67 327 electrical problem

[jkern]

I just replaced the alternator, regulator, and starter motor. Wires are all on the correct terminals. I think I have a short somewhere. May or may not be related to the charging system. When I turn the key to 'acc', with no load, the ammeter reads -20A. If I turn on a load (like the lights) in that position, the ammeter reads -40A or more. If I turn the key to the 'on' position (no load), the ammeter reads -40A. The horn works with the key in the 'off' position. I think the relay is OK. To start the car I need a boost from a battery charger. It pins (-40A) the ammeter in start and then reads about +40A after starting and very slowly drops off to +5A as the engine runs. The engine is running very smooth. No smoke anywhere. I switched out the coil but no change. I charged the battery out of the car. Seems to take a full charge without indication of an internal short. It was reading about 14V after charge. Drops to about 12.3-13V as the engine runs. I have tried another alternator. No change. Pulled all the fuses. No change. All electrical loads seem to be working without problem. From the schematic that I have, it looks like the only components in the charging circuit are the battery, solenoid, ammeter, horn relay, ignition switch, voltage regulator and alternator + the harness. I might have a problem in the ignition harness. Could the ballast resistor be the cause of this problem? Has anyone seen this problem before?

 

[mcditalia]

Have you checked the battery's specific gravity? If the battery is shot it might charge ok initially but loose its ability to function properly very quickly. I've had some batteries that did the same thing right before crapping out completely. Try another battery and see if you get the same results. The horn is supposed to work with the ignition switch in the off position. You mentioned that you need to boost the battery in order to start the car. Is that because the battery is too weak? Does it loose charge while it's not being used? Does it loose charge while you are driving it? If you replaced the items you mentioned i would bet either the battery is the source of the problem (simple) or a symptom ( have a drain or short between the ignition switch and accesories being powered off it.

 

[JimVette]

Years ago I had a '66 327/350 and I had an intermittent electrical problem that drove me crazy. After a period of time I isolated it to the connections for the wiring at the firewall.

 

[jkern]

Thanks for your inputs. I have solved my problems. There were numerous problems mainly originating with a previous owner and his inability to read a wiring diagram.