Good buy on the Rio Grande! I have the same thing.
My oil pressure indicator was doing the same thing, I replaced the oil sending unit and it works fine now.
02-13-2011 01:37 PM
I just fixed this same issue on my 91 2.5L. Here is what I did.
Took the 6 screws out of the trim cover to remove it.
Took the 4 screws out of the gage cluster mouting bracket to remove it.
Removed the gage cluster by pulling straight out.
Unplug the gage cluster and bring it into a well lit location to inspect and clean.
Unscrew the nut that holds the oil pressure gage on.
Remove the lock washer with a very small screw dirver.
Pry off the black connector being careful not to damage the flexible circut board.
Clean all metal contact points and the pins that slide into the gage. Use alcohol a q tip and a pencil eraser for best results and to ensure that you do not damage anything. Clean the flexible circut board as well.
Pull the little screw back into its origional position and make sure it is very clean. It will be very difficult to screw the nut back on if you don't pull this back into place.
Put the cleaned connector, lock washer, and nut back on.
Repeat these steps for all of the gages while you have it out.
Before putting the cluster back in, do the same q tip and alcohol cleaning process to the main connector and it's connection pints on the flexible circut board.
Put it all back together and your gages should be working now.
This fixed my oil and gas gage. I hope it works for you. If not you may have another issue. This is very easy and took only a few minutes so try this first.
02-12-2011 06:57 PM
Where is the sending unit and how do I check this? Sounds like an easy fix to something that is bugging me.
01-04-2011 10:30 AM
Hello I have a Rio Grande too...and had the same problem...... sending unit !!
01-02-2011 07:15 PM
Thanks. You guys are great! I will try it tomorrow!
01-02-2011 06:59 PM
Turn the ignition on, pull the wire off the sending unit. The gage should go to one extream. then ground the wire and the gage should go to the other extream. If it does then that tells you the gage and wiring are good. Replace the sending unit. If the gage doesn't move then your looking at wire or gage problem.
01-02-2011 06:49 PM
A new sender ought to cure the problem.
01-02-2011 06:44 PM
Oil Pressure Gauge Pegged Out ? ?
I just purchased a 1995 Wrangler Rio Grande edition 2.5 L
All the gauges work EXCEPT the oil pressure gauge. It peggs out when you start the engine and stays that way all the time you are driving. When you shut off the engine it drops back down to zero.
How can the problem be diagnosed? Sender bad, gauge, or wire off or something.
Any ideas out there with you experienced guys? ? ?