I have a 01 C5 CPE A4. Started dropping charge on DIC to 10.5vdc. Alternator is a 145 Amp 14 Volt GM/Valeo w/ clutch pulley.

Have a Red Top 900 cca battery that is 2 years old. Went to Auto Zone and the guy swapped me for a brand new one even though mine showed to be a good battery (a friend).

That was not the problem. Went and bought a new still in box Valeo 145 Amp 14 vdc alternator w/ clutch pulley ($617.00).

Now it charges at 13.5v running and battery is 12.6v when not running.

PROBLEM!

Getting HIGH VOLTAGE on DIC. It is so high it trips my hvac lamps and cluster lamps in gauge bezel for protection I guess. When it gets down to about 15.5v the gauge lamps come on as well as all the gauges.

I have never cleaned the grounds on this vette sice I bought it new. I should have done this first before spending 617.00 buck on an alt.

Also, my left blinker blinks 3 to 4 times faster than normal. The right blinker is fine. No bulbs are out. Is this a clue?

One more thing, Do I need to disconnect my neg. battery cable before disconnecting the front 2 grounds near the headlights on the frame?

This is my daily driver and cannot get to work. Help needed.

Thanks,
Darrell-

 

Hi, First, it is always a good idea to unplug the battery when working on the system. It is not imperative to unplug the batt to clean grounds, but it is a good idea, because you can get some spikes when disconnecting and reconecting the grounds to frame.
Also make sure that all the cables are tight and clean at the batt, alt, starter lug, and the fuse block underhood.
You should check what the output from the alt is with a voltmeter at the large red output wire to confirm that the guage is seeing an actual overcharging event. If it doesn't match the guage, there is a problem with the ipc. Then measure the volts at the sense wire, it should read battery voltage with the engine off, and charging voltage with it running. If it reads true, you probably got a bad regulator in the new alt.
Good luck

 

Sounds like you have the wrong alternator installed. The "stock" alternator is rated at 110 Amps.


Here are the correct part numbers for the alternator .....

1997 - 2000 .... part number... 10316182

2001 - 2004 .... part number... 10353440

Check that you have the correct part installed, the wrong part will definately cause problems.

 

So you are talking about getting a voltage measurement (in dc on my Fluke 179) from the B+ stud on the alt. to the neg. terminal on the battery correct? This should read within .5 volts of what my DIC is showing?

The sense wire is which one on the alt.? Where does the other lead from my meter go to? Sorry, I am new to this.

The IPC is a module that controls the cluster gauges and lighting?

Let me clean the grounds I can get to under the hood including the one at the fuse block near the battery first. Be back this afternoon to report about it.

Thanks,
Darrell

 

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This alt. is from the Chevy dealer and is an exact better replacement than the 110amp 14volt 10353440 because of issues of throwing code p1637 & p1638 codes. It is GM/Valeo with the clutch pulley, the pulley helps a lot for the loping cam I have installed when idling.

If the grounds dont fix it, I will have GM recheck the alt again.

Thanks,
Darrell

 

I'm not sure why you think the alternator you have installed is a "better" replacement when it is throwing codes ......

The PCM monitors the vehicle's electrical system. It is looking for occasions where the vehicle electric system is either running on a voltage that is to high, or to low.

Once you start modifying the basic system (underdrive pullies for example) you're on your own ... good luck finding an alternator that produces the right amperage/voltage to keep the PCM happy.

 

The GM/Valeo 145 amp 14 volt alt. was installed on my 01 C5 in 2003 from the dealer. The new alt. was not the problem, it was something else they found a few weeks later. I have had NO problems with the 145 amp 14 volt alt in the last 5 years till now. The alt. tested bad so I bought a new one, and got a new red top battery.

I dropped 10k in engine mods and external mods from MTI in Houston, Tx. They suggested this was a better alt. for me since my vette has such a big cam lope at idle.

I just go with what I have been told, I am no electrical engineer. The last 3 or 4 times I drove it I did not get a HIGH VOLTAGE on the DIC, only Service TCS, Service Active Handling and Service Engine Soon.

