I have a 93 Chevy Suburban that's got a problem in the dash. Basically when sitting at traffic lights I'm getting play in my guages. My tempature guage is fine and consistent. The problem is my fuel and oil pressure guage. Both usually sit consistant and normal. However they like to jump up about a quarter of a guage while setting at idle. They don't do it at the exact same time, but usually pretty close together, and they don't stick there just sit for a bit. Also my tachometer reads low at an idle (around 250-400 RPMs). I don't think it's likely to be the oil pump and fuel pump at the same time, plus I'm not getting any performance problems.

I've been told it could possibly be a bad ground, or electrical. I doubt also that two guages just went at the same time. It's not a huge deal. But with new vehicle prices I'd like to make this one last as long as possible. I appreciate any help, experince, or expertise on the matter. Also the vehicle is in excellent shape with 150,000 miles and alot of life left in her. I( just want to keep her in good shape and in working order. Again thanks for anything you have to put in.

Quoted: I've been told it could possibly be a bad ground, or electrical.

thats what it sounds like, could be a bad ground to the dash bezel

Quoted: Quoted: I've been told it could possibly be a bad ground, or electrical. thats what it sounds like, could be a bad ground to the dash bezel

My dodge truck was doing same thing to about 3 months agao and the mechanic told me it was exactly that, cost me about 100 dollars to fix because of the dash removal.

Could be a bad ground. However many vehicles use a small solid state voltage regulater behind the dash to provide a constant voltage to the guages, so they don't vary as the vehicles voltage does. Sounds like if yours has one it is acting screwy at lower voltage (idle).

Do they go read high when you have the switch on but engine off? Any change when you trun teh ehadlights on at idle and when the engines off.

Those engines were notorious for erratic oil pressure gauges.  There were many service bulletins regarding the issue.  I'm not sure if the erratic signals from the oil pressure sensor can effect your fuel gauge, but they are in the same circuit.

Here is the bulletin for the oil pressure gauge.


Number: 93-57-6A

Section: 6A

Date: NOV. 1993

Corporate Bulletin No.: 268304

ASE No.: A1, A8

Subject:
INCORRECT OR ERRATIC OIL PRESSURE READINGS

Model and Year:
1990-93 ALL LIGHT DUTY TRUCKS

Owners of some 1990 through 1993 light duty trucks may comment that the oil pressure dash gauge reads high, has intermittent erratic movement or is inoperative.

The internal resistance wire in the oil pressure sensor may not be properly supported, resulting in an intermittent open condition.

Service Procedure:

Check for normal causes of high oil pressure gauge readings (high resistance or open circuit), such as a poor ground path caused by loose sensor mounting, oil cooler adapter loose, or poor electrical connections. If no cause can be found, replace the oil pressure sensor following the procedure below.

1. Disconnect the negative battery cable.

2. Remove the wiring harness connector from the oil pressure sensor.

3. Remove the oil pressure sensor.

4. Install the new oil pressure sensor.

5. Connect the wiring harness connector to the oil pressure sensor.

6. connect the negative battery cable.

No. But when I checked it did'nt seem to be doing it. That's usually the way it goes, does'nt happen when you want it to. I started the engine, turned the key part way, and checked the lights and guages and no high jumping, and no change with the lights on. I also asked about voltage regulators thinking that might be it. I sure hope not I was told it was in my engine (Don't know if that's true or not).

Also keep in mind that on many GM vehicles the positive batter terminal (side terminal) can leak and corrode the cable.  Try cleaning up that connection, it is the source of many electrical Gremlins in GM cars.

GunLvr