In a message dated 96-08-28 23:32:44 EDT, you write:
<< After taking my TR250 out for the first drive the yester day I
noticed a problem with the charging system. The car wouldnt start so I put
a fresh battery in. 20 mi down the road I had to push start it . Looking
at the alt. a little closer today I noitced that one of the wires isnt
connected to anything. Ther is a big plug with three wires: One brownand
yellow, One big brown, and one small brown. The small brown is the one not
connected to anything. It has been cut by a previous owner and has tape
on the end.
The wiring diagram in the haynes man says there should be brown
stiped wires coming out. Are mine faded? I cant see any color other than
brown on them.
Could thsi be the reason my batery doesnt seem to be charging?
Wher does this wire go?
>>
Chris,
First of all to see if the alternator is charging, with the engine running at
high idle - about 1500 rpm - a digital VOM across the battery terminals
should indicate a charge of 13.5 - 14.2 volts. That's Lucas spec for their
voltage regulators. Anything below that indicates a bad alternator or high
resistance in the charging circuit.
During these checks DO NOT, repeat DO NOT, remove either battery cable while
the engine is running.
While your at the battery terminals with the digital VOM, switch to the AC
range to check the diodes for leakage. On the AC scale you should only have
about 2 - 3 volts. Higher than that and you may have some diodes in the
alternator's diode pack going bad.
Wiring harness connections: The large brown wire goes to the "+" battery
terminal, usually joined at the starter solenoid. This wire provides the
actual charging voltage. The smaller plain brown wire comes from the wiring
harness to provide feedback voltage for internal regulators that are voltage
sensing (monitors available voltage in the car's circuit). It's quite
possible you have a machine sensing regulator (controls voltage developed
within the alternator) in you alternator. If that's the case, that wire is
not used. The brown/yellow is the wire that comes from the indicator bulb on
the dash. This circuit also supplies "exciter" voltage to get the alternator
up to full charging voltage as quickly as possible when the car is first
started. The bulb glows when there's an imbalance between voltage being
produced by the alternator and what's being used by the car.
Check you battery voltage first to see if the alternator is chargine. Check
for dirty connections. If you want, I can step you through determining if you
voltage regulator is machine or voltage sensing and step you through
diagnosis.
Have fun,
Charlie B.
|