I'm trying to track down why my Temp guage reads too high. It's usually reading about 3/4 to the right, say around 220? But yesterday I took my '71 to a Z mechanic for some fine tuning, and we proved that it's actually running around 180, by using a thermometer. Over the last 3 months, I've replaced the Temp Sending Unit, Radiator, Rad Cap, Thermostat, and hoses. And yesterday we tweaked the Valves, Timing, and Carbs. It's running great! But it's hard to just ignore the Temp guage. Is there such a thing as a Dash Voltage Regulator? I know my Roadster has such a creature, but I can't remember which guages it controls. Also, the mechanic thought that the top half of the guage, the Oil Pressure, was reading too high also. I know that the Z guages aren't accurate, but I'd like to at least try to fix it. Thanks...Robert

Since the meter is reading series resistance to ground you could just put in an adjustable resistor in line and adjust it so the meter reads where you want it. Then measure the value that you have set and replace it with a fixed value. If it is a case of too much resistance causing the high reading put the resistor in parallel with the sending unit (from the sending wire to ground) and adjust it the same way.

how about running a separate ground right from gauge to chassis or battery terminal as a test? if the gauge reads more realistically with a known good connection, it would indicate either a contact/corrosion problem or just a poor wiring harness ground. at least it would give you more info to work with.

For hints on the dash voltage regulator repair, see the following:

http://www.jrdemers.com/280ZX/regulator/regulator.html

For hints on the dash voltage regulator repair, see the following:

http://www.jrdemers.com/280ZX/regulator/regulator.html

That article is about 280ZX, does a 71 240Z have one, I wonder?

Too bad Dr. Joe didn't/hasn't yet gotten back to completing the article.

Dr. Joe, as you call him, sure has alot of good info on his site, quite the resource, but then I do own an '83 in addition to my '71. Thanks for the link.

mlc240z - I'll try that gound idea, thanks.

I think long term I'm going to replace some of the guages, but I haven't done any searching yet to see what others are using.

TGIF...Robert