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Issues experienced right now
Power loss 13.4v when car starts, but the longer the car runs the voltage will drop. It goes from 13.4 down to 12.6v with car running 100% idle for 5 minutes.
I have had 2 alternator swaps and 3 batteries installed in 7 years and still these issue persist to this day
Door locks and windows quit working at random,
I have to open the door and reshut the door one or more times again then the power door switch on the drivers side will start working again. Passenger side works without any issues.
Alarm will go off constantly or randomly if I have a battery in my key fob, no matter if its a new key fob or not.
Sometimes when I start the car the security light on the dash stays on othertimes it does not. I think the alarm is somehow draining my power constantly.
Sometimes when I goto start up the car it fires up and sounds right. Other times it starts, but its not near a smooth of a start at idle.
Service traction control light appears randomly while driving or when I first start up the car or when I am backing up in reverse. Again this is random.
Other issues:
I can drive car somewhere close for 2-3 minutes. Go in grab something, goto start it up and their is no power inside whatsoever. No dash lights, no ding, no compressor or fan at all.
When this happens I usually pull the key wait 2-3 minutes re-insert the key turn it and the car will start normally.
This issue also happens randomly, but its more present when I start up and go short distances for quick errands.
Past issues I haven't seen in a while, but I have experienced since I have owned the car for 7 years
REDUCED ENGINE POWER - I have only seen this occur 3 times: All 3 times was on the stock alternator.
If I let the car sit, wait 24 hours I could go out, insert the key and the car would start.
Past issue solved:
Battery would drop while sitting idle at red light, car would eventually shut off after driving for 20 minutes or running idle for 20 minutes.
I would have to keep on revving the engine while waiting at a red light or the car voltage would keep dropping and the car would die.
Cracked coolant tank was FIXED.
C5 Z06 alternator was replaced with a used C6 alternator at shop.
Voltage drop still present, but car no longer stops running between 20-25 minutes.
Voltage drops, but the car doesn't shut itself off anymore.
Service traction control light randomly appearing issue:
FIXED by having the vehicle re-tuned at tuner shop.
Went away for about 6 months. PCV line had to be fixed too. Car was running LEAN... FIXED
If I don't let the car run idle for about 3 or 4 minutes before driving off.
The engine rpm winding down is much slower than normal until the car has been driven a few miles. Then it winds down normally.
I asked the tuner and he said it was due to the cam. I hope this is true, because otherwise it worries me somethingelse could be wrong.
After the vehicle gets re-tuned the engine RPM winds down normally at all times for about the first SIX months, but it loses its tune eventually.
Once that happens I just go back to get the car re-tuned again. That seems to take care of the service traction control light for another six months.
Also when I press on the power door switch at night while driving the lights will dim just a bit.
Thats about it, now you know every single issue currently happening with this car.
Car Details:
2001 Z06 Corvette w/ Cam\
Manual transmission
For any voltage drops like this on the charging system I would do a voltage drop check on the positive and negative sides of the charging circuit !!..videos below !!
Your fourth line could be a clue......"two alternator swaps"....these cars don't like different alternators, which is why we suggest a rebuild and not a change.
1) Have you checked the ground connectors for corrosion? C5's are notorious for having electrical grounding issues.
2) Next time the window won't roll down, try wiggling the bundle of wires coming from the door. If that solves the issue, clean the wiring connectors and give them a dose of dielectric grease to keep it from happening again.
3) If you clean all the connectors and that still doesn't solve the issue, you may have a bad BCM.
The "losing the tune" issue may or may not be a separate issue. You said the car idles high when it's cold (engine "winding down" slowly). So the problem is occurring when the car is in open loop mode. Check your intake vacuum lines for leaks and cracks. Or, it could be related to the electrical issues, one of the sensors may be throwing a bad reading because of bad grounding.
Do you still have your original alternator? If al else fails you might want to have your original alternator re done. It has mentiioned a number of times on this forum about the negative consequences of replacing your original with a replacement.
I don't have my original alternator anymore, so what would the best option be? Which alternator works properly on a 2001 C5 Z06 without causing any issues.
