No Spark

[dbltrbl]

How many ohms between rotor center and rotor side pole (dont know what its called).

[Speedy Squirrel]

A Bosch rotor will have a 5000 Ohm resistor between the center contact and the side pole. The world is full of off-brand replacement rotors though, and these cars are old. It is possible that an aftermarket rotor with no resistor has found its way onto the car. They have only a few Ohms of resistance.

Originally Posted by dbltrbl

How many ohms between rotor center and rotor side pole (dont know what its called).

[SBK930]

Originally Posted by Speedy Squirrel

A Bosch rotor will have a 5000 Ohm resistor between the center contact and the side pole. The world is full of off-brand replacement rotors though, and these cars are old. It is possible that an aftermarket rotor with no resistor has found its way onto the car. They have only a few Ohms of resistance.

Just measured from the top centre to the tip and have 1.2 ohms.

It has had this rotor for as long as I can remember.

Steve.

[voitureltd]

I had a no start problem with a 77 930 and went thru everything mentioned in this post, like replacing the green wire, changing the CDI box with a spare i had , the rotor, cap, coil. All that stuff was original from 77 so some of it needed updating anyway. It turned out to be the ignition delay shut off, if that is what it is called. It keeps the ignition on a few seconds after you turn the key off which stops the fuel pumps but keeps the ignition on to clean the plugs. Mine just stayed in the shut off mode last time.. Found a NOS one and that cured the problem.

[flightlead404]

Originally Posted by voitureltd

I had a no start problem with a 77 930 and went thru everything mentioned in this post, like replacing the green wire, changing the CDI box with a spare i had , the rotor, cap, coil. All that stuff was original from 77 so some of it needed updating anyway. It turned out to be the ignition delay shut off, if that is what it is called. It keeps the ignition on a few seconds after you turn the key off which stops the fuel pumps but keeps the ignition on to clean the plugs. Mine just stayed in the shut off mode last time.. Found a NOS one and that cured the problem.

Delayed cut off relay. Its a small metal relay with a nonstandard base on the rear relay panel in the engine compartment. If you have two metal relays the larger one is the relay for a 2stage rear window defroster the smaller one is the delayed action relay.

[Speedy Squirrel]

I think the OP stated that the CDI box was buzzing with key on, and stopped buzzing a short time after key off, so I think the ignition delaying relay is working, if I understood correctly.

[SBK930]

Originally Posted by Speedy Squirrel

I think the OP stated that the CDI box was buzzing with key on, and stopped buzzing a short time after key off, so I think the ignition delaying relay is working, if I understood correctly.

That’s correct Speedy Squirrel.

But I am getting confused as Rawknees mentioned the high pitch noise from the CDI and I thought he meant that it was bad yet I read that, that meant it was good.

Also that the rotor could be bad yet it has a complete circuit showing 1.2ohms.
I am not sure if the OP meant that, that was not good.

[Speedy Squirrel]

Buzzing sound is a good sign from CDI box. Low resistance is good for a rotor.

[SBK930]

Originally Posted by Speedy Squirrel

Buzzing sound is a good sign from CDI box. Low resistance is good for a rotor.

I have not checked any fuses as yet so that will have to be next.

It is just getting very frustrating.

[pkabush]

Originally Posted by H/O Driver

Steve,
Even though the green wire looks good, since your at this stage anyway, I recommend you check resistance between the two terminals on that wire. My wire looked OK, well for the most part, but it ended up having an internal short (it's a coax wire).
Good luck,
Bob

Id look into it.

[SBK930]

Originally Posted by pkabush

Id look into it.

Hi pkabush,

Already done that by pulling the dizzy.

Checked out OK.

Steve.

[H/O Driver]

To clarify, and maybe you already did this, but you should also check resistance between the two terminals of the green wire when tested from the same end of the wire. As mentioned, there are two wires (coax) inside that green insulation that can't be touching each other.

[SBK930]

Originally Posted by H/O Driver

To clarify, and maybe you already did this, but you should also check resistance between the two terminals of the green wire when tested from the same end of the wire. As mentioned, there are two wires (coax) inside that green insulation that can't be touching each other.

