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Cannot Fill Gas

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I have run into the dreaded gas filling problem. Cannot put gas as the nozzle trips after few seconds thinking tank is full.
I checked the canister purge valve and I am not sure if it is working correctly. When I connect it to 12V battery, it makes a tick sound. It only makes a one tick sound when first connected. Should it be making continuous ticking noise? Also I disconnected the hose going to the manifold. Kept the hose going to the charcoal filter connected. There was no vacuum on the intake nozzle, with the power connected and disconnected. Shouldn't there be vacuum on the valve intake when power is connected and engine running? There is vacuum on the hose coming from the canister when engine is running. Is the valve bad? Could it be clogged and shut closed? What is a proper operation of the valve? Any help and suggestion is appreciated.

I called a mechanic to see how much it would cost to clean the hose going from the tank to the charcoal filter, he said if the valve is fine than the cleaning will not help. The charcoal canister is probably clogged and needs to be replaced.

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I have run into the dreaded gas filling problem. Cannot put gas as the nozzle trips after few seconds thinking tank is full.
I checked the canister purge valve and I am not sure if it is working correctly. When I connect it to 12V battery, it makes a tick sound. It only makes a one tick sound when first connected. Should it be making continuous ticking noise? Also I disconnected the hose going to the manifold. Kept the hose going to the charcoal filter connected. There was no vacuum on...
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W163 and General M Gremlin
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Check your shut off valve.

Older thread:
 
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Registered
1999 C280, 2015 C300
Joined
445 Posts
Discussion Starter · #3 ·
Check your shut off valve.

Older thread:
Where is it? Never he
Check your shut off valve.

Older thread:
Where is the shut off valve located. What function does it provide.

I forgot to mention I am also getting P0400 and P0450 codes with CEL on
 

W163 and General M Gremlin
Joined
16,073 Posts
Learn to.......

Community Search, at the top of the thread:
example: Fuel shutoff valve help

One topic/issue per thread. Start a new thread on your error codes.
 

W163 and General M Gremlin
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16,073 Posts
You need to address this first.
When fixed, your code should disappear.
 

Registered
1997 C280 , 2008 S550
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604 Posts
If you are a nerd, you may want to watch this:

 

Registered
1999 C280, 2015 C300
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445 Posts
Discussion Starter · #9 ·
Today I took the car to a mechanic who was kind enough to use his computer on the car. We got following code:

P0450-28 Fuel Tank Pressure Sensor (B4/3)
Purge Monitoring Pressure Sensor (B4/4)

If I am not mistaken the B4/4 is the purge sensor in the engine that I was playing with (photo included in above post). I had it unplugged for a while while I was checking it. It appears to be working. I think the culprit is B4/3 that I think is some where in near the neck of the fuel tank at the back. The mechanic would not quote me an estimate to fix and said it could be anything and he will have to diagnose the problem. He said it could be a simple ground connection missing to replacing everything. Can an expert on this forum give me the location of B4/3 and confirm that B4/4 is the sensor in the canister vapor purge sensor in the engine. Appreciate the help.
 

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1999 C280, 2015 C300
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Discussion Starter · #10 ·
UPDATE: I apologize I should have posted this update earlier. The problem has been fixed.
I disconnected the cannister purge valve and tried to clean it by blowing into it and left it out in the open overnight. I also removed the gas cap and but a plier in hole to keep the flap open for couple of hours. I drove the car for a day without the cannister purge valve. Yes got ECL and all sorts of codes. Connected the CPV and the problem is fixed. No more issues filling gas. Reset the codes and all codes gone :)
 

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1999 C230 Kompressor
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272 Posts
Nice, maybe I'll have to try that. I have the same issue but it will allow me to fill gas, I just have to hold the pump to the fill hole really tight the entire time. I cleaned the purge valve on mine and the problem still persists. (It never looked too dirty in the first place.)

So by removing the gas cap and opening the flap and letting it air out, is that supposed to evaporate any gas that might have flooded the charcoal canister? Which in turn, caused your issue?
 

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1999 C280, 2015 C300
Joined
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Discussion Starter · #12 ·
Nice, maybe I'll have to try that. I have the same issue but it will allow me to fill gas, I just have to hold the pump to the fill hole really tight the entire time. I cleaned the purge valve on mine and the problem still persists. (It never looked too dirty in the first place.)

So by removing the gas cap and opening the flap and letting it air out, is that supposed to evaporate any gas that might have flooded the charcoal canister? Which in turn, caused your issue?
I read about this trick of leaving the gas cap off and letting the air escape somewhere online or maybe on this forum. When you do that make sure you stick a screwdriver or plier end into the gas filler hole to keep the flap open. I also drove the car for a day with the purge valve removed. I could smell gas in the car and got all sorts of code. But that may have also helped in clearing any clogging.
 
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