Last edited by Mike's2001-Z06; Oct 6, 2020 at 12:41 PM.
Many times a car idling high in cold weather is a vacuum leak in a hose because in cold weather rubber shrinks and the cracks open. One way to test is to spray test
2000W amp and no upgrades to the electrical system? I would start there. Easy debug. Disconnect the amp and see if the problem goes away. Also I second the "check the grounds" comments above. On another car I had a bad engine ground that caused a large voltage drop.
For any voltage drops like this on the charging system I would do a voltage drop check on the positive and negative sides of the charging circuit !!..videos below !!
OP you didn’t indicate how long you’ve owned the car.
#1 did you install the after market radio and other items?
#2 is it possible that the car has been in a flood - these cars grounds are very sensitive.
#3 is this your 1st Corvette - C5?
#4 as stated these cars don’t like having their alternator switched out - unless it’s an exact OEM replacement.
#5 what is the car’s mileage - history - mods - etc.
1). No I did not install the aftermarket radio. A shop did (Electronic express or cartonics if I recall correctly. They set my amp up to push my 12 shallow rockford at a 90% of the full 800w peak power).
I think its pushing somewhere near 50v on a 2 ohm 12" Rockford DVC in a sealed box. The lights kind of dim when the bass hits, but just barely. They also dim if I press on the door switch while driving.
2). I don't think so, the carfax and autocheck report came back clean before I purchased it. It did not show any flood damage. It was a clean title with 0 accidents on record.
3). Yes, its my first corvette. I am the second owner of the vehicle. When I got the car back in 2013 it had 50,004 miles. It now has 87,637 miles on it as of today.
4). What alternator do you recommend since I gave up my core when I bought a new one. Sadly I can't rebuild it now. How would I find out the exact valeo alternator that came with my vehicle so I can buy a replacement off of ebay with the right voltage regulator. I don't know if the ac delco valeo alternator that came off of a c6 has the right voltage regulator. Is there a way to tell without taking the alternator out?
Today:
I had my battery tested after just 3 months of use and apparently it went from 100% down to 73% so right now I have it hooked up to car charger to bring it back up to 100% again. Then I will definate do that voltage drop test and parasitic draw test.
As for mods installed in the car:
5). It has a l7 thump cam in it and a custom borla exhaust package on it with henson high flow cats installed. I couldn't get thru emissions until I installed the high flow cats. They wouldn't let the car pass thru without them installed.
Next up it has a dual cold air intake installed, my audio system, and it has those led headlights too. I think it has new pulleys installed to give it more acceleration, but I'm not sure.
As for the alternator that is currently installed it is a AC Delco valeo that came off a corvette C6 they had sitting out back with 45,000 miles on it.
The battery that is currently installed in the car to handle all of this is a walmart battery MAXX EVER START MAXX-75N 700 CCA 875
Should the valeo alternator and the battery I have be able to handle all of this?
Again the audio system is a pioneer 6800BS, kenwood K-9106D, Pioneer 6.5's with no amp on it AS or TS I believe its been years since they were installed so I don't remember which, and 1 rockford shallow DVC pushing 800w in a sealed box. They set the amp voltage right near 50 volts using a volt meter and an osciloscope for max bass output. I have no bass boost turned on either on the amp or in the headunit itself, I use pioneers premade powerful mode, and I use speaker levels at 7 front stage, 7 back stage,10 on the subwoofer. My HPF is set at 125hz with -12 octave. My subwoofer LF is set at 80hz. I crank up SLA to 4 or their is no hard hitting bass. The bass hits way harder with SLA kicked up to 4 when using my iphone. Without this turned on the bass is very poor in the car. I mean it feels like you are listening to just the radio and speakers. There is no hit. So I always turn SLA to 4. I don't know how much power it draws, but those are my settings if it helps.
I am fixing to do a voltage drop check once the battery charges all the way back up again. I will report the results after that. Thank you for all of the great info, while I am waiting can someone please show me pics of where the grounds are that I need to clean and check.
They did a test on my battery and it only had 73% with only 3 months of use.
