PURGE VALVE and Charcoal canister

[French02chris]

Moderator edit: See post #58 for the final solution.

Hello all....

I have been chasing an issue for the past couple of weeks

long story short : car starts great in cold start and runs great....when I shut off the engine and try to restart, it takes longer ( 2.5 seconds instead of 1.2 or so)
it is NOT ignition related ( caps , rotors, plugs, insulator (dry!!) , etc are all good)....I believe it is fuel related

I did a test where i drove without the fuel tank cap and the car was acting better after every restart ( still long crank, but not sluggish anymore)

ANYWAY, my question is about the PURGE VALVE : when i remove it, there is always some charcoal bits falling out of it!!! IS IT NORMAL ? or do i need a new charcoal canister????
Today, I will drive to Oreilly autoparts to get some MAF cleaner and clean the purge valve too.

Thank you

 

[gerryvz]

Replace it as Indid mine two years ago. You will only be the second person in the history of this forum to ever replace your purge valve. 99% of people’s purge valves are non-op and either people don’t know or don’t care, LOL.

Deferred maintenance, you know…..

 

[gsxr]

long story short : car starts great in cold start and runs great....when I shut off the engine and try to restart, it takes longer ( 2.5 seconds instead of 1.2 or so)
it is NOT ignition related ( caps , rotors, plugs, insulator (dry!!) , etc are all good)....I believe it is fuel related

I did a test where i drove without the fuel tank cap and the car was acting better after every restart ( still long crank, but not sluggish anymore)

Removing the tank cap is likely a coincidence and should have nothing to do with the sluggishness.

ANYWAY, my question is about the PURGE VALVE : when i remove it, there is always some charcoal bits falling out of it!!! IS IT NORMAL ? or do i need a new charcoal canister????

I don't believe that is normal, but it also shouldn't cause the problem you are having.

Today, I will drive to Oreilly autoparts to get some MAF cleaner and clean the purge valve too. Thank you

As a test you can block off the purge valve and see if there is any difference. The only function of the valve is to let the engine consume stored vapors from the canister. If the valve isn't working, the canister is still vented to atmosphere.

 

[gerryvz]

And yes, failed purge valves love to leak little charcoal "BB" balls into the hand. It's a $120 (last time I checked) deferred maintenance item, and takes all of 15 minutes to replace.

OWNER - a777fan (E420) | Owners and Their Cars

I had a pulsing idle early on about 6 weeks after replacing caps. Turned out that the PS dizzy was loose enough to shake slightly when I grabbed it. I would get a rhythmic Idle surge at traffic lights 500-625 RPM (not specific but you get the gist) and I could also feel it in the pedal at...

www.500eboard.co

Detailed here.

 

[French02chris]

Removing the tank cap is likely a coincidence and should have nothing to do with the sluggishness.



I don't believe that is normal, but it also shouldn't cause the problem you are having.



As a test you can block off the purge valve and see if there is any difference. The only function of the valve is to let the engine consume stored vapors from the canister. If the valve isn't working, the canister is still vented to atmosphere.

what would make charcoal getting into the purge valve???? failling canister? ( those are still available and cheap)

 

[French02chris]

And yes, failed purge valves love to leak little charcoal "BB" balls into the hand. It's a $120 (last time I checked) deferred maintenance item, and takes all of 15 minutes to replace.

OWNER - a777fan (E420) | Owners and Their Cars

I had a pulsing idle early on about 6 weeks after replacing caps. Turned out that the PS dizzy was loose enough to shake slightly when I grabbed it. I would get a rhythmic Idle surge at traffic lights 500-625 RPM (not specific but you get the gist) and I could also feel it in the pedal at...

www.500eboard.co

Detailed here.

SO, it's not the charcoal canister itself getting "bad" ??

 

[gsxr]

The charcoal is coming from the canister and the debris could plug the purge valve. I've not purchased a new canister but I would presume the carbon isn't supposed to fall out.

Again, this should have nothing to do with your sluggish engine operation. The few bits of carbon would just get ingested through the intake.

 

[French02chris]

The charcoal is coming from the canister and the debris could plug the purge valve. I've not purchased a new canister but I would presume the carbon isn't supposed to fall out.

