i have a 88 fc na, i dont have any mods its all the way stock, my voltage reader says im running 8 volts which is all the way at the bottom of the reader... i think its my alternator, the car starts and runs even with the voltage being at 8... i cleaned and tightend my battery cables and still 8 volts the weird thing is i took the alternator to checkers "could be a mistake" and they say it passes.... and i did a do it your self test on it with a screw driver to the back of the alternator to see if it would stick to it... nothing it would not stick to it any where on the alternator... which it should right?? im pretty sure its the alternator but would feel stupid if it was somthing simple to fix.... any ides??? please help

 

Do you have a volt meter? Test battery voltage across the terminals. With the engine off, you should have ~12.5V. With the engine running, you should have about ~14V. You can also test between the alternator post and negative battery terminal. You should also see about 14V between these points, as long as the engine is running.

 

ok i will test those post as soon as i get a volt reader, but what do you think about the alternator??? judging upon what i posted do you think the alternator is bad???

 

it's very difficult to diagnose without knowing what the voltmeter says. i can tell you that when my alt went out on my s4 the batt gauge never showed any problems, and the alt passed the test at the napa here.

 

k so my voltometer says while the engine is off from across terminals im gettin ~12.2 volts, while the engine is running across terminals im gettin ~14.8 volts, and from the alt post to the negative post im also gettin ~14.5 volts. so things seem normal, and another weird thing is my volt reader in my car is now working??? strange, im thinking it might be just a glich but it seems that my car is gettin the right power im not really sure what to think

 

Does the gauge still say 8 volts? The contacts on the circuit board could be corroded, which would increase resistance and decrease the voltage reading.

 

i'm no expert, but could all these little electrical problems be caused by a bad ground?

 

the gauge in the car is saying im putting out ~14v now, but like i said before it was reading ~8v, thats why i find it so strange that now its all the sudden working?? i should add that i did remove the alternator and take it inside for a couple days and then took it back out and hooked it up "maybe the plug on the back of the alt was loose or something" but when i put it back on, started the car, it started working??? where is the circuit board at, and how do i go about checking the contacts for corrosion?? maybe its a bad ground im really not sure im kinda stumped??? and thanks for the help so far guys

 

A bad chassis ground or grounds causes reduced voltage/current to everything. Dimming lights, etc... That's not where I would be looking, but it never hurts to clean existing ground connections.

If the gauge is showing 14V now, I wouldn't worry about it. The circuit board I was talking about is on the back of the instrument cluster, but if the gauge works, I'd say leave it be. My guess would be that either the wire to the B-post or the plug on the back was loose and causing a random problem. One of the wires on the back powers the voltage regulator.

 

i will look into those things,hey thanks for everything guys ill keep you you posted