Last edited by Mike's2001-Z06; Oct 8, 2020 at 06:40 PM.
One more quick question guys, when I am sitting inside the car looking for possible parasitic draws what should I really check to make absolutely sure nothing in the interior is able to drain my battery.
All Corvettes since the C4 have constant power draws - therefore they need to be started every 2-3 weeks if they are not on a ticker charger.
Any of the Chevy dealerships can give you the alternator requirements for your car.
Your stereo system may be a cause of some of your problems but it requires thorough testing by a auto shop.
There’s plenty of help on here - you just have to look for it by using the “search”.
So I did the battery charge and here is the result:
Charged battery to full and checked voltage immediately noticed the battery dropped from 13.99 to 13.98 and .1 ever 7 seconds when connected (Battery has date of 5/18 on it).
13.99 starting voltage with a
.1 loss every 7 seconds within 5-10 minutes it was down to 12.48 and thats just with the car sitting. I never even started it up.
Would this be a parasitic drain or is this a failing battery. Something on this car is killing my batteries and alternators. So far I have had 2 alternator swaps and 3 new batteries since I bought this car in 2013.
Last edited by Mike's2001-Z06; Oct 9, 2020 at 03:19 AM.
Even with the key off some modules are still “awake” and will need some time to go to sleep...wait about 10 minutes or so and see if the battery voltage continues to drop....you want to make sure your underhood light is off either by pulling the fuse or bulb...if battery is still draining this video may help..normal drain is about 20-30 milliamps !!
It's very important that you let all systems go to sleep before testing for parasitic drain and that you don't wake any of them by doing something dumb like opening the doors. So, take something and depress the door switches so the interior lights aren't on and you can leave the doors open so you can get to the fuses. Disconnect the engine light too as you hood will need to be up.
Also rebuilt alt for sale if you end up needing one (not mine)
When you say the battery was tested in post 11 above, was it load tested at the auto parts store after being full charged? If not, that should be done. After a full charge, does the battery lose voltage continuously while not connected? If so, it is bad.
Make sure that the battery cables are tight and cannot be moved on the battery after tightening. Some batteries have been found to have shallow terminal threaded holes. The bolt may be tight, but the cable is not tight against the battery.
If the battery load tests good and holds voltage while disconnected and then after reconnecting the battery the charging system generates 13 to 13.5 volts or more across the battery terminals when the engine is idling, the battery and charging system would seem unlikely to be the cause of the symptoms you cite. In that case, you really do need to do a battery drain test.
"Battery would drop while sitting idle at red light, car would eventually shut off after driving for 20 minutes or running idle for 20 minutes. I would have to keep on revving the engine while waiting at a red light or the car voltage would keep dropping and the car would die."
The above symptom could be a severe battery draw or a failing ignition switch.
"I can drive car somewhere close for 2-3 minutes. Go in grab something, goto start it up and their is no power inside whatsoever. No dash lights, no ding, no compressor or fan at all. When this happens I usually pull the key wait 2-3 minutes re-insert the key turn it and the car will start normally."
The above symptom sounds like a failing ignition switch.
"If I don't let the car run idle for about 3 or 4 minutes before driving off. The engine rpm winding down is much slower than normal until the car has been driven a few miles. Then it winds down normally."
Check for vacuum leaks as noted in post 7 above and close examination of all vacuum hoses.
If the battery and charging system are good and a battery drain is suspected, I would first pull both seat circuit breakers. Seat switches are a common cause of battery drain large enough to drain the battery overnight even with a maintainer connected. Ask me how I know.
So I checked my fuses using a multimeter in series with the negative power cable disconnected, then banana clipped the red multimeter lead to the negative ring terminal and the black lead to the black negative battery post. It had 3.4v drain, not one single fuse being pulled dropped the 3.4 reading to 0.000 on milliamps when I pulled them out 1 at a time for testing. I also took my 200A monster cable out fuse of the loop too to check if it was the audio system power wire. It stayed at 3.4 mA.
