Voltage discrepancy

I am troubleshooting my 1978 928 ignition system and have reached the point where I am checking and comparing the voltage at the ignition control unit plug Terminal 15 with the battery voltage. Shop manual trouble shooting says these voltages should be the same. My battery reads 12.03 volts while the ignition cotrol unit plug 15 reads 11.83 volts is this significant enough to warrant futher readings back to the ignition switch to determine where the voltage drop is occurring? Manual says they shoul be the SAME not an acceptable range. Any comments are greatly appreciated. Best, Greg

I don't have the answer, trying to find someone who can help.

Just to clarify, are we talking about a total ignition failure that you're troubleshooting for? If so, I don't believe your findings would explain a "no spark" fault because your ecu is being energized.

KilnRed,
Thanks for your reply. I thought 11.8 volts should be sufficient but wasn't absolutely sure because I've had an intermittent no spark/no start problem for awhile. I continue to work my way through it and the car started again as I troubleshooted it again. It's a real pain in the neck and too difficult to explain in writing --lots of troubleshooting over the years without uncovering the problem only to have the car start and run again for 6mos or so and then not start again. I'd like to discuss on the telephone if possible or convenient for you if you have some experience regarding the ignition system. If you don't have the time or interest that's fine. My tel # is 212 360 1295 if you call and don't reach me please leave a convenient date/ time for me to call back. Thanks again for your helpful response. Best regards, Greg

The ignition on your car is identical to mine, though, it is an '84. The most common fault for a no spark condition on our cars is the infamous "green wire." Have you inspected it or are you aware of the wire that I'm referencing?

Yes I have addressed that--replaced green wire more than once only to have problem return again months later. I have ordered from 928 intl an ignition switch . My problem seems to have the ignition switch as the common denominator. Hopefully that will solve it.