Fuel & Rpm Guages Off Way Off .......

[TurboRussty]

hey guys what can i do to fix these things the fuel guage never marks correctly but it does move into different postions but it stays in the same positon without moving for a little while then when a start up the car again it will be in a different position....

the rpm guage light thingy well on my car it does not move and stays set at you can say 1100 rpms but it does not move whne you give it gas at all....

how can i fix this gm crap....

 

[scottyb]

I have similar problems. For the tach, check that the 2 connectors behind the alternator are NOT connected together. I think one is black and the other is green. One is for a tach and the other will run the fuel pump if you apply voltage. My tach did the same as yours for a few months, now it reads about double actual RPM's. If the wires behind the alternator are unplugged, then do a search on this forum. There is a guy that can put in new chips to make the tack work.

As for the fuel gauge, I'd bet it's a lazy sending unit. Mine dances all over, but not enough to bother me, and is correct when I get below 1/4. This is assuming you have the analog gauge.