The auto newsgroups need a FAQ like the sci.electronics.repair FAQ.
I've seen so many so amateur mechanics who are so clueless about
troubleshooting procedure that it isn't funny. For example, I once
had a room-mate who's car had died and he was walking to/from work for
a week. He had a friend over who was in the process of ripping the
dash apart and I asked him what he'd checked so far. He was starting
at the ignition switch. I joked that he should check if there was air
in the tires, and fuck me drunk, he was about to follow my advice.
I took over and started right at the ignition system. Pulled a wire,
had him crank the engine and there was a nice fat spark. Next: fuel
system. Asked if there was gas in the car. They didn't know, the
fuel guage was broken. I pulled the gas cap and rocked the car and
didn't hear any splashing. The car had run out of gas right at the
moment it was parked and couldn't start again.
People need to learn some trouble shooting skills before they start
asking questions like "my car won't start; what part should I replace?"
I've been guilty of the same thing. I had an acura integra that
wouldn't start. No spark. Checked the coil and it measured good.
Replaced the ignitor. Still no spark. Was about to replace the
output transister of the ECU, but was so impressed with its internal
aerospace quality, that I decided to keep looking elsewhere. Put the
ECU->ignitor signal on an osciloscope and saw a pulse. Replaced the
coil that had measured good. Fixed the problem and only wasted $90
which was more than a mechanic would have charged to diagnose and
repair it in the first place.
the ones that piss me off are the ones that /try/ to fix things, foul
something up, frequently unrelated to the first, /then/ want it fixed
while all the time insisting that they didn't touch anything.
moral of the story: don't trust a single word people tell you on
diagnostics - always do it yourself.
any [honda] manual relying on a simple resistance test of a coil is
wasting a whole bunch of peoples time and money. modern potted coils
frequently pass the resistance test ok, but flash over internally and
are consequently useless. the only reliable test is to manually trigger
the igniter unit and see if the coil sparks a test plug.
I never thought of that. I think I was afraid of frying the ignitor
with a too long pulse or too high a voltage pulse as would be the case
if you touched it with a wire to 12V. Also, I didn't mention it
earlier, but the ECU threw no codes. The output was clearly open loop.
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