Twitchy fuel gauge in 92' W124
 

I know this is a common problem....somewhere below half a tank the needle bounces around sometimes....is this just a fix with a pencil eraser on the sender leads or is it easier, and cheap enough, to just replace the sender unit? I only want to go in there once. Thanks much for your replies.:)

Not much you can do to the old unit as it is a sealed device. The contacts being internal.

I had a similar problem three weeks ago. The needle started tweaking at the last 1/4 level mark then stopped as the level dropped.

I thought of cleaning the sensor myself after reading an excellent posts here but was too lazy to start the process.

Last Sat. I put in a bottle of Fuel System Treatment before the long trip (150 KM one way) :D and the needle did not tweak any more when it hit the 1/4 mark this morning. I assume the problem goes away with the Treatment cleaner.

Hope this helps, good luck.


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1992 300E 125k KM

Well, that's interesting...what brand fuel system treatment? I'll try that first and see what happens.

I can get the new sender for $90...not cheap but not that expensive either way. Thanx guys. :)

I've had similar problems on more than one (older) car and I think it's caused by the wiper not riding over the lower end of the wire wind, which allows deposits to build up over the years. I expect it's more likely to happen if you are in the habit of filling the tank when it gets a little below half as I am.

I tried an experiment on a 1000 mile trip with the 2.6 where I just filled the tank to about half and then let it run to near empty, so the wiper spent plenty to time passing over the lower portion of the wire wind. Had to stop for fuel more often than normal, but as the trip progressed the fuel gage stopped dithering and has not misbehaved since that trip last Thanksgiving.

Duke

Hi Jim,

It's the Pennzoil that i used.

Have a good day.

-J

I've tried the same trick Duke describes its worked both times....I think the problem is caused by crud on the sendor that is dislodged when the sensor passes the dirty spot multiple times.

Its worth a try before you drop $90 on a new sender.

Tim

Right on guys! I'm going to pick up a bottle of that Pennzoil stuff and see if it works...my fingers are crossed.

I'll let y'all know if it works for my car. Thanx much, again. :)

Cool - Me Too!
 

My 1990 W201 2.6 has the same problem ... and I would typically refill the fuel tank ~1/2 empty.

Pennzoil for ME! And, I'll try the "let the fuel tank get empty and don't fill beyond 1/2 full" method too.

mine too...
 

My 92 2.5 turbo diesel does the same thing... more so in the hottest of summer less in the colder winter.. I just learned to live with it mking sure i reset the trip odometer at each fill up.. when aproaching around 500 miles the guage seems to settle down

always something,,
:o