Oil Pressure Gauge Needle

[John Maddox]

My Oil Pressure Gauge needle has started fluctuating rapidly - all appears well with the lubricating system. As senders are £60 any ideas before I try replacing anyone?
Thanks

 

[Mikie_gb]

My needle was pegged at the 5 marker. When I replaced the sender unit it went back to normal..... except for the same problem you are having. So I would suggest replacing the unit will not cure this. Some one else might have a suggestion.

 

[Fen]

I haven't had the problem but there isn't much to it; it's a sensor, a gauge and some wiring in between surely? That being the case it can only be a bad connection or a dodgy sender or gauge. I guess the thing to do is take the instruments out and see which contacts the oil pressure gauge uses then use a voltage meter to see if the voltage across them is all over the place (I suspect it will be). If you can get to the contacts on the sender while it's still connected then try the same there. Assuming that is bad too I guess the input voltage should be checked too in case that's what is unstable - presumably 1 pin is live with (probably) 5v?

Sorry if that's totally unhelpful but it's how I'd go about diagnosing it, never having actually done it before.

 

[Mikie_gb]

I had suspected that perhaps having the gauge pegged at 5 bars for over a year might have fuddled the workings of the gauge. I have had a rev gauge in another car throw fits, and that was down to a poor earth.

 

[John Maddox]

Thanks everyone.

This morning cleaned all the sender contacts - no change. Will get the multimeter out next and check for voltage fluctuations. All other instuements ok but will check the earth as well.