Hi,

I am overhauling my sons 69 camaro while he is deployed to Afghanistan. He has an aftermaket console with gauges. console looks brand new, but gauges were never hooked up. prior to going out and buying wiring harness to make it work, I tried to see if gauges were operational:

amp gauge - not interested. Volt alternate too expensive. he can live without.

fuel and temp. tried simple op checks and they work - kinda. grounding out the senser max'd out the gauge, but they do not seem to have a spring pulling them back to zero. are these gauges bad? (hooked up power and ground, then grounded input, worked fine...but needle did not want to return, only gravity pulled either gauge back.

is that normal? or...I assume these expensive gauges are broke

thanks for any advice.

 

Are you saying they glide back down to zero, just not snapping back in an instant? That would be considered normal. But, if they aren't going all the way down on their own, they're bad.

 

Is the temp guage mechanical or electrical? The fuel guage will stay where it is at until hooked to a power source to tell it to come down. The fuel sending unit is a rheostat that sends power to the guage so where it is unhooked is where it will stay. If you maxed out power it will be full. Same with temp if it is electrical. Mechanical should go back to ambient temp.

 

Not so, the sending unit sends degrees of ground (based on the rheostat position), not power to the gauge. With power to the gauge, then grounding the gauge wire (usually a tan wire) at the sending unit, will peg the gauge to empty. Disconnecting that gauge wire at the sending unit should make the gauge read full. Switched power gets run to one side of the gauge, and the sending unit (ground) to the other side. With the ignition switch off, power to the gauge is killed, and the gauge relaxes (or should) back down to zero.

 

FYI on this. the fuel gauge in this camaro's console does not follow the principal above. pos (obvious) ground (max's out gauge to full) then sending unit controls gauge back towards empty. (whacky!) took me some time to figure it out, and with only three wires, embarrassing! 'assume' this is stock configuration as I just replaced the fuel tank & sending unit with aftermarket stock. with this car, my only issue is it's not 100% accurate, when it gets to "E" it still has 4/5 gallons, no biggy, but it makes the gas gauge go a bit faster alluding to even worse gas mileage. (not that a 454 can ever brag about mileage – I have yet to see a muscle car owner who doesn’t rap the pipes for the crowd at every intersection) now, need to figure out how to adjust the fuel gauge a tad without breaking it. building this damn thing on a budget and not playing musical guages. (car is for my son deployed in Afghanistan)

temp gauge: brand new but no-workie. leery of just buying another, might be some crazy sending unit issue. (for you purists out there, stop reading here...I just trimmed the plastic holder in the console and jammed a 19.95 white face gauge for temp gauge and same for voltmeter vice AMP. (like many, I was glad to see amp meters go away) but they all work, and hard to spot the difference when jammed under the cover of the console (for the non-muscle car purists)

anyway, thought the fuel gauge operation was interesting.

 

Are there only three wire hookups to the back of the volt gauge?
1. hot lead
2. ground from sending unit
3. lights

 

The way I worded it earlier may have mis-lead you about the gas gauge hookup (I'm gonna edit it). When the wire at the sending unit (from the gauge) is grounded to the body, it should peg the needle to empty. Just disconnecting that wire should peg the needle to full. Something's still goofy if the gauge isn't accurate though. Does the separate ground wire on the sending unit have a good connection?

 

yes, for my setup. just a standard sunpro voltmeter with pos/neg/light. white face/needle, no way does it match - but it all looks close as a glance, main issue being that you can see part of the chome ring of the gauge. but...since i wasn't afraid to grind plastic, I had it in - in about 10 minutes. I was able to ditch all the underdash aftermarket gauges the boy had.

as for the fuel tank/sending unit (in my personal "and quite often wrong" opinion) this is the area many/most ignore. they just slap a big filter and call it good. most these old tanks are crap, it's just not that expensive to change it out for 200.00 and not worry about old varnish or your favorite phrase for what happens to old fuel. being military myself with 13 deployments, i've seen gas go bad sitting less than a year. and you know most of these cars sit for extended periods. I normall restore drag boats, not cars and its even worse in them.

I would post pictures, but no idea how on this website, keeps kicking my *** - and I just don't have computer patience when it comes to that stuff.

 

"Does the separate ground wire on the sending unit have a good connection?"

wow, missed that. might be. i'd bet money you are right - i hooked it up, so you know how that goes. "half your maintenance is from half your maintenance"

thanks - that's a friggin awesome guess.