fuel malfunction-runs out when tank is not empty!

[sirwhite4]

00 C230 K
i picked this up with 105k on it, and its ran out of fuel at 1/4 tank AND 1/2-ish tank! i know its not empty but now i have to refuel at 1/2 tank. any idea what might be causing this?

thanks for any suggestions!

ps im new to the board, so hi!

-jeremy

[benzonline]

Common problem on these cars. I beleive its the fuel sending sensor in the tank?

[timmyj51]

Yeah, pretty sure its a faulty fuel level sending unit. Mine doesn't work
properly but they're expensive to replace so I keep track of
my fuel consumption with the trip odometer.

[w202wraith]

Does about $500 sound right for replacement of the fuel level sending unit? That's what my mechanic is asking for.

[timmyj51]

There's two sending units for your car. First need to know if
just one or both are bad. Can get one for $87 at Arizona
Auto Haus. $150 for the other. According to the Haynes
manual not too hard to replace for DIYers.

[OzC36]

Just to be clear on the problem, there are two possibilities.

1. When your tank is empty, the gauge still indicates 1/4 to 1/2 (this is a gauging error that is usually related to the fuel sensor).

2. When your gauge indicates 1/4 to 1/2, your engine stops due to lack of fuel delivery, but you can verify that there is trapped unusable fuel in your tank (this is caused by trapped fuel that is correctly indicated by your fuel gauge, and is not a fuel sensor error).

If you have the first problem, a good place to start is changing the fuel sensors in the tank - a common problem with W202 Mercs.

On the other hand the second problem could relate to a blockage. Consider that the fuel tank in the W202 is two "saddle" tanks interconnected by a bridge between the two at the top. The system gauges both and allows both tanks to fully feed to the engine. A blockage of the interconnection fuel delivery system would prevent this.

You have now exhausted my knowledge of the fuel system!

[sirwhite4]

sweet, thanks guys!