Gauge issue "stock"

[mrgrim]

My oil pressure gauge is at max and wont move. My temp is at min reading and wont move. Other gauges work fine. I took the cluster out to change the bulbs and make sure every thing was connected. I did not see any thing strange but it was the first time I ever looked at one. Im not sure if there is a sender on the motor for these that fail or if its some thing in the gauge its self. Any one know about these gauges that might point me in the correct direction?

 

[British Slave]

General Motors 0-90 Ohm Gauge Diagnosis Procedure​

Especially as cars age, it is often somewhat difficult to pinpoint the root cause of instrument cluster gauge failure, thanks to questionable wiring, normal wear and tear, and sometimes even incorrect diagnosis procedures. The following diagnosis procedure is the method that GM publishes in it's shop manuals, will work on oil pressure, temperature, and fuel gauges, and should apply to all but the most recent GM-made vehicles with computerized gauges.
Before You Begin
You will need either Kent-Moore tool J-24538-A, if available, or tool JG-GM-1, a homemade GM gauge testing jumper. To build tool JG-GM-1, you will need the following materials:

• 1 Jumper wire with alligator clips (about $2 US from Wal-Mart)
• 1 220 ohm, 1/2W resistor (Radio Shack #271-1109, pack of 5, $0.99)
• 1 150 ohm, 1/2W resistor (Radio Shack #271-1111, pack of 5, $0.99)
• about 1" of 1/4" heat-shrink tubing, or vinyl electrical tape

Construct the jumper as follows:

1. Cut the jumper wire in half, and strip about 1/8" of the insulation off of the cut end of each wire. Tin the bare wires using a soldering iron.
2. Take both resistors and twist their leads together on each end, so that the resistors are joined in parallel. Twist the leads tightly, cut off the excess, and tin the twisted leads. If using heat-shrink tubing, make sure that the resistor assembly is about half the length of the tubing, or less.
3. If using heat-shrink tubing, slip the tubing over one of the jumper wire halves.
4. Solder each half of the jumper wire onto the opposite ends of the resistor assembly.
5. If using heat-shrink tubing, slide the tubing over the resistors and solder joints and shrink using a low-temperature flame or hair dryer. If using electrical tape, tightly wrap the tape around the resistors and solder joints, ensuring that the solder joints are completely covered.

Diagnosis Procedure

1. Disconnect wire from sending unit, and connect tool JG-GM-1 from the wire connector to ground.
2. Turn ignition ON.
3. If the gauge being tested reads at the high end of the scale (i.e. full for gas, 60psi for oil, etc.), the sending unit is at fault and must be replaced. Retest after sending unit replacement.
   Else, go to step 4.
4. If the gauge responds, but not accurately, go to step 5.
   If the gauge does not respond at all, go to step 7.
5. Disconnect engine harness connector at firewall bulkhead. Connect tool JG-GM-1 from ground to bulkhead connector lead that goes to gauge. If the gauge now responds accurately, check the wiring between the sending unit connector and the engine harness connector, repair any faults, and retest.
   Else, reconnect the engine harness connector, and go to step 6.
6. Remove the gauge from the instrument cluster and check the speed nuts holding the ceramic shunt across two terminals on the back. If they are loose, tighten them and retest gauge; if tight, the gauge is at fault and must be repaired or replaced.
   NOTE:You might be able to repair the gauge with a kit from Fix-A-Gauge, and/or you might be able to manually reposition the needle where applicable. Retest after repair.
7. Remove the instrument cluster and check for bad connections at the gauge terminal clips, instrument cluster connector, and both the instrument cluster and sending unit ground. If the connections are good, inspect the wiring from instrument panel to firewall harness connector, and repair any faults if found; if bad, repair the connections, reinstall gauge, and retest. If the connections and wiring are both good, the gauge is at fault and must be replaced.
   NOTE:A gauge diagnosed as bad through this step most likely can not be repaired.

 

[maxgforce]

what year and engine?

 

[mrgrim]

88 Jimmy 350 TBI

 

[maxgforce]

Oil pressue sender is either protruding next to the distributor or on the driver's rear of the block above the filter, if it's stock it will be electronic with one wire connected to it. For the gauge to stay max'd out it has to have a neg. short somewhere, either in the sender or the wire between the gauge and sender. I would unhook the sender and see if the gauge still max's out, if it does then you probably have a short in the wiring, if unhooking the sender prevents the gauge from moving then i'm sure you have a bad sender.
The temp. sender is right between number 1 and 3 sparkplugs, again with one wire going to it, if your thermostat is working correctly them I think you have a bad sender there.

 

[slaveinc]

I have the same exact issue on my 91 sub. I disconnected the plug and it is still maxed out.