Again, this should have nothing to do with your sluggish engine operation. The few bits of carbon would just get ingested through the intake.

great..thank you!!
So , i guess that I will have to monitor the fuel pressure while driving around....especially after a hot restart ( since cold start driving is great!! )

 

[French02chris]

LITTLE UPDATE :
switched to another ( new that I had in my trunk) purge valve : NO DIFFERENCE IN HARD STARTING after an engine shutoff and restart...
SO, purge valve is NOT the issue

TEST #1 today : PUT GAS CAP ON ...drove 10 miles to store, turn off car.....went to start again : hard start and a little sluggish...drove to store #2

TEST #2 today : REMOVE GAS CAP again when i arrived at store #2...went shopping....Started car again : hard start but NO sluggishness!!!!....

call me crazy, but removing the cap on my car does make a difference.....MAYBE the fuel tank vent valve is dead???

 

[nocfn]

If nothing else the tank valve ahould be replaced. Pressures could crush your tank. Might be an issue for sure

 

[gerryvz]

As I mentioned, you can test a purge valve with a 9volt battery. No clicking when you hit the terminals with the battery, valve no good. I had a spare and it was no good, which is why I got the new one.

 

[gsxr]

call me crazy, but removing the cap on my car does make a difference.....MAYBE the fuel tank vent valve is dead???

Mr. Crazy, it's far more likely to be coincidence. The pumps will push pressure to the rail regardless of tank venting. Tank vent issues will collapse the tank, not cause problems with engine output.

 

[French02chris]

Mr. Crazy, it's far more likely to be coincidence. The pumps will push pressure to the rail regardless of tank venting. Tank vent issues will collapse the tank, not cause problems with engine output.

wouldn't a coincidence happens once? and not 3 times?
that's just a weird coincidence then..lol
anyway, I also check the ohms value of the CKP and it seems to be in specs ( from a video that i watched from Pierre Hedary)

 

[gsxr]

wouldn't a coincidence happens once? and not 3 times?
that's just a weird coincidence then..lol

If you can repeat it consistently regardless of time & temperature, what would be interesting. But for now I'm still sticking with "coincidence".

anyway, I also check the ohms value of the CKP and it seems to be in specs ( from a video that i watched from Pierre Hedary)

CKP can measure in spec and have zero fault codes, and still cause some very bizarre behavior. It's extremely unusual, as the typical failure is a non-start issue when hot, but that is not the only problem the CKP can cause. I spent months chasing down an intermittent power problem on a car and in the end it turned out to be a combination of ETA and CKP. Felt very much like a loss of fuel pressure but I was able to drive with a remote gauge and see the pressure remained normal when it lost power, so I ruled that out early on.

 

[French02chris]

As I mentioned, you can test a purge valve with a 9volt battery. No clicking when you hit the terminals with the battery, valve no good. I had a spare and it was no good, which is why I got the new one.

How exactly do you do that? .. I have a 9v battery but it doesn't really fit/connect to the purge valve terminals?? How do you connect them
(my 9v battery comes from my little voltmeter)
Also my purge valve does click wen I am driving under a cold start

EDIT : no click with the 9v battery ( looking at the photos on your post about purge valve)....
I tried both purge valves and none of them are clicking applying the 9v battery..so
-my 9v maybe weak?!
- or those 2 valves are not working ( however, with engine on in the morning...the valve definitely clicks!!!!)
also the "new" valve has been in the car since 2020 ( bought it new...OE Mercedes part).....I would think that they last longer than 2 years???

 

[gsxr]

Normally the valve will click with 9V applied. This is a rough test however, a full test requires blowing through the valve while turning it on/off (with 9V). Easier with valve removed, which is a minor nuisance. I've found some valves may click, but now allow normal airflow. A good valve, when open is easy to blow through - almost zero resistance.

Think I posted about this a year or two ago, but I found a similar issue with one of my cars. Carbon bits fell out of the failed/stuck purge valve, I replaced it with a good used one, and the good used one died in short order - also plugged with carbon bits. Briefly bypassed the valve with engine running and I could hear carbon bits getting sucked through the tubes! So I went spelunking, pulled the canister and found it was "leaking" carbon bits - which can't be normal. I assume there should be some sort of screen or filter media that is supposed to contain the carbon.

