my 91 s10 blazer 4.3 TBI has low volts plz help cant figure it out
 

my 91 s10 blazer is running on 9 volts instead of 14 and i've tried a new alternator new battery new distributor cap and rotor and new plugs n plug wires and still nothing what could be the problem??? im stumped i need thoughts please...

Check grounds (battery ground which is located behind the battery on the firewall) and the engine block ground which will be on the drivers side rear of the engine.

Also, rule out the gauge being faulty... if you were really running at 9v, everything would be so dim an unusable.

Get a digital multimeter and with the truck running, check the voltage at the battery.

i checked the battery ground on the firewall n it was good but i def didn't think about the 1 from the block. and everything is very dim and my truck is very sluggish. when i check the battery with the multimeter it should be reading 14 or 15 right?

It should read around ~14 when charging/running. Does it crank up good, or sort of lethargic? Make sure all battery cables are in good shape, wouldn't hurt to clean any suspect electric points. Did this issue just occur out of the blue?

yea this all came out of no where i was driving it 1 day and the volts dropped and started to sputter and miss a little bit then the volts would go back up and it would drive fine then the alternator bracket busted off so i replaced the alternator and battery and after i did that now the volts woln't go above 9 or 10 volts and it did start sluggish or not at all right after i changed the battery and alternator but then i did the plugs, wires, cap and rotor and now it starts right up no problem but runs sluggish when i hit the gas and the headlights and dash lights are dim and the battery terminals and terminal wires are new as well im so confused at this point

There are a few things that come to mind. Even if the ground looks good, unbolt it and clean it, do that to the one on the firewall, and the battery ground on the core support behind the battery.

When you give it gas, what happens? Does it run normal and does the voltage go to normal?

How are you checking the voltage, are you just going by the dash gauge?

yes im just going by the volts on the dash for now because it was right all up untill the alternator went so by it reading differently im realizing i need to do more to see if it is right or wrong and when i hit the gas the volts stay the same and it kinda feels like its building up to go forward like ill hit the gas and it is sluggish at first and then it will gain a little more power but not much more