Author Topic: Gauges go dead after driving (Read 525 times)

Dne' · « **on:** August, 14, 2011, 06:42:52 AM »

I guess something had to go wrong sooner or later, but I'll start my stang, all the gauges read the way they're supposed to, then after about 10 minutes or so, all the gauges creep down to nothing. I had installed an electronic contant voltage regulator before putting my instrument panel in; never had a problem until recenty. Sometimes I'm lucky and the gauges don't go dead, but most the time do. Like the fuel gauge goes empty, not towards the full. Is this a faulty constant voltage reg? The voltage output from my 100 amp Tuff Stuff alternator puts on 14-15 volts on my under the dash voltmeter. Would I have too much voltage from my alt?
dne' ; )
photo is a couple years old~

Midlife · « **Reply #1 on:** August, 14, 2011, 11:04:25 AM »

Sounds like the output of the CVR went kaput to me...

Dne' · « **Reply #2 on:** August, 14, 2011, 12:31:48 PM »

Hi Midlife! Things I have to do so say HI! Darn thing didn't last very long! oh well! Here I go to start looking for another one.
thanks,
; )

blue65coupe · « **Reply #3 on:** August, 15, 2011, 10:40:00 AM »

Not an electrical expert but could there be a grounding issue?

Midlife · « **Reply #4 on:** August, 15, 2011, 02:12:44 PM »

Quote from: blue65coupe on August, 15, 2011, 10:40:00 AM

Not an electrical expert but could there be a grounding issue?

At the CVR, perhaps, but if voltage out from the CVR is good, the ground for the gauges are actually at each of the sending units. All three sending unit grounds would have to be bad.

Mach1Rider · « **Reply #5 on:** August, 24, 2011, 08:28:53 AM »

Quote from: Midlife on August, 14, 2011, 11:04:25 AM

Sounds like the output of the CVR went kaput to me...

I agree, the 14-15v while running may have cooked or overheats the CVR.
It may be using an old style CVR may keep this from happening.

Dne' · « **Reply #6 on:** August, 24, 2011, 09:04:07 AM »

I had installed a new electronic CVR. I do have the old one around here somewhere. I'm kind of worried about the alternator putting out too many volts (alt with external VR), but the volt meter in the car doesn't exceed 15 volts upon startup, then settles back down to 14 when running.

Quote from: Mach1Rider on August, 24, 2011, 08:28:53 AM

I agree, the 14-15v while running may have cooked or overheats the CVR.
It may be using an old style CVR may keep this from happening.

Mach1Rider · « **Reply #7 on:** August, 25, 2011, 10:06:35 AM »

Quote from: blue65coupe on August, 15, 2011, 10:40:00 AM

Not an electrical expert but could there be a grounding issue?

Yes, Missing,loose,poor body grounds are the leading cause of electrical problems.
They are very important, Just take one look in a new cars engine bay and see just how
many they have in place to insure all the sensors work properly.

apollard · « **Reply #8 on:** August, 25, 2011, 11:17:14 AM »

14 volts when running is fine. Modern cars typically run at 13.8-14.4 volts, and batteries like that much better. All auto electical components should be able to handle that. Remember that a fully charged "12 volt" battery is really 13.6 volts, so you are running just above that.

I think you have a bad ground or overheating CVR. When electronic voltage regulator components overheat, they are designed to reduce voltage output, and eventually shut off to protect themselves - and reset when they cool off. Exactly the behaviour you are seeing, so I think it is overheating. Pretty common with the cheaper electronic voltage regulators IME.

Dne' · « **Reply #9 on:** August, 25, 2011, 01:38:49 PM »

Soooo, you think maybe putting in a non electronic may be the way to go? I haven't ordered anything yet. I agree with you on it must be overheating as when I let the car rest for 20-30 minutes, it's starts working again! Plus when I have it apart, I'll double check on the ground again. this wouldn't be something to keep me from driving the car? I wouldn't want a fire under my dash! thanks!!
dne'

Quote from: apollard on August, 25, 2011, 11:17:14 AM

14 volts when running is fine. Modern cars typically run at 13.8-14.4 volts, and batteries like that much better. All auto electical components should be able to handle that. Remember that a fully charged "12 volt" battery is really 13.6 volts, so you are running just above that.

I think you have a bad ground or overheating CVR. When electronic voltage regulator components overheat, they are designed to reduce voltage output, and eventually shut off to protect themselves - and reset when they cool off. Exactly the behaviour you are seeing, so I think it is overheating. Pretty common with the cheaper electronic voltage regulators IME.

apollard · « **Reply #10 on:** August, 26, 2011, 07:20:17 AM »

Quote from: Dne' on August, 25, 2011, 01:38:49 PM

Soooo, you think maybe putting in a non electronic may be the way to go? I haven't ordered anything yet. I agree with you on it must be overheating as when I let the car rest for 20-30 minutes, it's starts working again! Plus when I have it apart, I'll double check on the ground again. this wouldn't be something to keep me from driving the car? I wouldn't want a fire under my dash! thanks!!
dne'

Doubt it would cause a fire, they are pretty good at protecting themselves. If it did go, it would just let the smoke out and quit working (all electronics really work on smoke, when it gets out, the part stops working

).

Knowing something about voltage regulators, a good quality electronic one will not be cheap. I'd put the original back in, or a mechanical replacement. Nothing wrong with them for the application IMO. Our guages don't need ripple free stabilized voltages, just something approximating 5-6 volts. Heck, our guages are pretty much indicators anyway, not exact instruments.