atv_freak

My 02 Z28 has always had (bought it in May) an "active" voltmeter... though nothing I was really worried about (slight movement with blinkers).

Last weekend I got around to installing my sound system 500w Alpine amp powering a Kicker L5. I also bypassed the monsoon amp while still using the stock wiring (PO replaced the stock speakers with the wrong kind for the monsoon system). After I got it all installed and working, I tried starting the car... battery was dead. Long story short, got it tested and it was bad (drove the car to get it tested and don't remember noticing anything different with the voltmeter gauge). Noticed right away after the new battery was installed that the voltmeter was bouncing all over the place.

At idle it didn't move at all. With the lights on as soon as rpm's rose above 1k it would start bouncing (probably between 14-16 volts). As soon as the rpm's went back to idle it would calm down. With no lights on it stayed steady during normal driving until some sort of load was applied... be it brake lights, turn signals, hvac fan, etc. I had the alternator tested twice (two different places) and it passed both times. I went ahead and replaced it with a 145amp anyway and also replaced the exciter wire plug. The PO had done a terrible job with the exciter wire (twisted together and taped and the end of the wire stuck in the front end of the plug and then plugged in) and I thought for sure this was part of the problem! Got the lifetime warranty napa rebuild installed and wiring fixed... and same problem! It has changed a little bit... now sometimes when the rpm's return to idle the voltage will drop to 12-13 for a second and then pop back up. The lights noticeably dim during these drops.

I need to go through and check grounds. I've heard some mention that a bad pulley tensioner might cause something like this? I should probably remove the battery side post extender to see if that makes any difference.

Any ideas?

1 Slow WS6

iTrader: (1)

Do you have a capacitor for the amp?

atv_freak

I don't. It happens even if the amp is disconnected though.

atv_freak

Tried another Napa alternator... removed the battery post extender(which unhooked the amp)... no change.


http://vid11.photobucket.com/albums/..._173559697.mp4

How exactly do I check grounds?

atv_freak

Nobody has seen this problem before?

Firebirdmuscle

iTrader: (16)

I had an issue not to long ago where the stud on the back of the alt actually worked its way loose and my whole car went dead going down the highway at about 75 at about 1 oclock in the morning. and just incase you didn't know, lol, its pitch black dark then with no lights whatsoever. scariest thing that's happened to me yet.

anyway, I had no clue what was causing my voltage to jump like it was doing. it would do it, then it would it be smooth and show normal volts. not likely your problem but it would be worth to atleast look at it and make sure its tight. I had fooled that that stud in a long time and it slowly backed out a reckon.

atv_freak

Well I was hearing a little bit of noise from the belt tensioner so I decided to go ahead and replace it and the belt since a loose belt might cause something like this. I decided to try an ICT Billet manual tensioner. Didn't change anything!

I've redone all of the grounds that I could easily get to, but how in the world do you get to the grounds on the engine?!?

atv_freak

Well I replaced all the wiring coming off the battery as well as the engine ground strap (I guess Big 5 or 6)... no change! Where do I go from here?!?

Case2000

I would check any modified wiring in the whole car. I had my voltmeter bounce from 12 to 6 quickly every so often. Turned out the PO hacked up the turn signal wiring so every time i hit a bump it would short out and the voltage would drop for a second then come back.

HappySalesman

iTrader: (3)

Hmmm. Have you tested the voltage with an actual DMM? Or just using the gauge on the cluster?

atv_freak

I just have a cheap anolog meter, so it is hard to tell exactly where it is but I can see it bouncing the same way the gauge is. I figure the next thing to try is remove all the non running related fuses and see if that makes a difference. The PO did put in halo headlights and the halo's don't always work and there is no telling what other "wiring" they did.