Flashing Fuel Light

[soldier]

So my 'low fuel' light goes haywire, but not because I'm low on gas

Second time it goes on the 'Check engine' light goes off

from that point forward, everytime the car idles or stops (like at a red), the 'low fuel' light flashes, and continues until engine is turned off

but wait, there's more


I take it to the shop, a fairly reliable one here called McNally's, anyway they figure it's the fuel pressure regulators

so I pay $150 for one and $280 for the other (there's one on each side), plus labour = $700 total, everybody's happy

BUT THIS IS NOT THE END OF THE STORY

hours after I pick up the car, it goes off AGAIN!!!!



WTF




ANYBODY know what this is about?? the shop is telling me to bring it back for another look, but my confidence is shaken

anyone run in to this before?? a flashing 'low fuel' light that goes off when car idles

[stox]

My guess would be that it is the fuel level sensor. There are two in the W202's, one to show the actual level and the other to indicate when fuel is low.

[[ Ignore this response, I was not reading carefully. The low fuel light is "flashing." As ryhi notes below, this is indicative of a vacuum or vapor recirculation issue. ]]

[ryhi]

ive had that problem for over 2 years. i have looked into getting it fixed, but i left it alone as the car runs fine. from what i searched, it has something to do with the EGR valve and/or a fuel vacuum leak. whatever it is, it has to do with emissions, so when i get my car smogged, i just disconnect the battery or clear the codes with a diagnostics tool to get rid of the check engine light for a day or two.

[vinnie201]

try a new gas cap, maybe urs isnt sealing right.

[crazy00c230k]

Originally posted by stox
My guess would be that it is the fuel level sensor. There are two in the W202's, one to show the actual level and the other to indicate when fuel is low.

[[ Ignore this response, I was not reading carefully. The low fuel light is "flashing." As ryhi notes below, this is indicative of a vacuum or vapor recirculation issue. ]]

i had a fuel level sensor go bad and what he is describing is exactly what my car did, replaced the sensor and everything has been fine since

[Nelson Lago]

I KNOW CAPS LOCKS IS ANYOING BUT LISTEN THE BLINKING LOW LEVEL FUEL LIGHT IS AN VACUME LEAK FOR THE EVAP YOU HAVE A LEAK you cant see the leak or smell it, need a smoke mechine to find it..............................hope that helps

[First Benz]

You have one of 4 faulty components.

Gas Cap - Not overly common, but it happens, and umm...your gas cap is tight, right?
Purge valve - I think I've seen 1 of these go bad, so not very likley at all
Charcoal canister shut off valve - Common on other chassis, but not so much on this one, I'd say it's a 2-1 ratio between this and the next thing, with the more often failed component being:
Charcoal canister - This is very common on the 202's.

I would start with a 10$ gas cap, then a shut off valve, then the canister, in that order, if you don't want to go to the dealer to have it fully diagnosed. Here's the catch though, it it ends up being the canister, and not the shut off valve, the new canister comes with a new shut off valve. So then you have 2 new valves.

At least now you have a few different routes to take.

Eric

[vinnie201]

yea i had a leak and replaced the purge valve and now no more engine light. you should touch it to see if it is pulsating, if its not then you need a new purge.

[timmyj51]

it's a 2-1 ratio between this and the next thing, with the more often failed component being:
Charcoal canister - This is very common on the 202's.




I've been thinking of replacing the canister just as
routine maintenance. Know where I can buy one EXCEPT
the stealership?

[First Benz]

Originally posted by timmyj51
it's a 2-1 ratio between this and the next thing, with the more often failed component being:
Charcoal canister - This is very common on the 202's.




I've been thinking of replacing the canister just as
routine maintenance. Know where I can buy one EXCEPT
the stealership?

I'm sure there are places out there to get them aftermarket, but I wouldn't know where to look. Sorry, wish I could help more.

Eric

[soldier]

well, i took it back to the shop and they're telling me the next step is a smoke test

and that there is possibility for a MILLION things to be wrong with this fuel vacuum problem

stupid...worse still it does not affect the car at all

[soldier]

an update on that

the problem has apparently been fixed (fingers crossed)

it was a disconnected fuel hose under the filler (above the rear right wheel well). not sure what the hose is called but it caused the vacuum leak, indicated by the flashing fuel light only when stopped or idle (because gas only fills through it during those times). it also caused a major loss in fuel efficiency, as I was in fact leaking gas whenever I idled

so there it is, hopefully if the light goes off for anybody else this could be a possible cause & fix