Dancing Fuel Guage
 

I have 86 16V and need a little help.

The fuel gauge keep jumping around, and I read something about cleaning the switch which located in the trunk behind the carpet area. As I pull the carpet out, just what am I looking at?! a plug? a switch or what? How do I go about clearning it? or do I have to replace it? Anybody have any pic?? Please any help would be very greatful!!

John16V

It is not a switch, but rather the sending unit that is submerged in the tank that is at fault.

John - mine just recently started on the E320 and based on what I have read it will not hurt anything. I will be replacing mine over the next month or so and may do a diy'er article on it with pictures. Stay tuned.

Whether cleaning or replacing it, make sure you wait until the tank is near empty (1/4 or less).

engatwork,

Maybe I should hold off then, I ll wait until you post a update or DIY...thank-you

John

John - it may be a month before I do it. I try to schedule my outdoor car work when it is cooler.

I know this sounds bizarre, but check your battery and the output of the alternator. When my alternator was dying, my gas guage jumped around and stopped when I replaced the alternator brushes.

gas gauge
 

Chuck-

Hmmm... interesting note on that alternator correlation...

John, I too have a 16v ('87) and my gas gauge was intermittently flickering when tank dropped to around 1/3 or so. But I haven't noticed it lately.

Here's the interesting part that I would never have associated with this: I just had my alternator replaced last month (f'n $465 later I'm now all set!).

While I'm no electro-genius, I haven't seen the gauge flicker since. Maybe there is a correlation? I'd say follow Chuck's advise, can't hurt to get an output test. Good luck! (and go see the 2.3-16 survey thread if you have yet to sound off!).

Enjoy.

Thanx guys, but i don't think is the Alternator because i have my changed few months ago, my alternator were making this high pitch noise...my mechanic said it was the Alt., so I changed it.
I don't know but this dancing thing is driving me crazy!! Could it be the Fuel pump relay?

John

Dancing Fuel Guage
 

I had the same problem on ny 87 420sel and it was the fuel sender unit. It is easly repaierd, thank god cuz a new one was over $100. Remove the sender from the tank. Open it, and you will find a float that mover a shorting bar between two small wires. These wires act as resistance elements. The shorting bar slides up and down along the length. The resistance changes and the guage moves as a result. The problem is that the wires get coated with varnish or something. Using steel wool (very fine 000) gently polish the wires to remove any deposits on them. They are delicate so be careful. The shorting bars which are gold plated now make good contact and the problem should be solved.

Hope it works for you.
:D

I've used a pencil erasor on similar stuff. It's nicer to the gold plating, which is very thin. Maybe you could try that first.

Did you replace the gasket or just reuse the existing one? I pulled the the cover over the gas tank area and exposed the sending unit this weekend but did not pull it out because I did not have a new gasket. May go do it this afternoon. I figure that if I do not mess up the existing one then I should be ok to reuse it. Also, what kind of wrench did you use - that looks like one big mutha nut on there.

Mabey I wasnt clear earlier. Use the steel wool to clean the wires not the shorting bar. Steel wool works good cuz it wraps around the wire and gets it clean all over. And yes its a big nut, I think U used a 1-7/8" socket which required a 3/4" drive. The gasget is rubber and can be reused. I tried to get it out with goose neck pliers but that didnt work. It was quite tight and required the big socket to get it out.

Hey guys,(dpetryk and engatwork )I am lost?! So, after you pull the carpet; you will see the plug (the one that have three hole in it?) Pull it out and you see three pins? correct? Then do you pull that whole piece out?!
( the white piece with the pins sticking out?) What tools do I use?! I know wait till you are almost empty before you do this.

Not a DIY,
John

Let me see if I can clear things up. The thing I was working on was the fuel level sender unit. On a 126 it is located in the fuel tank on the left side. To get access, remove the back seat, and there is a rubber cover plug that has to be removed to gain access to the sender. Take the plug out, remove the electrical connector, and then you need the 1-7/8" socket to unscrew the thing. It is about 1.5" in diameter and about 12" long. Unscrew a small slotted nut from the bottom to remove the outer case and expose the inside working parts. Does that help? Then follow my previous instructions. On a 124 the sender is accessable from the trunk if my memory is still working. Top center of the fuel tank.