Welcome aboard!

The pressure sensors have a tendency to go bad after a while.
On my Van I had the same problem and a $20 oil pressure sensor proved to be the solution for it.

 

Thanks, Dirk. But, we already paid $140 for the new sending unit installed. The gauge in the cluster was not impressed. It still thinks the oil pressure isn't correct by bouncing all over. I guess I didn't express where we are now clearly. Is it possible, plausible, and maybe even likely to require the cluster to be rebuilt to fix a maybe(or real) faulty oil pressure gauge? I have not seen this situation posted anywhere in my efforts on the whole internet. I do not like driving a vehicle with the insecurity of proper oil pressure shown on the gauge. Think-volt gauge screwed up, gas gauge screwed up, tach screwed up, speedo screwed up. Major problem? I'll stop and show more concern for temp gauge reading high. No oil pressure = no engine. Please assure me, if possible, that the gauge in the cluster is or may be f'd up and I have to go the rebuild or junk yard route. I don't like parts changing unless it's required. Notice, I already forked over $140 and apparently this only bought me turning off the the check gauges light. Well, we see what comes up. Herman

 

The clusters have the tendency to give bad readings. temp and fuel gauge also. (GM fail???)
Your mechanic tested the oil pressure. so it was good???..
I would not worry very much. what is the mileage?
Even if it`s 25k i wouldn`t bother.
Someone else better clime in for your 2003.. I only do the old stuff :rofl: :rofl:
Maybe just a bad connection

 

If it's bouncing all over, either the gauge is bad or the ground is flaky. I'd pull out the cluster, clean and inspect all connections and wires (both on the cluster and the wires that plug into it), then reinstall to test. Oh, and follow the wires from the sending unit, too - a wire could be bad or chafing.

If that doesn't find the culprit, then maybe I'd look at a junkyard cluster.

 

Leeann, I like your logic. You're talking one step, logically, before a replacement. Do you think my mechanic would buy this? I'm reluctant to tear almost anything apart in this cash cow for mechanics. I'll do it, maybe, even though my mechanic stuff is limited to engines that I can see and change all spark plugs without resorting to Houdini's book of magic. I'm at best almost an OBD 1 sort of wrench turner. I'm bragging here as my first car in HS was a '31 Model A, graduating to a '49 Chev, big leap to '52 Merc, etc. These were stock, not Street Rods. HH

 

Sounds to me that your mechanic doesn't want to diagnose, that he just wants to be a parts thrower.

I think you can do this. Easier to start with the wires from the sender, so start there.

 

not sure of your exact symtoms, but my 01 has an oil gauge that bounces or "quivers" all over the place. I replaced my sending unit when the intake was off, hoping that was it. It's still bouncing.

 

Found this post while searching for input on oil prerssure sending unit...

At least I know I am not the only one to see flaky readings. Mine was bouncing
a bit then a few miles from home it went flat...oil level slightly high on dip stick and I know they
used 10w40 not 5w30 at oil change on Thursday. Temp level was fine and car was running fine
had just driven about 50 miles this morning no issues prior to returning home.

Stil looking for more detail... location of unit, avarage price of unit, etc.

 

Remove the wire from the sensor, the gage should read 80. Ground the sensor wire, the gage should read 0.

I would go for a ride with the wire off the sensor, and then again with the wire grounded, and see if the gage acts up. If it does, then there is the possibility of wiring problems, or the gage is toast. Remove the I/P and check/clean any connections that look less than pristine. Then try the above again. The gage can be replaced at the proper maintenance facility, but it would be easier and cheaper for you to get an I/P from the JY.

There is a special tester for checking the gage. (Probably at the Stealership) It hooks up to the connection at the sender, and "loads" the circuit with a variable resistance, the tech then looks at the gage to see if it reacts to the tester setting. I am unaware of any mom&pops that would have such a piece of gear. Most mechanics, including myself would have done exactly what your guy did. 99% of the time it is the sender.

Bob

 

Junwa,

Location
Oughta be on the rear of the engine and visible when the doghouse is removed. Just right of the left/drivers side valve cover.

Testing
1. Check the oil level and correct as necessary. Turn the ignition switch on, but do not start the engine.
2. Disconnect the sensor lead at the sensor. The gauge should read full scale.
3. Ground the connector. The gauge should read at the bottom of the scale.
4. At 0 psi the resistance of the sensor should be 1 ohm.
5. At 40 psi the resistance of the sensor should be 44 ohms.

Hope it helps, Jim

 

Thanks for details, I replaced mine yesterday and all is right in my guage cluster once again... thanks!!!

 

Thanks for the update Jun

Jim

 

...Stil looking for more detail... location of unit, avarage price of unit, etc.

On 2000 Astro LS with 4L Vortec engine its just below the distributer. That means you have to take off the dog house. There is a special Socket that you can buy or borrow to make it easier to remove.

http://www.carparts.com/details/Che...et/Astro/Replacement/Oil_Pressure_Switch/2000/LS/6_Cyl_4-dot-3L/REPC311404.html