SC Ignition Wire Impedance

[Johnb911]

My SC Motor is misfiring.
I just put it back in the car after the winter projects.

I refurbed the stainless shields of the wires and put thick shrink wrap over the spark end where the wire enters the plug holder
Had sparking to engine issues last year.

I measured the impedance from the distributor end right to where the spark plug touches

They all measures between .98 and .95 when the meter was set to 200K Ohms.

Can someone explain what this really means as the threads I have found say it should be higher.

[Johnb911]

Bump

[Walter_Middie]

Had sparking to engine issues last year.

John,

Sparking to engine issues will not be fixed by refurbing the stainless shields. Sounds like you need new wires. It is also possible you still don't have a good connection onto the spark plugs. This can be tricky to get right.

[Skitstoval]

+1 on the wires

[ossiblue]

From personal experience, save some time and frustration and invest in new wires. You will then have a base line on a solid ignition system that you will not have to worry about for a few years.

[safe]

The wires them self has almost no resistance at all, but the spark caps has a resistor that can fail. It's pretty much always the caps, not the wire, that fails.

[ossiblue]

Originally Posted by safe

The wires them self has almost no resistance at all, but the spark caps has a resistor that can fail. It's pretty much always the caps, not the wire, that fails.

+1
It's typically the connectors that fail, especially Beru which should have a resistance of 3Kohms but often will short out under heat or vibration.

[Gunter]

To be clear:
Stock SC ignition harness with braided steel has Beru connectors on both ends.
The cap-end has a short one with ~1k OHMS.
The plug-end has a long one with ~3k OHMS.
The wires have no resistance.
To test, check each wire with connectors in place with a DIGITAL, not Analog, multi-meter end-to-end to get ~4000 OHMS total.
Any different result requires the connectors to be checked individually; simple and easy.

Berus are alright if you check the resistance once a year.
I have new non-braided 8mm wires with Beru each end.

John, get new wires and if you need to replace some connectors, advertise for some used Berus on PP "For sale and wanted"
And try a lower test-setting than 200K.

[Johnb911]

Gunter

I am a little confused on the dist cap end I have the little rubber shield and then a smal copper unit with a nipple that is soldered to the wire exiting the cable.

When I did my testing I probed from the nipple to the metal piece inside the connector that snaps around the top of the spark plug.

Was this the correct method?
and
What would you suggest next if not?

Thanks

[Gunter]

Originally Posted by Johnb911

Gunter

I am a little confused on the dist cap end I have the little rubber shield and then a smal copper unit with a nipple that is soldered to the wire exiting the cable.

When I did my testing I probed from the nipple to the metal piece inside the connector that snaps around the top of the spark plug.

Was this the correct method?
and
What would you suggest next if not?

Thanks

Sounds like an after-market home-made harness.
Take one complete single wire off and post a picture so we can see the end-connectors and how the wires connect into them.
You may not have Beru and may not have any resistance in the connectors which is alright providing the wires are in good shape and the long plug connectors don't allow arcing (grounding) into the case.

[Johnb911]

Will do
thanks

[Johnb911]

Here are some picks from my phone.