300E Jumpy Fuel Needle
 

Hey everyone, my fuel needle has been jumpy or just doesnt read accuratley at all.. it will read a half a tank then go down to empty and the light will come on, and sometimes be at half a tank with the light on..

I replaced the whole sending unit in the back of the car but it is still doing it.. do i have a faulty gauge?? Could it be a short in the wires?

The low light is activated by a contact closed in a separate circuit when the sending unit float descends to the bottom. This simply cannot happen if the fuel in the tank is above that level. I would doubt if your problem is related to the sending unit, more likely the wiring or at the readout end.

Steve

Had the same problem with my 90 300SE.
Put up with it for 2 years. Dealer said it was the sender.
I replaced the sender. Still didn't work. Then I replaced the gauge. Worked for about 3 months. Thought it was the gauge so I sent it out for repair. $65.00 later it was found to be good.

I always thought it was a ground somewhere. I ran a new ground from the sender. Still didn't help. Finally I ran a new signal wire from the sender connector to the gauge cluster connector.
Problem Solved for 6 months now!!!!

Took about 2 hours to run the new wire and make it "factory" looking.


BTW, I have a new sender for a 126 car that has 0 miles on it.

Hope that helps,
Dan

one option is to wait it out. my 300e had this problem for about 2 weeks, then it just went away. that was about 2 months ago and it hasn't returned yet. Although I'm sure it will eventually.

Me too.
New sending unit, same deal.
Given the number of posts, must be a common problem.
I'm liking Dan's 'bypass' wiring idea, just to see if there is a short in the wire somewhere.