Fuel & Temp Gauge max out when driving forward

[mattscar]

I have a 1992 with auto transmission and replaced the engine. Everything worked fine until I dropped a valve. Replaced valve and piston and all cylinders back to 150 psi. Engine works great but when I put it in gear and drive the temperature gauge and fuel gauge max out. Stopping at a light the gauges slowly drop back to normal. Can't find any missing grounds. Anybody have any ideas on this problem?

[geozukigti]

You might have a bad voltage regulator in your alternator. That's my best guess. Turn your headlights on, and rev the engine, and see if the lights get brighter when the RPM's go up.

[mattscar]

The lights stay the same. As r=this was happeneing, bought a reconditioned regulator and it still happened. Had it checked and was OK. Picked one up in junk yard and the same thing happens.

[dave_k672]

Mattscar, My fuel gage is doing the same thing. Did you ever figureout your problem?

[geozukigti]

Check the ground behind the center console under the dashboard.

[Phain]

I have a Samurai, not a Metro, although I'm planning on getting a Metro. I have done many mods and repairs to my Sammi. A thing that comes to mind in this thread is that we have a similar problem with run-away fuel and temp.

(background)
I have no idea if the wiring is similar. In the Sammi there is a voltage regulator (I think it is) in one of the gauges. The wiring diagram will show it as a coil around a core, just like the ones that control the needle movement. The needles move by the movement of a bi-metal element. The element is heated by a ni-chrome wire wrapped around it, the current rate determined by the sensor. The regulator is similar, except when it gets hot and bends, its bi-metal strip opens an electrical contact. The internal resistance of the ni-chrome wire knocks the voltage down that flows through the coil, and to the gauges.

(my idea)
In the Sammi, a wire frequently burns in two, coming from the regulator coil to the gauge coil. All current for both gauges is sourced through this coil. When the wire is burned, the gauges receive full 12v and peg-out, unless the fuel level is *really* low, and/or the engine is cold. It is easy to take the Sammi cluster apart and solder a wire back and fix it. Worth checking, anyway.

[WissNX01]

You could have a cross short. Providing the speedo is electronic, your fuel and temp gauges might be shorted into the speedo. This might cause wierd readings.

[bansheetaz]

did anyone have any fixes for this? i have a 95 thats doing this same thing.

[Woodie83]

Yes, geozukigti posted the fix above. The instrument cluster is not getting it's ground that it needs to operate properly.