Jumpy Tachometer Revisited

Hello,

I posted a message not too long ago about my 1990 Civic's tachometer
being really jumpy. A few people responded and said it is probably the
ignitor. (ignition module) However, after doing a bit of thinking, and
talking to a certified Honda mechanic, I would like a third opinion. The
Honda mechanic mentioned that it could be the coil going bad. Since the
tach gets its "reading" from the coil, and the engine IS NOT "missing", that
makes me want to rule out the ignitor and believe that it is the coil. BTW,
as I mentioned in my first post, before I replaced the distributor cap and
rotor button, the first cap was only held on by ONE screw, and the contacts
were rusted inside. Of course, rust means moisture, and moisture + an
electronic coil = bad news. So, in lieu of this new information, would
y'all be willing to agree with me and say it's the coil going bad? My only
other thought is that it could be a sensor going bad, but how likely is
that? I know my car has an Engine Speed sensor, but if I unplug that, I
can't even go over 2,000RPM because the speed sensor controls the timing, so
that's not the case. Does the 1990 Civic have a such thing as a "Throttle
Position Sensor"?

Thanks again, everyone!

Jonathan

 

I had the same problem, it was the pickup coil in the distributor. It
was $20 and took about 15 minutes to install with basic hand tools and a
feeler gauge.

HTH

Carl

 

OOPS! Forgot to mention this was in a 1984 Toyota Celica GT-S with the
fuel injected 22RE.

Carl

 

Well, you win a few, you lose a few...I replaced the coil in my car...NOT
the problem. I mean, the coil did need replacing, but it wasn't causing the
tach to jump. So I am learning the hard way to go with my "gut" and not
think things through too much. At first I was sure it was the ignitor, but
thinking about it too much made me think it was the coil. I appreciate all
of the info from everyone...I have a new ignitor on order now...hopefully my
problem will be solved as soon as I replace it. BTW, my car has been
running progressively worse. It "misses", hesitates, and almost backfires
now...*sigh*

Jonathan

 

I have a 92 Honda Civic. The electrical diagram from the tech manual shows
the tachometer output coming directly from the ignitor to the ECU. The
exact same thing happened to me. Jumpy tach and then eventually car died
completley with no spark. Make sure you mark position of three bolts that
attach distributer to motor if you decide to take the distributer out.
Also note the position of the rotor and put it back in the same position
when reinstalling so that you're not out of phase. The socket I used was
a 12 metric. If you have cruise control it will probably be either not
working or failing as well since it relies on the tachometer output from
the ignitor as well.

Good luck.
Redrum