bug, and are as stupid as the day
is long. And as far as human smarts against computers, at least we learn from
our mistakes, over and over again, until some kind-hearted human being takes
pity on them and comes along to help it out. And that's just what I did. No
bushing around either, and that's a fact.


TITLE: THE SPOOKY TOPAZ
From Nutz & Boltz August 1999 Volume XI Issue #: 8 Page 11

automotivebible/mechanics_nightmares/Mechanic'sNightmares.htm