Kory-88Iroc 350 tpi

iTrader: (1)

I started running the motor with the serp belt on . My volt guage is reading like 16 volts. the battery is fully charged (tested with the car turned off and batt disconnected it read 12.96) I have the wire that is supposed to go to the alt light in the guage cluster run through a 500 ohm resistor then to power.
I thought that I had the problem solved. I found that the hot lead between the starter and batt was burned about half way through from rubbin on the header. I replaced it with a longer one that was run out of the way. I figured that it would take care of the prob. I started the car and the guage pegged again.
I need to check voltake at the back of the alt yet to make sure.
Any suggestions?
Thanks, Kory

TexasLT1

Kory, I thought only I had this problem. I cant remember what happened, but one night about a week after putting the engine in, I looked down and the needle was pegged. I turned around and headed home, and we think what happened is the regulator on the alternator itself just went out. what brand alternator are you running? stock? whetever you do, dont get the Ultima from O'Reily's, Im on my.....4th one now, I think, dont really know. We cant come up with any single reason why they keep going out other than they are just crappy alternators. atleast from O'Reily's you get a lifetime warranty so if it goes out, I just take it back and get another. wish I had more help than that but thats all I can tell you from my experience.

Kory-88Iroc 350 tpi

iTrader: (1)

Its a stock gm unit.
It could be bad I guess. The motor only has 7k on it though. It has been sitting for 8 years so I guess anything is possible.
Kory

Kory-88Iroc 350 tpi

iTrader: (1)

I checked the alt voltage with the motor running at idle.
From the bolt on the back of the alt to the battery negative was 19 volts.
Any ideas?
I then removed the belt just for kicks. The car ran on battery voltage at 12.5.
Kory

TexasLT1

damn Kory I dont know what to tell you. I havent had much experience with this problem so I dont really know. apparently mine was just the alternator. let me talk to my dad and see if he remembers if we did anything else when we put the engine in. I'll get back on here this afternoon if Ive got anything else for you.

Sparkee

It sounds like the regulator in your alternator went bad. I wouldn't run it too much especially if it has 19 volts at the alternator. You could burn stuff up if you do. Battery voltage with the engine off should be 12-12.5. With the engine running between 13.5 and 14.3. If you get 15 or higher, something is wrong.

I would recommend a new alternator. If you have the stock serpentine belt setup, Summit Racing has TPI high output alternators for about the same price as from a car parts store. Last time I checked, a rebuilt with 1 year warranty was $95 and a new one with lifetime warranty was $135. The Summit high outputs were $145. If you plan on keeping the car, you might as well get a good one to begin with. That's just my $.02. Have a good one.

mat89RS

I guess we all had this same problem, I had to change my alt. 4 times before getting something that was working decently .

TexasLT1

this makes no sense, there has to be something that we all missed, if only one us had this problem, Id just right it off, but since all three of us have, there has to be something going on. I didnt think alternators just go bad like that.

Kory-88Iroc 350 tpi

iTrader: (1)

I agree.
I was looking at the alternator schmatic. I think that it has something to do with the wire that is supposed to get power through the alternator light in the guage cluster.
I was told to use a 500 ohm resister in place of the bulb. I looked at the schematic , the stock one has both a resistor and a bulb. Maybe this would make a differance.
Kory

mat89RS

Well myself it was mainly because i didn't knew that much about alternator wiring. it's fairly easy, 1 big red wire that goes to a ceremic spliter that goes to the battery (you can't plug the red wire onto the battery directly because it needs to see the power in your wiring harness) Also 1 red wire that goes to the ignition box ( locate a big all pink wire) and a brown wire that goes to the starter solenoid with a fusable link onto it. that's it that all ... no need for 550ohms resistence on a LT1 alternator.

mat89RS

The voltmeter gauge on the dash is plugged onto a ignition feed. it has nothing to do with the alternator itself. the voltage your seeing is the power trough your harness. On my car the battery does not indicate exactly the same voltage as the voltmeter gauge. it's normal, there should be about .5-1 volt difference between the two.

TexasLT1

yeah, but 19 volts? theres no way it should be that high. thats exactly what mine did, peg out the voltage gauge, after we got it working. we also tried resistors, but as yall know they didnt work either. I dont know, I still think there is something we missed.

mat89RS

Well if you're getting 19 volts it means that the alternator voltage regulator is F*CKED ! there's no way a regular alternator can output that much when it's pluged, it's either charging or not charging ! trust me , I know !!!. if it's plugged correctly it will give you 13-5 -14-5 volts... if not well it wont charge