Oil pressure guage

Not sure where to post this.My guage is going crazy on me.Sometimes it works right and then it goes way past the 90 psi.Are the guages on an 82 electrical or do they have a tube going to a senser or an oil connection.Is this very hadr to fix.Thanks.

Thanks.pumps.Where is it grounded?I suppose under the dash!

Just Lurking. I have an 82 and the guage hardly comes off zero. Scarey, but temporary mechanical guage shows ok pressure. Don't know where to look at the moment.

Actually I put my keyboard in motion before I put the mind in gear. The gauge is wired as follows on a '79. There is a power wire coming from the fuse panel going to the center cluster that powers all the gauges. The ground part comes in from the sender. The whole center gauge cluster has a printed circuit board to distribute power and ground. When I changed my radio from stock to a din type I recall having to take care when putting the cluster back in. As the oil pressure rises and lowers, it varies the electrical ground potential to the gauge via it's connection to the block where it is grounded. So this puts a lot of possibilites in it. Sender, circuit board, gauge, could be any one of these. I think the first thing I would try is the sender, cause it's the simple to get at and change. Then from there you may have to pull out the center cluster, check the connection from the harness, the circuit board for any breaks or suspect the gauge itself. Sorry for the quick answer before, but I think the sender may be the fly in the ointment.

Dave 

Granted, there are many possibilities in old cars.  But Chevrolet did have a problem with oil pressure sending units.

Thanks guys.I'll check the sender first.