Ongoing SC no start issue

[dntlft]

OK guys, I've now discovered my car lacks spark at the plug and at the coil wire. My car originally lost power when trying to drive home on 5 cylinders (big mistake) and the gas in the exhaust cooked my Cat. I figured simple replacement with a bypass pipe and new plugs would fix it. Nope. Where do I go from here, I don't want to continue throwing parts at it without really knowing whats going on...

[schumicat]

do a search for green wire (conntects to dizzy).

is the cd/ignition box whining.

[dntlft]

When you refer to dizzy, do you mean the distributor? I checked all fuses, and the CD box (~6 inch square metal box on drivers side of engine cptmnt?), it emits a very high pitched tone when ignition key is turned but not all the way to cause the starter to turn. Does that mean the CD is OK? It was rebuilt by the previous owner about 3 years ago

[dntlft]

With a Bosch unit at a cost of $900

[dntlft]

I did a search for green distributor wire, which took me to the 928 tech forum. Would I have to physically remove the distributor to change out the green wire? Also, it looks like this wire just sort of disappears into the wiring harness of my 911SC. How would I go about connecting the opposite end of this wire, crimp it on? I this wire COULD possibly be the culprit for my no start situation, because my catalytic converter/muffler were both extremely hot when my engine just sort of abruptly shut down. I thought it was my CAT matrix melting/clogging that caused the shutdown, but this no spark issue has me rethinking...

[timmy2]

The green wire is actually 2 wires, "a coax". There is one wire inside and a shield wire surrounding it.
It sounds like you have the later continuous wire version that costs a lot to buy...( there is a version made of 2 sections with a replaceable shorter green wire component)
There are different options to repair it if it has failed.
It is held in the distributor with a metal clip.
If you undo the dist and turn it you should be able to get to it.
Test continuity of the wire from the 6 pin connector to the 2 small slots on the plug removed from the distributor.
PM me if it has failed and I can help you fix it.

[dntlft]

Thx timmy2, actually I should probably rule out the ignition coil as a potential culprit first, but I'm not sure how to trouble shoot that. I DO own a multimeter. How may I determine the health of my coil?

[timmy2]

Measure the resistances of the coil and post your results.
Center to negative terminal,
Center to positive terminal,
Negative to Positive terminal,
Center to case.
Neg to case,
pos to case.

[timmy2]

bosch coil resistance

[dntlft]

Measured my Bosch coil resistance:
Center to negative 696 ohms
Center to positive 695 ohms
Neg to positive 0.8 ohms
Center to case 696 ohms
Neg to case 0.4 ohms
Pos to case 0.8 ohms

[timmy2]

Sounds like it is in spec.

[dntlft]

If in spec, what to do next?

[dntlft]

I tested this coil with it still in the car, should I remove the coil and do a bench test?

[SC-targa]

Hopefully the CDI is still good.

Check / replace the green wire.

[dntlft]

When I turn the ignition key to on position, but not far enough to turn the starter, I can hear a high pitched tone from CD box, plus I have service records from the previous owner showing that the Bosch CD box was replaced along with the bosch coil about 2 years ago. The green distributor wire appears to be very old (original?)

[timmy2]

As posted above, continue to test each component of the ignition and confirm it works as it should.
Green wire as discussed earlier is next in your list of suspects.

[timmy2]

If the engine harness is original, the green wire probably is too as the newer models have the single continuous wire without a connector to replace just the "cooked" part of the wire.
Test it and go from there.

[dntlft]

How would I go about testing this green wire? Find the 2 ends of this wire and test for resistance with multimeter? Is there some other way to test it?

[emac]

#1 900.00 for a rebuilt Cdi !!
#2 I had same issues high pitch sound from Cdi it WAS bad
Many on this board repair for about 300.00 or MSD
Just my 2c
Ernie 81sc

[timmy2]

In post 6 I told you how to check it. Here's more detail:

You may have to insert a paper clip or similar in each hole of the end that comes out of the distributor as it is very small, just to get a meter probe on it. then unplug your CDI pin connector and 2 of the 6 female connectors correspond with the 2 wires in the green wire coax. Check them for continuity, and check to see they aren't shorted to each other.

If you pull back the rubber boot you will see a white or green wire that is the center wire of the coax, and a black wire that is the shield wire covered in black tubing.