my friend just picked up a 82 base in great condition, only thing wrong with the car is the gas gauge doesn;t work. Some times it will show full, then go completly empty.

whats up with ot ?
thanskl

 

what should be the frist thing to check or look at ?
thanks again

 

yea mines is not working as well... but mines doesnt ever go up... any help anyone?

 

Did you fill it up with gas?

 

I don't know about gas tanks. Could the sensor be screwed up?

 

Mine does that too... annoying. I'm about ready to drop the tank to figure out what is going on. My tank has to be full also or it runs out of gas after like 3 - 4 gallons used (pickup line must have a problem).

 

Check and clean the wire connections at the sender. If that doesn't solve it, pull the sender and ohm it per the FSM. If it fails, replace it.

 

http://frosted7.com/katrina5.html

 

^ Awesome writeup.

 

This is interesting, I just was looking at the FSM and wiring diagrams this past week to see why the gas guage is off. Mine typically only reads 3/4 full at full tank and doesn't really reflect reality from then on. I just fill up after every 150 miles or so but it would be nice to get this working.

Anyway, what I noticed is that the gauge works by measuring the resistance and that when the tanlk is full the resistance should be the lowest (~7ohms) and when its empty the resistance is the highest (~95ohms). So it dawned on me that if the circuit is experiencing any extra resistance then its always going to show less full on the gauge than it really is.

My suspicion is that over the years the connection gets corroded at the tank (as the write up shows) and the ground for the gauge connection is bad as well. I cleaned up my connection last year and it marginally helped. I didn't pull the sender because the mounting screws are so corroded I was sure they would strip trying to get it out. For now I'm assuming the sender itself is ok. May be a bad assumption on my part but we'll see.

Next I'm going to trace the sender wires back to the cluster and ohm out from both ends to see what the resistance is and go through all the under dash connections and pull them, clean them and put it all back together plus make sure the ground strap for the dash is a good ground. I'm betting a lot of these sender issues are related to a poor ground in the circuit.

 

help me out, FSM = ?

fuel sending mechanisim, don't laf thats the best I could think of with the situation.

 

thats a good page, I think that will clear this problem up

 

damm darkfrost you win for owning the most rusted car I think I have ever seen

 

FSM-Factory Service Manual. Link to the online ones are in my sig.

When getting a partial reading on the fuel gauge, it's usually because the fine wires inside the sender, that vary the resistance, have worn and broken. Replacement is the only repair.