All,

For about as long as I can recall I've noticed that the gauges in my 1988 Mitsu SPX 2.6l are a little 'funky'. For example, the volt gauge will occasionally read 14, the rest of the time it reads a hair over 12. My fuel gauge acts a bit sluggish, meaning I will start the car, it will read below half a tank for a minute or two and then swing up to where it should be. My oil pressure gauge starts out indicating low when the engine is cold(i.e., start and drive..gauge stays on or just barely past the 'lower' mark and goes up as the engine warms(?)) and my temp gauge, it is the one that bothers me the most. I have a 192 degree thermostat in the engine. On a cold start it will typically warm up to about 1/4 of the way on the gauge, and stay there for a while. Then after a bit more driving it will go up to halfway, and then swing up to 3/4 or higher and it usually refuse to come down from that point until I stop for a few minutes to run an errand. If I restart after letting it sit for just a few minutes the gauge will swing back down.

I've looked at the electrical diagram in the FSM, and I see the wiring for the gauges has some components in it, I see a capacitor and some diodes, among other things.

I guess my question is, has anyone had the flexible circuit board fail and cause the gauges to give erroneous readings? Even at 3/4 swing on the temp gauge when I think I'm about ready to just completely cook over, the A/C is still working. I tested the A/C cut out switch last night and while I wasn't able to make it open in boiling water, wanding it with a propane torch did cause it to open, so I know if it truly got too hot that the A/C should be turning off.

Any thoughts from the experts? Anyone put a mechanical gauge in to replace the electrical unit? I was going to go this route but it looked to me like the 'bulb' on the end of the capillary tubes for the mechanical gauges were too big to put into the stock sender location.

Chris

Check your grounds going to the cluster, you may have an issue there. Also, if there is a 'voltage stabilizer' wired in, see what voltage it's giving the gauges to work with. Some clusters don't get 12-14 volts from the altn, but instead, have a steady, lower, 'stabilized' voltage sent to them to prevent the problems you're seeing[erratic operation] I don't have any books for the earlier Gen 1 Monteros-so I can't help much

The only gauges on the regulated voltage are the fuel and water temp. The fsm has a warning about a failed ground at one of the screws on the back of the gauge pcb. If the ground fails, the gauge needle actuating bimetal strips see full battery voltage instead of the 7v they are supposed to see, and permanently warp, and thus read forever low. Pull the cluster and tighten all the screws in sight.

The oil pressure gauge behavior is puzzling. Cold start oil pressure should be quite high, as the oil is pretty stiff, and thins as it warms up, so the hot oil pressure is lower. I'd replace the sender and clean up/tighten the wiring connections, or even better, put in a mech oil pressure gauge.