[dalco_100]

Dalco_100
Hello, need help w 67 GTO electrical problem plz.
Intermittent no 12v to distributer (MDS). Determined MDS is fine when hotwired. Issue chased down to inside of bulkhead / ignition switch. Unable to locate electrical manual, however have 1 page schematic showing all electrical systems. Ignition switch has been replaced and appears good (12v to dist and gages). Is there a typical known issue w this make / yr? Dash is out and next step is open harness between ign switch and bulkhead, which I would like to avoid. Schematic shows known splice for ign and gages, however no location (assume is in electrical manual). Also, no issues w gages. Any suggestions greatly appreciated.
Thx!

[Goatracer1]

I have a 1967 and never run into that problem. Are you using the resistance wire to power the MSD? Does it need the resistor? If not you could run a wire directly from the switch.

[dalco_100]

Hello Goatracer1,
Thx for the response. To answer your question, the resistance wire was replaced w a new harness that has constant 12v, which is what the MSD requires. I would add that I have driven this car for years and not had a single issue w ignition til now. I like your idea of a wire from the switch, which I have a wire ran to back of bulkhead to the distributor that works for now. I was trying to determine if there was a known issue so I could repair at the source. Thx again.

[JSchmitz]

There should be a ignition switched male spade terminal in you fuse panel. Just make sure it stays hot while cranking the engine over. Ran into that before. Terminal would drop out in cranking position.

["QUICK-SILVER"]

Just guessing "MDS" is suppose to be MSD??

So is the MSD a distributor? A box? Both? Stock distributor with box?

My first look would be at wire connections/splices that are not factory.

Need more info
Clay

[dalco_100]

That is a good idea. I will look into that. Thx...

[dalco_100]

Just the distributor. No box. Good suggestion on the electrical connectors. I covered that, including extra ground from block to dist to firewall. When I bypass ign circuit w 12v, the problem goes away. I also installed another MDS dist and still same issue. Thx for your help.

["QUICK-SILVER"]

How many wires do you have going from coil (+) to the bulkhead?

The wiring diagram I have shows IGN-1/run and IGN-2/crank are seperate from the ignition switch all the way out to the coil.

Not uncommon to lose coil (+) power while cranking if you don't have IGN-2 hooked up.

Clay

[dalco_100]

Clay, both ign 1 and ign 2 are good. Ign 1 loses volts intermittently, so I have it jumped at the fuse block until I find source issue. The car always starts right up, however running (ign 1) is where the issue comes from. Seems worse when car has ran for a time (temp dependent), however it sometimes misses / quits only minutes after running.
Thx

[dalco_100]

JSchmitz, good suggestion. I know the spade terminal you speak of. Just need to see if it's hot during crank. Thx..