random voltage drop
#11
08-02-2011, 01:07 PM
alt output is the same as at the battery. it just randomly drops down real low for no reason and the engine stumbles, then revs up and the volts come back. theres nothing else turned. forgot to mention the belt and tensioner are also new and in good working order
p.s. not concerned at all of the innaccuracy of the gauge. its gm, i expect it
p.s. not concerned at all of the innaccuracy of the gauge. its gm, i expect it
Does the voltage drop cause the engine to stumble?
Or, does the engine stumble cause the voltage drop?
I would bet that the answer is closer to the latter. If the engine stumbles, the revs drop and the alternator will have a reduced output. Alternators won't put out rated voltage if they spin too slow. It is one of the reasons that underdrive pulleys can cause low voltage at idle. Even if the alternator were completely dead, as long as the battery was fully charged, the car would run normally for a time.
I would try to see if I could find out what was causing the engine to stumble.
#12
08-03-2011, 06:33 PM
im sure the stumble is caused by the cam and lack of tune, but the voltage drop occurs before the engine stumbles. i was thinking the ecm is acting up and trying to control the idle, but somehow overloads itself and drops the voltage out, which takes away from the ignition system and causes the engine to stumble. now why the ecm is doing that, im not entirely sure. should have the tune in it within 2 weeks and will see if that changes anything
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