So I am checking the power wire off the alt and the power off the battery witha meter?

 

Car is running.

On the back of alternator, heavy red wire (+) and any ground on car. Get reading of volts.

Do the same with positive post of battery. They should be the same. If not start checking your wiring.

If they ar the same, it's tech2 time.

 

Sounds good.

I dont know what other wiring to check, how about the ground on the back of the head. Possible that could cause all this drama? I might at some 2awg grounds for ****s too.

 

What other codes are you throwing ?

 

Not totaly sure for some reason I cant access the codes. Options and fuel x4 isnt working. I can see on my dash that the ABS is acting up and active handling. But codes, not sure.

 

Have you tried this with the doors closed ?


The "diagnostic display" mode is entered with the following procedure:
1. Turn on the ignition but don't start the engine.
2. Press the "reset" button to turn off any warning messages
3. Press and hold "options" and
4. While holding "options", press "fuel" four times within a 10-second period

 

I got it working today and the codes I got where:

P1637
P1638

And it seems that (ajg1915) or Tony, you have commented on this topic before so I appreciate your help. - http://forums.corvetteforum.com/c5-t...sket-swap.html

So I guess I will check the voltage and go from there, still a bit confused on a solution.

 

What's wrong is that your PCM is what controls the charging rate and it needs to be adjusted using a Tech2 to sync everything up.

 

I have nooo idea where I can get my hands on a tech2. So its electrical related and not hardware like grounds?

 

You need to go to dealer or shop that has a tech2.

 

Send a PM to BIll Curlee

 

I picked up a mutlimeter today I think im going to check the ohms threw this charging diagram that I have and then I guess Ill put my exhaust back on and start it to get the battery/alt readings.

What is "Bill's" usnername?

 

http://forums.corvetteforum.com/c5-t...tion-long.html

 

The charging system runs through the starter solenoid connections. Disconnect the battery and use the ohm meter and read the terminal connection on the BACK of the alternator Connect one lead there and the other lead on the disconnected positive battery terminal. There should be pretty close to zero ohms in a perfect circuit. Read and record the resistance readings.

Hook everything back up and start the engine and use the DC Voltmeter to read the battery voltage. Read directly on the battery terminals. Record the voltage.

Read the voltage on the back of the alternator to ground. Record the voltage.

Find a set of battery jumper cables. Connect one wire of the jumper cables ( it doesn't matter what color you use ) and connect that single cable from the alternator output terminal on the BACK of the alternator and the other end of the cable to the positive battery terminal. See if you still have your charging system fault.

The connection and wiring on the solenoid frequently go bad and get brittle and burnt. This will cause a voltage drop and charging problems. I seen this problem probably 10 times on various C5's

If nothing else, clean and examine the connections at the solenoid and make sure there tight. The wiring on the solenoid also has a fusible links in-bedded in the wiring. It also could be part of the problem. Look for a bump in the wire and a place where the wire changes color.

Bill

 

Ok a quick update:

I got a decent mutlimeter today and got a few readouts.

Battery itself :11.6-7
Circuit from ALT power to battery power is: 0.00 ohms

So that tells me that there arent any breaks in the charging system wires itself right? I am starting to think i just have to weak a battery for this car. This is the battery out of my 93' camaro and I never had issues with it.

Tony.

 

Alternator is what supplies power after you start. If the battery is cranking you got enough jucie. See schematic below.

 

Ok, I understand the alternator charges the battery but if the resistnace test shows that its ok then the wiring 'should, be ok I would think. I am putting my exhaust back on right now so I can test the alt with the car on.

 

The second schematic shows you that the charging rate is controled by the PCM, like I told you to begin with.

You just keep on ignoring this. I'm just trying to help. I was very puzzled like you when I got the same problem on my car when I did a bunch of wiring, gauge changes, etc ... on my project vette.

It took me a few month of on and off research to figure out that the gage inside the car is controlled by the PCM and not directly linked to battery.

I checked the voltage using the DIC volts not the gauge itself and then checked the output from the battery and the alternator.

I was getting 14V on the alternator and battery, but only around 11.5 and less on the DIC. After much time and research I figured out it was the PCM causing the problem.

Go to the GM delaer with Tech2 and explain problem. Should be a $75 buck repair.

Once my car is done that;s what I'm going to do.

 

Tony,

I am not 'ignoring' what your saying but this isnt the only place I am geting info and it seems that 80% of the time its not tech2 related.

And in my case I am getting 11.6 at the battery and unkown at the alt because i took it off to put the exhaust back on. So even before the car is on with a brand new battery its 2.9v off.

 

The alterntor and battery voltage should be checked with the motor running. If you have a difference between the two, then you have a wiring problem between those two locations.

If there is no real difference between them, then it's the PCM. I wish you were closer as it's always easier to deal with these types of problems.