Sorry this is a bit long. In my console I have Autometer fuel and volt gauges (the other two are mechanical H20 and oil psi). Today I dropped in the 5" tach and speedo.
The tach and speedo work perfectly, as do the turn indicator LEDs and high beam light. The problem is the volt meter. It's either dead or goes crazy at random. The fuel gauge is wired but not connected in anticipation of the fuel cell going in tomorrow. All connections for it are taped off. Here is how I ran all of it.
Tach, volt, and fuel gauge share power from the the ignition terminal on the fuse panel. The volt and fuel hot leads (+12V switched) share a wire that splits off under the console. The tach has it's own wire with a 4amp in-line fuse but, like i said, is sharing the ignition spade with the other leads.
Volt and fuel are grounded to the block through a common wire. Tach is also grounded to the block through it's own wire. Both grounds are connected to the bolt that holds the firewall to block ground strap. They are connected at the firewall side.
All connecters are covered with electrical tape to prevent shorts. The plug with all the old warning light leads is taped off.
I don't think it's a ground problem since the tach works fine and shares a ground with the other two. Do I need to separate one of the power leads? Could I maybe run the voltmeter off the power feed (pink wire) that went to the circuit film? What in the hell did I do wrong?
Keep in mind that the tach is reading a pulsating AC signal where the other guages are reading DC. Not that it explains your problem, but grounds could still be an issue even though the tach seems to rule it out.
68 Coupe, 350 w/ Edelbrock Performer RPM heads, cam, intake, 700R4, Dave's small body HEI
Turned out to be something really stupid. The power lead for the console gauges was half pulled out of the crimp. I must have bumped it while installing the speedo cable. I love how it was the last thing I checked. Everything works perfectly now.
Spongebob, sounds like you found the culprit. Which style autometer did you end up going with? I am currently missing the summer in the states right now (am in Uzbekistan-former USSR) for another 40 days. Missing all the summer cruise/shows. Not too many fast vehicles over here, kind of hard when speed limit is 5 MPH in tent city . Good luck!
1968 Camaro SS coupe, Lemans Blue/medium blue interior
LS3/T56 Ridetech Suspension
Yep, got it pinned down. Thanks for popping in. I went with the Phantom series. The white looks great against the blue interior. I also used blue bulbs in all the gauges which looks sweet at night (you and I have the same paint/interior colors). It probably sounds a little ricey but it doesn't look it.
Bummer about being overseas. At least it's Uzbekistan and not Iraq. Friend of our family is an MP currently stuck in Baghdad. Was supposed to be home by now but was told he had to stay for awhile longer. We just keep our fingers crossed that he makes it home in one piece. Seems like we've been losing a couple every day or so lately.
Anyway, I'm sliding off topic here. Thanks for serving! I know the majority of us appreciate it.