Hi all,
I am new to this list so I have not seen a FAQ come by yet. If
this is a common problem that is already covered elsewhere please
point me in the right direction.
My 77B was behaving unusually well for about a month. I drove it
to the store on Sunday morning and when I turned off the key,
the engine kept running. I thought it was a mechanical key switch
problem. I could get the engine to stop by stalling it and it was
truly off--no power to the ignition at all. Later as I tried to find
what was wrong I discovered that eventually it will stop as it
runs out of gas. So with the key off, the fuel pump is off, the
radio is off, and it seems only the ignition is on.
Eventually, I figured out the ignition was being powered back through
the "ignition" light circuit. If I disconnect the sensor wire at the
alternator the engine stops. I thought it was an alternator that had
gone bad so I exchanged it for a rebuilt one. The rebuild unit had
exactly the same problem. I checked the sensor wire and it does
switch on and off with the key so with the key off, it should stop.
I checked the wiring diagram and could not find any diodes that may
have shorted in the ignition circuit. There is a diode in the
parking brake circuit, but I could not see how that would cause my
problem. I gave up and added a diode in the sensor line so the
alternator cannot possibly back power the ignition ever (key on or
off). Now it shuts off when I turn the ignition switch off.
Any ideas on what went wrong so I can fix it right and remove the
diode I added? Although it works now, I would rather fix it right
instead of adding parts.
As a side note, it seems that current rebuilt alternators only use
two wires instead of three. Two of the original wires went to the
same place, so they rebuilders only use the big wire and the sensor
wire. The third wire is left open.
Cheers,
Bill
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______________________________________________________________
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| / / Bill Kostka |
| HEWLETT/hp/PACKARD |
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| Interactive Broadband email: bkostka@rgv.hp.com |
| Products I am responsible for my messages |
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