At the time, I was trying to figure out if a purge valve problem could in any way cause the fuel tank to collapse, i.e. if the purge valve was somehow related to venting. After tracing out the hoses & canister connections, it seems that the canister is vented to atmosphere anyway. The purge valve just cycles to suck gasoline vapors into the engine for reduced emissions. But if the valve is stuck closed, or if the tubes are blocked off, there should be no change in engine operation. Now, if the purge valve is stuck WIDE OPEN, this could cause a vacuum leak and/or suck carbon bits into the engine.

If you have carbon bits in the tubing or falling out of the canister, and want to fix the system, it likely needs a new canister - then verify the valve is working and isn't partly blocked. But don't put a new valve on with carbon bits in the system or they could possibly cause the new valve (~$100!) to fail.

 

[195910]

The can is soaked in fuel pulled from the tank due to a stuck valve.. You will need to replace both.

 

[French02chris]

The can is soaked in fuel pulled from the tank due to a stuck valve.. You will need to replace both.

are you talking about the purge valve or the tank vent valve??

 

[195910]

are you talking about the purge valve or the tank vent valve??

Purge valve

 

[French02chris]

Normally the valve will click with 9V applied. This is a rough test however, a full test requires blowing through the valve while turning it on/off (with 9V). Easier with valve removed, which is a minor nuisance. I've found some valves may click, but now allow normal airflow. A good valve, when open is easy to blow through - almost zero resistance.

Think I posted about this a year or two ago, but I found a similar issue with one of my cars. Carbon bits fell out of the failed/stuck purge valve, I replaced it with a good used one, and the good used one died in short order - also plugged with carbon bits. Briefly bypassed the valve with engine running and I could hear carbon bits getting sucked through the tubes! So I went spelunking, pulled the canister and found it was "leaking" carbon bits - which can't be normal. I assume there should be some sort of screen or filter media that is supposed to contain the carbon.

At the time, I was trying to figure out if a purge valve problem could in any way cause the fuel tank to collapse, i.e. if the purge valve was somehow related to venting. After tracing out the hoses & canister connections, it seems that the canister is vented to atmosphere anyway. The purge valve just cycles to suck gasoline vapors into the engine for reduced emissions. But if the valve is stuck closed, or if the tubes are blocked off, there should be no change in engine operation. Now, if the purge valve is stuck WIDE OPEN, this could cause a vacuum leak and/or suck carbon bits into the engine.

If you have carbon bits in the tubing or falling out of the canister, and want to fix the system, it likely needs a new canister - then verify the valve is working and isn't partly blocked. But don't put a new valve on with carbon bits in the system or they could possibly cause the new valve (~$100!) to fail.

I have a new canister coming this week...( still a cheap part )

However, if i understand right, those are 2 separate issues and it is NOT the cause of my hard start ( 2.5 seconds) when engine is at temperature??

 

[French02chris]

Purge valve

Normally the valve will click with 9V applied. This is a rough test however, a full test requires blowing through the valve while turning it on/off (with 9V). Easier with valve removed, which is a minor nuisance. I've found some valves may click, but now allow normal airflow. A good valve, when open is easy to blow through - almost zero resistance.

Think I posted about this a year or two ago, but I found a similar issue with one of my cars. Carbon bits fell out of the failed/stuck purge valve, I replaced it with a good used one, and the good used one died in short order - also plugged with carbon bits. Briefly bypassed the valve with engine running and I could hear carbon bits getting sucked through the tubes! So I went spelunking, pulled the canister and found it was "leaking" carbon bits - which can't be normal. I assume there should be some sort of screen or filter media that is supposed to contain the carbon.

At the time, I was trying to figure out if a purge valve problem could in any way cause the fuel tank to collapse, i.e. if the purge valve was somehow related to venting. After tracing out the hoses & canister connections, it seems that the canister is vented to atmosphere anyway. The purge valve just cycles to suck gasoline vapors into the engine for reduced emissions. But if the valve is stuck closed, or if the tubes are blocked off, there should be no change in engine operation. Now, if the purge valve is stuck WIDE OPEN, this could cause a vacuum leak and/or suck carbon bits into the engine.