My hood was open and my car doors were closed. The car had been off since I got home from work with no doors opened at all. I let the car sit for an hour before I did any testing, the thing is my Z06 has never had a light under the hood since I bought it in 2013.
After letting the car sit for 1 hour once I got home I then began my test of all the fuses under the hood. The results were inconclusive.
The battery voltage when I began was 12.72v even while the multimeter was being used in series. As you mentioned I noticed an alternating voltage drop at first when I immediately checked the voltage after getting home. Once I let the car sit for an hour with the multimeter in series, but turned off the battery voltage stabilized at 12.72v. The battery voltage with the negative totally disconnected was 12.72 after testing.
After plugging the battery back up again, I then used the multimeter in DCV 20 to test the fuses as per your video. Not a single one under the hood showed a single voltage change. The meter remained at 0.000
When I tested it in series with the negative battery cable disconnected and the multimeter in series it showed a 3.4mA draw from somewhere.
So I noticed that when I plugged the battery back up after all of the testing the voltage climbed from 12.72 to 12.73 instead of going down as usual. All I did yesterday was charge the battery to full, then while I was waiting I changed my side post terminals on my battery to the extended bolts which really snug down the ring terminals way more than the old ones to allow me to easily do a big 3 upgrade if I need to. The pictures below show the swap.
This is the default terminals which seemed kind of shaky. This is what I swapped it with so I could easily add a big 3 upgrade if needed. The terminals bite much better and the really snug down the main battery cable rings on both sides since the additional bolt really allows you to lock it down tight.
Edit:
The bulb under the hood is missing, but I read somewhere this draws power constantly. Could this be the 3.4mA draw since it isn't even installed. It says its a 561 bulb so I will goto o'reillys tommorrow for one.
The car was asleep, I waited an hour before testing.I never opened the doors once, but the hood was up while I was looking for a 3.4mA draw. It turns out there is no bulb installed at the hood light, but the wire for the hood light is definately plugged up.
Last edited by Mike's2001-Z06; Oct 10, 2020 at 05:58 AM.
When you say the battery was tested in post 11 above, was it load tested at the auto parts store after being full charged? If not, that should be done. After a full charge, does the battery lose voltage continuously while not connected? If so, it is bad.
Make sure that the battery cables are tight and cannot be moved on the battery after tightening. Some batteries have been found to have shallow terminal threaded holes. The bolt may be tight, but the cable is not tight against the battery.
If the battery load tests good and holds voltage while disconnected and then after reconnecting the battery the charging system generates 13 to 13.5 volts or more across the battery terminals when the engine is idling, the battery and charging system would seem unlikely to be the cause of the symptoms you cite. In that case, you really do need to do a battery drain test.
"Battery would drop while sitting idle at red light, car would eventually shut off after driving for 20 minutes or running idle for 20 minutes. I would have to keep on revving the engine while waiting at a red light or the car voltage would keep dropping and the car would die."
The above symptom could be a severe battery draw or a failing ignition switch.
"I can drive car somewhere close for 2-3 minutes. Go in grab something, goto start it up and their is no power inside whatsoever. No dash lights, no ding, no compressor or fan at all. When this happens I usually pull the key wait 2-3 minutes re-insert the key turn it and the car will start normally."
The above symptom sounds like a failing ignition switch.
"If I don't let the car run idle for about 3 or 4 minutes before driving off. The engine rpm winding down is much slower than normal until the car has been driven a few miles. Then it winds down normally."
Check for vacuum leaks as noted in post 7 above and close examination of all vacuum hoses.
If the battery and charging system are good and a battery drain is suspected, I would first pull both seat circuit breakers. Seat switches are a common cause of battery drain large enough to drain the battery overnight even with a maintainer connected. Ask me how I know.
Second the load test. My battery was doing same as OP-Losing voltage steadily. Even though it still cranked the car over, had it load tested, and it failed. Bought Professional series AC/Delco battery, good ever since. A bad BCM can also drain battery overnight. I found out, the hard way, of course. I'm guessing you do have other issues, that assassinated your battery in the course of the 2 years it was installed.
Need help figuring out what is causing this
