930 ignition system troubles
 

Hello all, I was looking to see if maybe someone should help shed some light on this troublesome 1980 930 i'm working on. To give you some info the car has had a phantom ignition problem for some time now. At first the car would randomly not start, mostly when the engine was hot and a simple check revealed no spark. The oe cdi box and coil was replaced with new permatune parts. Seemed to be ok for a bit but then the problem came back.

The interesting part is that the car will sometimes fire and attempt to run just as they key goes from start to run. The cdi has 10 volts under cranking, and I am getting AC voltage from the distributor. The "green" wire has also been replaced because the insulation was broken near the base of the plug. The car will almost always start cold but after 5-20 minutes run time it will shut off and have no spark!

Any replies or advice would be appreciated!!

You didn't mention how many miles are on the car and IMHO, thats a key piece of information,.... :) :)

I'd be looking carefully at the ignition switch.

Car has around 100k. While the car is running I will fuss with the key and switch with no disruptions. I thought if the switch was faulty it would lose power to the cdi box but it has power when cranking. Here is a quote from permatunes site:

"If the engine does not start but kicks just as the ignition key is released from the start position, check the ignition switch start circuit. To check this circuit, place a Voltmeter on the power wire of the Perma-Tune and observe the meter while cranking the engine"

Not necessarily. While its not easy to do, you might "hot-wire" the car so that the ignition system receives full battery voltage while driving to rule that out.

This assumes that your battery, battery cables, alternator, and all associated wiring is in perfect condition, of course.

I had a similar problem on my SC. Would start cold, run for a bit and shut off. I discovered that the "magnetic pickup" the coil inside the distributor was the problem. Once it warmed up it would lose continuity.
I discovered this by... checking the ohms of the green wire when cold, I would get the proper ohms, as soon as the car died on me I checked and got nothing, waited a few ours and then it was good again.

Jay

the delayed ignition cut-off relay could be funky, like a wooley monkey. key on power goes through that on the way to the CD unit. it can be jumped.

Thanks for the replies gentlemen, I will look into a few things. This ignition cut off relay is something I am not familiar with because my repair manual is for a SC which doesnt show the relay.

Is the tach working correctly? I think the tach sensor wire is somehow tied into the ignition system and can cause problems if it is faulty. You may have better luck in the 930 forum, there is a War and Peace size thread over there about ignition.

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