1986 Gauges

[greyhound]

I just got my instrument cluster back from being repaired. (Batee does a great job by the way)It looks great. My question is. the gas gauge allway shows full. The estimated range fluctuate from 670 miles and to 447 miles. The average gas mileage works ok most of the time . it shows around 22 most of the time but sometime drops to 5. Temperature gauge seem fine and alternate works ok . Oil temperate reading is good and the Pressure was good at 12 psi idle and 40 driving. Now it has gone to 0 driving and sometimes will show 1 or 2 at idle. The oil was just change and drove it 300 miles yesterday so I am sure The pressure is good. Not sure if I am chasing a loose ground wire and where to look or if this information is coming from the ECM. Any thought or help would certainly be appreciate

 

[hcbph]

Being no one has responded, as I understand it the ground is on the drivers side kick-panel, under the carpet on the side just below the dash.
That's on my list of things to do on my 86 (clean them up) so best I can provide.
I'm assuming there's some way to run a temp jumper from the instrument cluster to the ground of the battery so theoretically you should be able to confirm if it's a bad ground or not that way.

Sorry, not an electronics expert but best guess on my part.

 

[greyhound]

Being no one has responded, as I understand it the ground is on the drivers side kick-panel, under the carpet on the side just below the dash.
That's on my list of things to do on my 86 (clean them up) so best I can provide.
I'm assuming there's some way to run a temp jumper from the instrument cluster to the ground of the battery so theoretically you should be able to confirm if it's a bad ground or not that way.

Sorry, not an electronics expert but best guess on my part.

That more than what I had so, its a start. I just replaced the weatherstipping . It was as wet inside the car as it was out side when it rained. This would make perfect sense for the ground to be bad if it sat under wet carpet. I will peel back the carpet and see if I can find it. Thanks for you input