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2002 MB E55 AMG
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25 Posts
Discussion Starter #1 (Edited)
I've been pulling my hair out with filling the gas tank on my 02 E55. See my earlier post
http://www.benzworld.org/forums/w210-e50-amg-e55-amg/1577611-cant-fill-gas-tank-keeps-shutting.html

Today, I took off the large vent hose on the top of the canister that goes to the fuel tank, car filled up easily, no gurgling trying to get the gas to go in.

I replace the vent valve last year, didn't help. When I checked the vent valve, not sure if there is a coil in the valve, or if the two electric terminals are just a contact, the ohmmeter reading was 0 ohms, so if there is a coil, is it shorted? Does anyone know if the terminals are connected to an internal switch or a coil in the vent valve? If it is shorted, could it have harmed/burned out any other electric circuits?

When I blow into the large inlet at the top of the canister, the air comes out of one of the bottom fittings on the canister, so I don't think it's clogged.

I hate to buy a $500 charcoal canister or another $150 vent valve.

I tempted to just leave the vent hose disconnected:surrender:

Can anyone explain how the whole system is supposed to work?
 

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W202 00 C200
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239 Posts
I had a strange problem, started to loosing power &feeling that the car goes to the lean point & sometimes the car shut down

while fill the tank,, i can tell you how bad the car behave,, i repalced (MAF-Fuel pump-"2" Fuel pump Relays-CPS sensor-Cam

sensor-Spark Wires & plugs),, with NO luck,,

when i replaced that damn Charcoal canister filter, the car is back to life,, with fantastic power, Happy to drive it........

*Don’t forget to check the Purge valve either.......

Activated Charcoal Filter - MBWorld.org Forums

ZAYED,,
 

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1994 sold/new White 2014 c250 sport/night eition
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177 Posts
Can anyone explain how the whole system is supposed to work?

Carbon Canisters are devices found in cars designed to decrease the amount of air pollution the vehicle creates while at the same time increasing its fuel efficiency. Even when the vehicle's engine is turned off, hydrocarbons are produced. This occurs in the form of fuel vapor rising in the fuel tank. Carbon Canisters trap that vapor rather than allow it to escape the fuel tank, feeding it back into the engine.

Carbon Canisters are rectangular shaped boxes that sit apart from the fuel tank next to the throttle in most vehicles. There is an input port and an output port, with the two ports side by side. There are three chambers inside the canister, running in sequence from the intake to the outtake. The interior of the canister is filled with charcoal or carbon pellets. The input of the canister connects to the gas tank's vent port, while the output connects to the purge valve in the side of the vehicle's intake manifold.

When the vehicle is shut off, there is a pressure imbalance within the fuel tank caused by fuel being siphoned out, but no air being let back in to take up the empty space. The lower pressure in the gas tank promotes a greater rate of evaporation, letting some of the fuel become a gas. Eventually the tank's internal pressure equalizes, at which point the gas leaves the tank through the vent port and goes into the carbon canister. It's trapped there by the properties of the carbon within the canister, keeping it from escaping into the air. When the vehicle's engine starts, the sudden suction created along the intake manifold opens up the purge valve and pulls all the gaseous fuel out of the canister and burns it in the engine. The canister goes unused until the car is turned off again.

Hpe this helps.....:thumbsup:
 

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2002 MB E55 AMG
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25 Posts
Discussion Starter #4
Thanks for the explanation. I replaced the purge valve, checked the line from the purge valve to the charcoal canister, its clear. Otherwise car runs great, I can go below 1/4 tank and no issue. Just on trying to get gas in.
 
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