Working on my car today turned ign off and the car ran on for about 10 seconds before shutting off. Noticed that when ignition is on, the battery voltage dropped by 0.6 volts. Removed Battery and had it checked by a mechanic who pronounced it good. Cranking amps are at 95% of the original spec of 540 and batt voltage was 12.6 at rest.
By removing fuses I have traced it to the alternator excite feed wire from the ignition switch. I removed the ALt excite wire from the alternator and checked the wire itself, it has 0 ohms resistance and all connectors are free from rust. With the wire removed from the Alt, the batt drop at the gauge is less then 0.2v.
So it appears that when the alt excite wire is connected to the alternator it pulls the battery voltage down by 0.4 v with ignition on. Is this normal or is my alt on its way out ?
It stills charges at 14.7v, and I don't know why the engine ran on after selecting the ign off.
By removing fuses I have traced it to the alternator excite feed wire from the ignition switch. I removed the ALt excite wire from the alternator and checked the wire itself, it has 0 ohms resistance and all connectors are free from rust. With the wire removed from the Alt, the batt drop at the gauge is less then 0.2v.
So it appears that when the alt excite wire is connected to the alternator it pulls the battery voltage down by 0.4 v with ignition on. Is this normal or is my alt on its way out ?
It stills charges at 14.7v, and I don't know why the engine ran on after selecting the ign off.