H/O Driver,

Both wires checked out OK.

Thanks Steve.

[SBK930]

Here is the update.

Had Saturday afternoon to spend some time trying to figure out what the firetruck is going on.

Restored the wires to the coil and the wire that earths to the coil bracket.
Then had the better half kick it over while I had pulled a lead and stuck an old plug in and to my surprise there was spark.......not strong but there was spark.
Turned it off and there was a noise I had never heard before that sounded a lot like hissing air. As if a compressed air line had a leak.
We both had our heads in and around the engine trying to get a grasp as to where this noise was coming from. Well fruck me, I hit the CDI and it stopped.
Pulled no 5 plug, tested it and had a strong spark.
So reinstalled the plug, lead and IC, gave it a try and no start, but again that leaking air sound. Gave the CDI a crack and again it stopped.
Turned the key and my 930 came to life.
Best thing I’ve heard in a couple of months.

So the conclusion is my CDI is screwed. Don’t know if this will help anyone else trying to diagnose a no spark issue but try giving your CDI a kick in the nutz.
Because I took mine to an auto electrician and he said what the fruck is that, can’t test that and what is it. LOL!

Oh country livin.

Steve 930.

[pkabush]

Nice work. Way to stick with it.
You probably already know this, but any six pin CDI unit will work. It’s not a 930 specific part.
They come up fairly often here on the f/s board. Even better would be to send yours out for a rebuild

[Rawknees'Turbo]

SexySteve, what 70'sBush said ^^^, and if you are willing to ship your CDI to the USA, I highly recommend Bob Ashlock for testing/rebuilding/restoration of it - very reasonable cost, quick service, and all the communication you would want. Mine came back looking and functioning like new. He posts sometimes in 911 Tech, so you can probably find his contact info there, but if interested, I can send you his email in a PM.

[SBK930]

Thanks guys,

Came across this article which relocates a new CDI to under the seat.

Not sure which way to go yet. But thought this was an interesting alternative.

https://www.pcv.com.au/PorscheClubs/pc_victoria/pc_main.nsf/web/D2F466BC399FC1E2C125761F00277A68

Steve.

[Bucketlist]

Originally Posted by SBK930

Thanks guys,

Came across this article which relocates a new CDI to under the seat.

Not sure which way to go yet. But thought this was an interesting alternative.

https://www.pcv.com.au/PorscheClubs/pc_victoria/pc_main.nsf/web/D2F466BC399FC1E2C125761F00277A68

Steve.

Just for fun here are mine peeking out from under the drivers' seat.

[Speedy Squirrel]

Here for everyone is Bob Ashlocks business contact. He has done more than just a few of these, and he understands them really well:

TACH-ADAPT

Another, or additional way to go is an aftermarket CDI box. You can get your Bosch CDI fixed, then save it for a rainy day while letting your aftermarket box do the work. I have used Mallory HiFire Pro 695 on quite a few cars. It is semiconductor based, as opposed to the passive component based Bosch CDI, so it is more reliable and less expensive. It is also about the same size as the Bosch CDI, so you can put it in the same spot. GM HEI and Bosch VR distributors work on the same principle, so you just follow the HEI instructions to hook it up.

[spoke]

Originally Posted by SBK930

Dizzy out and green wire checks out ok.

Had the CDI rebuilt back in 2012 and it has not done a lot of klms since.

I have removed it to send away however is there any way I can check to see if it is ok ?

There are 2 wires in the green sheath. It's a coaxial cable. One center conductor and one outer conductor. You should measure from one conductor to the other and it should be an open circuit.

My 930 died 2 years ago for this exact wire issue. Some folks called it the "green wire of death". The insulation cracked off and the center conductor was allowed to touch the outer conductor and caused the wires to short and no spark and no run.

To properly measure this wire, measure from the CDI connector with all wires in place. You should see a couple hundred ohms which is the internal pickup in the distributor.

Here's a link to my thread of my dead 930:

https://forums.pelicanparts.com/911-930-turbo-super-charging-forum/1003065-86-930-cis-ignition-issues-seemed-start-when-alarm-issues-started-3.html