On Thu, 26 Feb 2009 14:17:28 -0500, "Steve W."
wrote:
Half-Nutz wrote:
On Feb 25, 10:17 pm, "Robert Swinney" wrote:
"Bruce L. Bergman" wrote

Silly question number one: Is it throwing a computer code and
lighting the Check Engine Light? And if so, what are the codes?

If it's enough to worry about, the OBD-II computer will notice it.

Only at idle, worse when cold... You might be right about a dirty
injector. Try some Chevron Techron additive in the tank first.

If that doesn't work, buy or borrow a fuel-rail connected injector
cleaning kit and a can of the cleaning solvent. The kit costs about
what you'd pay to have it done once, and if you are careful to buy a
decent one it will be good for many years.

What you want to do, is read out the code.
That vintage, they have temporary codes, that they save, for a while.
You can read out the code with nothing more than a jumper wire, it
will flash the codes out on the dashboard light.

For example, code 23 is two blinks, delay, three blinks, long delay,
repeat...

if it was a 94 he could use a jumper wire. An 04 on the other hand
cannot use a jumper to pull the codes.

The "short the T and E1 terminals and watch the blinkenlight" method
only works on OBD-I systems from the eighties and nineties. When they
switched to OBD-II fully computerized, that function went away.

A problem that it notices, then goes away, it still saves, for a
while. If the problem is solid, the light stays on. if it gets better,
it goes out, but remembbers the code(s).
I had very good luck, it told me exactly What was wrong.. Changing
that.. Fixed it. Neat system.

Exactly - you need a scanner handy and watch the data as the misfire
is happening, because the temporary codes go away after one or two
restarts. It may be picking up the fault and setting a temporary
code, but below the severity threshhold where the ECU sets a permanent
code and turns on the Check Engine Light.

You can get a decent OBD-II scanner for between $60 and $100 if all
you need is to keep the engine running right.

You can also spend $5,000 of you need a professional grade scanner
with every bell and whistle, including reading airbag systems, ABS
systems, transmission ECU's and other esoteric crap. But if thge
repairs are beyond your skill level you probably don't want to drop
that much coin on the fancy reader.

Lets hope for the next generation OBD-III they really follow the
mantra "On Board Diagnostics" and they use a "glass dashboard".

You plug in a keyboard and a mouse, the dashboard switches to
Diagnostic Mode and acts like a terminal. If they have a dozen CPUs
running the car, it should be trivial to program a rudimentary user
interface to access all the data going back and forth.

Would be invaluable for those of us that drive way off the beaten
path, and/or get stuck out in severe weather. Could make all the
difference between driving 20 miles out to civilization, or hiking
out. And if it's way below zero or above 120, you might not make it.

-- Bruce --