Electrical gremlins

[Z28SSMAN]

A guy I met down at Super Chevy in Memphis keeps texting me about having electrical problems with his Fbody. Has had alternator rebuilt 3 times (not sure why he keeps doing that rather than buying a new one). Say it runs 13.7 volts until he hits 5000 rpm, then it drops to 10 volts then when it shifts and drops below 5k (has automatic trans) it goes back to 13.7v. I think its a bad alt. When you think about it, his engine may be at 5k but the alternator is probably spinning 3 times that speed.

[Titan5]

Hmmmmmm just my thoughts out loud, assuming it is a late model.

First thing I would think is that the belt may be slipping, the grooves on a serpentine belt do wear and can have an effect on grip, there is a small tool that can be used to check this, the belts can appear to be just fine and can be over looked.

Also with all the voltage and amperage draws on cars these days the alternators are pushed pretty hard under normal conditions, high rpm's in an alt. can cause diode damage or could cause them to not function properly which could I suppose cause a voltage drop at that time.

The wiring on the cars charging system is probably too small of wire to carry the load efficiently at higher RPM creating the condition also, it is good enough for regular use but not for continious high RPM's.

Something to think about, and don't even think about giving him my number cuz I can't text in short messages! :lol:

:smile tease: T5

[Z28SSMAN]

Makes sense. The guy is kinda different and does things kinda weird. I'd never take an alt in and have it rebuilt 3 times though.

[Titan5]

Makes sense. The guy is kinda different and does things kinda weird. I'd never take an alt in and have it rebuilt 3 times though.

I agree.



T5 :smile tease:

[MR.hp]

A guy I met down at Super Chevy in Memphis keeps texting me about having electrical problems with his Fbody. Has had alternator rebuilt 3 times (not sure why he keeps doing that rather than buying a new one). Say it runs 13.7 volts until he hits 5000 rpm, then it drops to 10 volts then when it shifts and drops below 5k (has automatic trans) it goes back to 13.7v. I think its a bad alt. When you think about it, his engine may be at 5k but the alternator is probably spinning 3 times that speed.

I would think the regulator is going to keep the alt from overcharging hence the reason for the lower voltage. One thing I do know is that the later model alts like on the Camaro put out more amps on less voltage. Remember when I told you that I switched over the Race Car to a late model alt ? and that cured all my electrical problems. I think after 3 rebuilds I would ask if the regulator ever got replaced. Rebuilt alts are cheap around a $100, if it were my car I would try that first.