Is everyone's alternator like this? 95 Formula 5.7

[superducky55]

Howdy guys.. I figured i'd throw up one last post in an attempt to figure out the charging issues on this car before i just blow it up

Basically here's the jist of it. When it starts up cold, the charging system works amazing and i'm 14.2v solid going up to 14.4
however, as soon as engine temp guage moves even just smidge - voltage starts to drop (i'm measuring with a voltmeter on the accessory line as well as the on-dash gauge, they both line up about =)

I've replaced everything. New alt, redid all the wire connects, new battery x 2, etc.

After engine heats up all guages read between 10.3 volts and 11.8 volts.. with no real pattern (heat i guess would be associated with it, as on these recent summer days its getting worse)

I have the upgraded bosch alternator. I swapped it to no avail.

Does everyone's system flux like this? I'd say its way more dramatic than it should be.

where else could i look for the drain / lack of charge?

Thanks in advance

[doodad]

it should be on 13.5 normally.. if your alternator gauge is moving like that that means your alternator is weak.. something is not right..

[Mr. Luos]

The reason you have more voltage when the car is cold is because it idles higher thus spinning the alternator faster.

Easy check....take it to Checker/VatoZone and have them run a charging system test. Free and you will know for sure if there are any issues.

[ikeyballz]

hm.. try doing what mr luos said..what if you try rev the engine to like 1.5K..and then check the voltage? does it go up? if not, maybe its the serpentine belt..have you tried changing that? if that gets sort of old..the heat MIGHT affect it.. also, i think the alternator goes through a voltage regulator before it goes to the battery, so you dont OVERcharge it..if that malfunctions, that may also cause the fluctuations..

[doodad]

Originally Posted by Mr. Luos

The reason you have more voltage when the car is cold is because it idles higher thus spinning the alternator faster.

that is what l thought too and even l typed but then l thoguht it cant be and l deleted.. because my car idles faster when the car is cold and the alternator is staying where is should be. when l rev the engine alternator doesnt move.

even my mechanic said (he is a very good mechanic) when the car is idling, if your battery gauge is moving forward or bacward, then that means your alternator is weak..

[Rmbodie]

Sounds like the built in voltage regulator is breaking down with the heat . I have an older car that sits sometimes 2 weeks between driving and it ussually has a very high voltage (14.5) at start up but as the battery voltage is recovered the voltage drops to around a steady 13 volts. If yours is dropping under 12 your alternator may not be grounded well . That would cause resistance (Voltage drop) , Which would force the regulator to drop the output voltage . Rob

[superducky55]

Thanks for all the quick responses folks appreciate it

Well this is my (Third) alternator, second BOSCH Premium one. They swapped it for me when i insisted it was a crappy one. I swapped the battery same day to eliminate that potential problem.
This new bosch alt does perform better at keeping the volts up than the last two.

I just replaced the serp belt last fall with a goodyear gatorback. But your mentioning it does bring back to mind the disaster i went through to do it, and it may give me a clue as to whats happening.

My local Murray's autoparts store gave me a belt for my vehicle which was SIGNIFICANTLY longer, i'm talking 6-8 inches, than it needed. I had 4 guys over there making sure we weren't missing a pulley or routing it incorrectly... checked it a million times. Luckily i broke down next to the autoparts store
however, I had to keep going back, probably 5 times, trying to get the right belt.. tried all similar year firebirds / camaros with a 5.7
finally, the one from a 2.0L 90's ford truck was giving me the correct tension.
Now i wonder if even that belt is slightly too big. Could somebody throw me the correct belt measure for the 95 lt1? sounds like something luos would know

Thanks again guys.. I'll take it up to the other autoparts store today and have them check the charging system once again, and perhaps have them pull a serp belt and see if they give me the goofy-long length or the correct one.