Having somewhat of a problem...

**Lone Lobo** · 11-15-2006, 05:04 AM

Okay, 1998 Z28, with the LS1 and everything. A while ago, like, two winters ago, the alternator died. So, we lifted the car, took it out, replaced it (not the easiest task, getting that alternator out and in, lemme tell you), and drove the car again in the spring. Problem is, that you can't rev it over about 4200 RPM without "Check Gauges" coming on. But we ignored the problem, as we were excited, so we put the hammer down among other things. The alternator died the same night we put it in (voltage gauge went straight down). So we had it replaced, and then whenever it was revved to about 4200 or over, check gauges, and if you kept doing it, gauges went jumpy and stuff. And then the gauges went jumpy, without revving it (read on here that's the alternator throwing a lot of interference into the electrical system?), and that alternator died. So we took it back (like the first one), replaced it, except he tested this alternator, it put out very small voltages at like, 1 amp. The new one he gave us tested normal. So we had that one put in. Now, still having the same rev problem, no jumpy gauges, at all, but the voltage dips (I don't remember if that happened before this time), and what I mean by dips, is that at low RPMs (like, stopped or on the highway), the voltage gauge will dip down to 13, then go up to 13.5/14, and it can do that a few times.

So, three alternator replacements, the battery has been replaced twice before (not after the alternator problems, however, could the battery be the problem? Like not holding a charge?)

Any ideas?

**SPECOPS94** · 11-15-2006, 06:14 AM

Have you checked for a grounded/grounding O2 sensor? They cause the CEL to come on and if it is shorting it will cause the drain and possible the jumpy guages you've experienced due to current grounding.... A thought.... Also, make sure that there are no frays or exposed wire from the ALT...Re-check all ALT connections and anything that was removed previously..
Mike

**Lone Lobo** · 11-15-2006, 07:43 AM

Originally Posted by SPECOPS94

Have you checked for a grounded/grounding O2 sensor? They cause the CEL to come on and if it is shorting it will cause the drain and possible the jumpy guages you've experienced due to current grounding.... A thought.... Also, make sure that there are no frays or exposed wire from the ALT...Re-check all ALT connections and anything that was removed previously..
Mike

Will check the O2 sensor soon. Have checked the wires and had them checked by someone for like, $400, no problem there. Thanks.

Also, the only time the voltage dips is when the engine is physically running, without it running, it doesn't happen.

**Steve Crowe** · 11-15-2006, 11:06 AM

Make certain you've got good grounds going from the engine block both to the frame and to the battery negative terminal.

**Hi-Po** · 11-15-2006, 11:06 PM

13.5 to 14.0? no way you can read that small of a differenence on the guage. Everything sounds fine to me. The voltage regulator controls output between 13.5 and 14.5. When it goes HIGHER than battery's and computer parts start damaging. Sounds to me your car is A-O-K.

**Lone Lobo** · 11-16-2006, 03:57 PM

Originally Posted by Hi-Po

13.5 to 14.0? no way you can read that small of a differenence on the guage. Everything sounds fine to me. The voltage regulator controls output between 13.5 and 14.5. When it goes HIGHER than battery's and computer parts start damaging. Sounds to me your car is A-O-K.

No, the voltage drops to 13, from where ever the regular number is (I was guessing 13.5 or 14).
It sometimes goes lower than 13, not often, though. But when the voltage drops, both exterior lights (headlights), and interior lights drop in output.

Edit - As well, it's not the Check Engine light, remember, it's the Check Gauges light that flashes on.

**98Camarod** · 11-20-2006, 08:41 AM

Im assuming that you checked the ground that comes off of the alternator?

**Sarge** · 11-20-2006, 09:22 AM

Do you have any aftermarket security systems?

**bigrondownhiller** · 11-20-2006, 01:47 PM

im not sure of the newer cars but older, 80's-early 90's gm's, sometimes the starter would drain power if it was bad. i had an 80's camaro that was draining all the time and found that the starter was bad.

**Lone Lobo** · 11-23-2006, 08:49 AM

Originally Posted by 98Camarod

Im assuming that you checked the ground that comes off of the alternator?

Yes

Originally Posted by Sarge

Do you have any aftermarket security systems?

No, just the one from the factory.

Originally Posted by bigrondownhiller

im not sure of the newer cars but older, 80's-early 90's gm's, sometimes the starter would drain power if it was bad. i had an 80's camaro that was draining all the time and found that the starter was bad.

I have to doubt it, otherwise it would be draining all the time while driving, with the current problem, it's only sometimes.