gas gauge ???????

[Big John 85]

The gas gauge on my 85 salon is not working (reads empty). I pulled the gauge cluster out and have no idea where to start. Are there any wires under the hood for the gas gauge? The guy before me was a HACK and there are tons of wires not plugged in. I have thought about getting a after-market gauge but I would like to use the factory one if possible. I don't want to pull drop the tank yet as this is the only car I have at the moment.

[Joeypete]

I think more often than not it's the fuel sending unit which is located in the gas tank unfortunately. I have a similar problem with my Custom Cruiser...though it works, just doesn't fall below 1/4 tank. But since you said there are a lot of loose wires it could be that. Do you have a shop manual?

[Big John 85]

My first thought was the sending unit but the rest of the gauges don't work either. I know the problem with the others thou (censers are missing). I don't have a manual but have been thinking of getting one. When I pulled out the cluster I got stumped looking at the plug for the cluster. What wires are what?

[Lady72nRob71]

This may help you ID the wiring (solid pink is the gas gauge wire):
http://www.442.com/oldsfaq/ofmsc.htm...bodyConversion

Also, the reliability of the gauges can be improved by going through these steps:
http://tlentz.oldsgmail.com/howto.html#gauge
http://tlentz.oldsgmail.com/howto.html#tach

Hope this helps...

[Big John 85]

I pulled the cluster out and found the pink wire but how do I go about checking it. I have a volt meter but don't know what setting to use. Is there a way to check the gauge outside the car without the sending unit and can I find out if there are any ohms going though the wire?

[Big John 85]

Now after I put the cluster back in the gas gauge reads full! WTF! I drove around all morning and it didn't move so it's still not working.

[Lady72nRob71]

Something is not right about that (or you have a full tank and get good mileage!)
Disconnect the connector that has the pink wire in it.
Use the low Ohms scale and measure from the pink wire to a good ground.
Report back what you get.
I am thinking it should be between 10 and 90 Ohms. I will have to consult the service manual when i get home to be sure...

[Big John 85]

Hopefully I did it right. I got 12.30. I am prity sure it has atleast a half tank of gas. If it reads that low shouldn't the gauge read almost empty. It's still on full. Should I get gas and then check it again?

[Lady72nRob71]

According to the FSM, 0 Ohm is empty, 90 Ohms is full.
12.5 Ohm would be 1/4 tank or so.

Make sure the black ground wire is in that cluster connector position #2. Ohm this wire to ground and you should have close to 0 ohms, indicating a good ground.

Gas gage wire is on position #3

12V pink / black wire is on #10. Since, you gauge moved to full, the 12V I think is present... MEasure DC volts to measure from there to ground with the ignition on.

If these 3 all are not making contact, your gas gage will malfunction.
Of course, if either of the 12V and ground are missing, the rest of your gauges will not work, either.

If you get 5 gallons of gas, you should hit about 40 Ohms or so and should prove the sender okay. Do not fill it all the way until you get the problem fixed.

[Big John 85]

I checked all of the wires. there all there I was on the wrong wire cluster. The wire in slot #3 reads .08. The pink-black reads around 12DC. and the black reads 0.

[Big John 85]

If the wire in slot three reads .08 does that mean the sending unit is junk or maybe not getting a signal through.

[Big John 85]

I don't know what I did wrong but I put the cluster back in and now nothing works. The cluster is totally dead. The turn signals work but don't flash on the cluster. The high beams work but the light doesn't come on on the cluster. I checked fuses and they looked good. The tack even stopped working.

[Big John 85]

I got everything working again. The gas gauge went down to 1/4 and on the way to the gas station it slowly went to full. I was only ably to put 4 1/2 gallons in so I'm going to try running it down more next time. The car sat for 3+ years I wonder if the sending unit is just stuck.

[Lady72nRob71]

It sounds like the popular "erratic gauges" syndrome... Unplug the connectors and get a good pencil eraser to polish up the contacts on both the cluster and the connector. A wire brush on a dremel will work good on the connector contacts, but do not use that on the cluster.

You want to totally rule out the cluster connections before you go changing the sending unit in the tank.

The tach jumper may also need soldering if it jumps around.

What else was hacked up on this poor car? If there are any non-factory crimp joints or wire nuts involved, they will need to be replaced with soldered connections and heat shrink tubing.
Exposed copper will oxidize and cause intermittant connections.

[Big John 85]

The contact points look new. I don't see any corrosion on them. I can try cleaning them and put a little electrical grease on them.

This car was owned by someone who should have there shop change the wiper blades and dome light bulb. They had the exhaust so F*cked up 4 1/2 inches of pipe was inside the header collector. I had to get a new engine.

Most of the wires under the hood I don't need they were for the computer and thats gone. This is the last electrical issue that I know of so thats good.

[Big John 85]

I put in new lights and greased the connectors last night.

I am going to cruz around tonight for the local back to the fifties car show. The gauge is on full now and hopefully it will start to drop.

[Lady72nRob71]

Originally Posted by Big John 85

The gauge is on full now and hopefully it will start to drop.

Hopefully that is because you filled the gas tank...
Did you get the rest of the gauges to work reliably?

[Big John 85]

I am going to hook up some after-market gauges for now. I have oil pressure, temp and volts.

The tach seams to read more accurate now!

I put on almost 100 miles and the gas gauge hasn't moved yet.(awesome gas milage!!)

I am going to try putting some seafoam in the gas tank tomorrow.

[Big John 85]

The gas gauge is now starting to move. I don't totally trust it yet. It did drop to 1/4 and when I filled up it went back to full. Thanks for the help I would not have thought that the cluster connections would need cleaning.