On Thu, 31 Jan 2013 18:16:56 -0800, Erik wrote:


And from 1996 on up, diagnostics is a lot less of a "black art".

Not so! Especially with some mfg's.

Here's an excellent example:

http://www.youtube.com/watch?v=3-MTko-otio&feature=em

Yes, I know it's long... runs just over 40 minutes... make some popcorn
& kick back.

We see stuff like this more often than you'd think... scan tools really
have to be taken with a grain of salt. You really have to be careful, or
you can end up eating very expensive parts, and/or blowing more time
than you could ever bill for.

This is why I say buy 'real' car's & trucks.

Erik

PS, Incidentally, this 'ScannerDanner' guy has many superb automotive
computer related troubleshooting video's up on YouTube.
Like I said - the scanner does not tell you what to replace. It tells
you what is wrong.
It says the right bank is lean, or the left bank is rich, or the left
bank front O2 sensor is slow, or reading low.. It is up to the
mechanic to KNOW what will cause those problems. And how to find /
eliminate the possibilities without throwing the parts department at
it. Do you have a bad injector? or a vacuum leak? Or is the engine
burning oil?

Or the scanner tells you you have an intermittent misfire. Or a
misfire on cyl 5. What is causing the misfire? A bad plug, a bad wire,
a bad coil, a vacuum leak, a bad injector, a bad valve? At least you
know to look at #5 cyl, not 1, 2, 3, 4, or 6 (or 7 or 8)
It is the combination of codes and/or other symptoms, together with
the history of the vehicle, and knowing what goes wrong on certain
vehicles.

You did not have that ability on the older cars - Yes, you could hook
a scope to it - and if you knew how to read both the primary and
secondary patterns, the vacuum guage, the dynamic compression test,
etc it COULD give you most of the information. But not everyone had
the money and space to have an analyzer scope. Every DIY shadetree
mechanic can afford a basic OBD2 scanner, and it will fit in the glove
compartment (or even the ash tray)

The mid-year stuff - electronic controls but pre 1996 (pre OBD2) every
vehicle needed it's own specific scan tester - some gave lots of good
information, and others were almost useless. Some would blink the CEL
when you connected the right combination of pins/wires on the test
plug to spell out the code.