So I guess Your sayin I need to go to GM and buy a 110 amp 14 volt alt now correct?

 

I am an electrical engineer. The only reason the alt would over voltage is if there was a failure in the voltage regulator or bad connection in the regulators voltage sense path. I'd check the wiring around the alt first.

As for amp rating, it doesn't matter if you install a higher amperage rated alt, voltage regulation is a different control loop.

 

Oh yea, can't stress enough that you need to use a voltmeter to verify the over voltage is real. Use you Fluke with the min/max feature turned on.

 

So you are talking about getting a voltage measurement (in dc on my Fluke 179) from the B+ stud on the alt. to the neg. terminal on the battery correct? ( yes) This should read within .5 volts of what my DIC is showing?, (the closer the better tells you that the connections are solid and the grounds are good).

The sense wire is which one on the alt.? (should be the lower pin on the 2 pin connector, neg lead to any ground)

Sense wire?
You are talking about the plug w/ seal around it that is on the top of the alt.? Mine has 3 pins, not 2. This one is on the plug that is fixed to the internal rectifier on the alt.

I want to start testing this stuff over the weekend but am a bit confused on the sense wire and where to test from. hence the vette is idling or with the vette completely off w/ no key in the ignition.

Possible there is a diagram or pic of this wire?

Thanks,
Darrell
RIP Stevie Ray

 

Hi Darrell, Read through the recent posts-link below, you'll learn all you need to know about alt testing complete with some schematics. It's a long thread but I guarantee it will be worth your while .
Good luck
http://forums.corvetteforum.com/show...767&highlight=

 

I got my Fluke 179 out and tested just the battery. It was 12.65 vdc.
Hooked up red lead to B+ on alt. and black lead to battery neg. terminal. Set it to min/max auto sensing dc voltage. Fired the vette up and it read a max of 14.5 vdc and a minimum of 14.39 vdc, average of 14.4 vdc.

I turned on ac, rear defogger, headlights while it was running, the read out on the multimeter dropped 0.2 vdc only

Got in the vette and looked at the DIC battery voltage while dmm was reading in the 14's, and my DIC read from 12.9 to 13.4 vdc.

Why the difference in readings?

I read from positive on battery to all the grounds I could reach, they read the same as the battery did from terminal to terminal.

This alt. is charging great in real time it seems? right?

 

Hi Darrell, the question you are asking is discussed at length in the thread that I gave you the link to. Some really great input from a lot of smart members, give it a read and you will get insight into what to test next and the possible answer.
Good Luck

 

Okay, took the vette out on I-45 to see what the charging was gonna act like. Within 30 minutes my DIC voltage dropped to 9.5v and the engine started banging out, then died in heavy traffic.

Called the dealer where I bought it (Monument Chevrolet), and they sent a long flatbed wrecker. Did not hurt the vette... **whew*

Their vette tech found that the positive cable that goes to the starter was exposed to heat so many times from being close to the header tubes had become burnt and was brittle. They had to drop the header down on that side to replace it correctly. He replaced it with a thicker cable and added some heat shielding around it and reinstalled the header.

No more codes! Charging at 14.85vdc at the alt. and 14.5vdc on the DIC. With the ac, rear window defroster, radio, wipers and headlights on it is charging at 14.4vdc on the DIC. That 145 amp alt. is quick to adjust the voltage when needed. Had a new belt installed as well.

He also found a bad passenger side door module (computer?) that was bad. Had a problem with unlocking that door. He cleaned both right and left door wiring connectors, as well as bcm and pcm connectors.

With the GMPP, I was out of pocket $100.00 deductable plus $8.00 tax on a 2009 Pontiac G6 GT rental car. They even detailed it for me.

I pick it up Tuesday because of Hurricane Gustav, possible Wednesday if the rain has done any flooding.

Thanks for all your help,
Cross my fingers!

Darrell

 

Hi Glad you got it figured out, Your circumstance is a Perfect Example why troubleshooting these type issues has to start with inspecting the battery for a good charge, and the cables for cleanliness, tightness and integrity.
You can't take the cables for granted.
Thanks for posting your fix, it will help others..
Good Luck