Re: Alternator Voltage & Amperage (load) Testing

"LanceM" <[EMAIL PROTECTED]> wrote in message
news:[EMAIL PROTECTED]
> Last night noticed that my 91 Saab 900 at idle, with nothing on except
> for hazard lights, the fuel pump pitch noise was going up
> and down in perfect synch w/hazard lights on/off. Tried slightly revving
> engine but then could no longer hear fuel pump
>
> My alt V output is steady/good on both a scope (w/nominal AC ripple) and
> DMM, but has not been load tested, which will likely do. No batt
> charging or other known electrical problems [(all wires clean and
> secure) but ignition probs possible].
>
> Fuel pump fuse is 20A, with these type fuel pumps generally pull 6 - 10
> A (IIRC). Doesn't seem it would tax the alt in such a way. All fuel
> pressures, with exception of dead-heading pump (didn't do), are good
> (including while driving/bucking). Have hesistation/bucking problem
> which am t-shooting - just curious about this one FP phenomenon
>
> Anyone else ever notice this (or may just be an artifact)?
>
> i.e., is it possible for an alternator to put out good/steady voltage
> throughout the RPM range, per DMM or scope, but yet have
> current/amperage out drops, at narrow RPM range(s), that only a load
> test will pick up?
>
> Thank you,
> Lance
>
>
> Bosch 80A alt, w/new/tested good V output Voltage Reg and brushes
>
> -- 
>
> alancemor....AT..yahoo.....DOT...com
    May be just normal.  Remembering when Hondas first hit the states, when
one turned on the headlites, it put such a load on the engine, via the
alternator, that the engine rpm would instantly drop--and vice-versa.  I
incorrectly predicted they were not long for this world--this world being
the US.  Man, was I wrong!!!   s