On Thu, Jul 7, 2011 at 11:10 PM, TerribleTom <silvereightynine@aol.com> wrote:
>
> Ok so I'm changing plugs and wires on the GM product in my garage (89
> Caprice, 305, TBI) when I thought to do something I had not done with a
> tune up before... ohm the plug wires.
>
> Trouble is I'm not really sure if the results are good or bad or neither.
>
> Took two wires for the same plug (same length) and tested them. Multimeter
> set on 20K Ohm's -- old wire came in at 12.5 and the new wire was 10.5
>
> That level of difference seemed uniform across the set. Shorter length wire
> had less resistance - as I guessed it would, being shorter... less cable to
> travel through... old wire was 9.5 new wire was 7.5
>
>
> Nice to see the old wires had higher resistance... as that makes me feel
> that much better for replacing them... regardless of the fact that the
> rubber boots felt mealy, and were discolored. The 1/2 inch or so portion of
> the wires that protruded out from the distributor end of the plug wire boots
> were also a yelowish tint on the grey wires. Further leading me to believe
> it was time to change them. Didn't help that I ripped the terminals off a
> wire or two trying to get them off the plugs.
>
> Anyway.. back to the ohms. 20K setting would mean that the resistance of
> that first wire I tested was 12,500 omhs - and the new wire was 10,500 omhs
> - correct? Is a 2000 ohm difference in resistance a big deal?
Seems a little high to me, although if you're not using resistor plugs
its likely on the money. BMW specs about 5k per secondary wire and 1k
for the coil wire for my car, but it requires resistor plugs so IIRC
it ends up right in the 10k range for the total circuit. (Bosch W8LCR
plugs in case anyone was wondering)
I would think that the tolerance would be less than 2k ohms, so odds
are it's a big deal. Either way, you're replacing them so I wouldn't
worry about it.
-- - Josh
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