Alright, the batt and alternator are good on my car, it's just when the car is running, the batt guage reads like 10 volts and the rpm's and the mph guages jump up and down and the ses flashes on and off sometimes. Remember the alt is good and someone told me a bad ground but what I've checked the are all good. What could be the deal.

 

Could alos be a short in the gauge cluster its self

 

Use a multimeter to check for voltage at the back of the alternator. Should be around 13+ volts. If you only have 10 volts at the alternator, you have a problem there.

Is the alt rebuilt? It is common for the voltage regulators in rebuilt alts to fail.

 

The alt is good, taken it off and had it checked out. The batt is good and when I hook up a batt/alt checker it reads 13+ volts out of the alt and 12.9+ out of batt. Ive used two diff batts and the same thing. I know it's not the cluster because the engine performance is also effected when the rpm's and speed jump, in other words it's like if the alt was bad but it's not. I was thinking it could be the PCM because doesn't it distribute all the power to the whole system. Plus if the alt was bad and I put in a fully charged batt and/or jumped it with another car it would read higher reading on the guage but it all stays the same and still jumps around like it has no power. It may be a short somewhere. Just started doing this. Anymore suggestions? Thanks

 

Sounds like a bad ground somewhere.
The voltage at the bat should be 13.8-14.2 at about 2000RPM's. Same at the ALT maybe a tad higher. If it is charging but won't get to that voltage without revving it then the reg is bad/not the right one,ect.
It also could be a relay dropping in and out somewhere. The ign switch can cause that too. Wiggle your key a little doing it a little like ya were trying to start/shut off the car.

 

Did you say regulator?

 

Yea
Voltage regulator.

 

If im not mistaken these cars have the built in voltage regulator in the alternator. I replaced the alt and it wasn't it. Returning the alt and I am going to try a new PCM. I am not sure what it is. The grounds all check out, this is just a wierd prob.

 

If the SES light has triggered you might try getting the car scanned. Perhaps it set a trouble code. But it sounds
like a voltage reg. problem.

 

Is the reg external? I dont think it is, i think it's built into the alt.????

 

Just as I thought, the regulator is internal in the alternator, so when I put the new alt then it came with a new regulator so in other words I dont think that could be the problem. What grounds should I check?

 

With some of the rebuilt alternators they put a reg in them that will work but is RPM sensitivity. That is why I said it may be the alt.
If ya got one just like the one ya had then it probably has the same type of regulator.

 

Well I guess we got that alt thing out of the way. I was thinking it may be the PCM because now that I remember, I took the car to get the code read and he said the car wasnt getting power to the computer connector, so maybe the computer is faulty, couldve gotten wet or something? I took it later that day to another guy and it read good. Don't know, i'm totally lost here. Batt/alt good and charging, the batt is charged, the guage says it's dead and the car acts like the batt is dead but the batt is fully charged. ???? Thanks for the help.

 

check your grounds on the block and on the passenger fenderwall