In a message dated 97-07-31 01:37:26 EDT, up497@freenet.victoria.bc.ca
writes:
> I am still having teething problems here. The lamp that is for the red
> light was burned out, this was probably my main problem. I swapped the
> turn signal light for it, and it glows but will not extinguish unless I
> rev the motor up to about 3000+. When it winds down again the light
> *stays out*. It will come on again if the revs drop too low. Am I
> working with a paranoid alternator here?
>
> Revving the motor again makes the light go out. I have also swapped
> innards in my alternator, I used the pieces from a 55amp Chevette unit.
>
> Must also mention that the Chevette has this problem too, but it never
> comes back, and I hardly need to rev it at all to make the light go out.
Malcolm:
There are too many variable to say for sure, but in general, with no heavy
load, the light should be out at idle. A lot depends on the relative sizes of
the pulleys involved. If the alternator pulley is too large, it may not be
spinning fast enough at idle. OTOH, it's not unusual to need to rev them up
to get the light to go out the first time.
> When the lamp glows there is only about 5 volts between the lamp lead and
> ground. I have a feeling that I'm losing voltage somewhere in the
> system, any guesses?
Wher are you measuring this voltage? From which side of the lamp - the
ignition switch side, or the alternator side? You should get 12 - 14 volts on
the key side, but the alternator side will vary depending on the rpm. At a
high rpm, the voltage should be 12 -14 volts on the alternator side.
Remember, the higher the voltage on the alternator side, the less the lamp
glows.
Some one on this list suggested that you take the alternator to a shop and
have it tested (I'm sorry, but I deleted the post, and can't remember his
name). I think that is an excellent idea. Testing the alternator at the store
is completely independent of how you had it hooked up. Once you know what
condition the alternator is in, it will be a lot easier to troubleshoot the
rest of the car.
Dan Masters,
Alcoa, TN
'71 TR6---------3000mile/year driver, fully restored
'71 TR6---------undergoing full restoration and Ford 5.0 V8 insertion - see:
http://www.sky.net/~boballen/mg/Masters/
'74 MGBGT---3000mile/year driver, original condition
'68 MGBGT---organ donor for the '74
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