In the never ending effort to fix the "Herky-Jerky" problems with the
'95 Park Ave
the dealer reported the coil resistances "out of spec." "Will that
fix the problem I ask?"
He says "Not sure, but until we replace those bad coils we won't be
able to further diagnose
the problem." So, I told them to do it and save the coils for me.
Since I am writing this
note you probably can guess that it didn't fix the problem.
I looked up the specs on AllData and did my own measurements. I get
around 0.4 Ohms on the
primaries and around 5600 Ohms on the secondary. AllData says it
should be 0.5-0.8
on the primaries and 5000-8000 on the secondary.
While the primaries are out of spec I'm wondering if replacement
really was indicated.
For one thing, it's tough to accurately measure resistance in the
range of the primary. I have two
digital multimeters and one measures 0 ohms as 0.3 and the other as
0.6. Naturally, I subtract
the 0 value from my measurements, but would not bet on the result
being accurate to anything
better than +/-0.2 Ohms. I also doubt that the tech had anything
better to measure with. I
would imagine one would need a decade box and a Wheatstone bridge to
get a reliable
measurement in this range. And, all 3 packs are very close to the same
value. My guess
is I'd get the same measurement on the new ones. I'm a little
reluctant to test them since
they have to removed for the primary measurement, and the dealer might
tell me that
would void the warranty on their work.
So, should I go back and argue with them? Should they put my old coils
back on and resume the diagnosis
I paid them $88 for, in addition to the $108 labor they charged to
replace the coils?
For newcomers wanting full background look for prior "herky-Jerky"
post. Basically, it's an
intermittent miss in the engine or something that seems to get
amplified by driving the torque
converter clutch control nuts.