If you have carbon bits in the tubing or falling out of the canister, and want to fix the system, it likely needs a new canister - then verify the valve is working and isn't partly blocked. But don't put a new valve on with carbon bits in the system or they could possibly cause the new valve (~$100!) to fail.

also are you saying that even though my purge valve is pulsating when engine is on ( after a cold start and for a few seconds at a short drive), it is possible that it is not working correctly??? when I remove the valve and blow thru it, no air is passing thru ( so out of the engine , the valve is definitely close) .
I need to find a new 9v battery as the one that i have in my voltmeter might be weak!?!

 

[195910]

also are you saying that even though my purge valve is pulsating when engine is on ( after a cold start and for a few seconds at a short drive), it is possible that it is not working correctly??? when I remove the valve and blow thru it, no air is passing thru ( so out of the engine , the valve is definitely close) .
I need to find a new 9v battery as the one that i have in my voltmeter might be weak!?!

The valve can get stuck again once new debris clogs it, change the canister first.

 

[French02chris]

The valve can get stuck again once new debris clogs it, change the canister first.

trying to figure out what to change or not......don't want to change parts that i don't need to change right now...LOL

Would a stuck purge valve cause my hard starting when engine is warm????
I am just trying to triple check stuff

 

[French02chris]

I also promise that I will update all my posts when my issue is solved....might take a few weeks or not!!! LOL

 

[195910]

trying to figure out what to change or not......don't want to change parts that i don't need to change right now...LOL

Would a stuck purge valve cause my hard starting when engine is warm????
I am just trying to triple check stuff

Yes only when warm. Check if the fuel tank has negative pressure (feels like a vacuum when opening the tank cap), after a relatively long drive open the tank cap with a napkin and see what direction the napkin moves.

 

[JC220]

Did you check for moisture behind distributer caps when warm?

 

[French02chris]

Did you check for moisture behind distributer caps when warm?

Not the issue. It's always dry... I checked several times

 

[French02chris]

Yes only when warm. Check if the fuel tank has negative pressure (feels like a vacuum when opening the tank cap), after a relatively long drive open the tank cap with a napkin and see what direction the napkin moves.

Should napkin go in or out??

 

[195910]

Should napkin go in or out??

In, as if its being sucked into the tank. You can tell from the sound as well, but I thought I would suggest an easier method.
This would only happen on a warm engine after a drive.

 

[French02chris]

In, as if its being sucked into the tank. You can tell from the sound as well, but I thought I would suggest an easier method.
This would only happen on a warm engine after a drive.

What does it mean if the napkin go the outer way??

 

[gsxr]

NORMAL operation causes PRESSURE in the fuel tank, and air should blow OUT when you remove the cap. Or, there may be neutral pressure with no air blowing in or out.

If there is ever vacuum in the tank, sucking air inward, the tank vent is likely stuck and needs replacement ASAP. If this is the case, you will be very fortunate if the tank has not collapsed at all. Sometimes it can collapse just a little, reducing tank capacity a few gallons, but the more it collapses the more likely it will crack and leak. However, the engine will run 100% normally with this problem. No issues starting.

I still do not see how an issue with the carbon canister could cause hard starting when warm, even if the purge valve was stuck partly or fully open. If the valve is fully closed, it cannot affect starting at all.

 

[JC220]

To clarify does this car always have a slow start when hot?

And have you also observed the fuel pressure during a bad hot start cycle? Or was the fuel pressure fine and startup fine during tests?

 

[French02chris]

To clarify does this car always have a slow start when hot?

And have you also observed the fuel pressure during a bad hot start cycle? Or was the fuel pressure fine and startup fine during tests?

Fuel pressure is perfect (at cold start as well as hot start)
And yes, always a slow start (2.5 seconds or so) when engine is at temperature (it started doing it 2 weeks ago)

 

[gsxr]

2.5 seconds isn't terrible IMO, although a bit longer than expected. If it was 5-7 seconds or more, that would be messed up.

I'd focus more on the sluggishness, assuming the engine rarely needs more than ~3 seconds of cranking to fire when hot.

 

[French02chris]

NORMAL operation causes PRESSURE in the fuel tank, and air should blow OUT when you remove the cap. Or, there may be neutral pressure with no air blowing in or out.

If there is ever vacuum in the tank, sucking air inward, the tank vent is likely stuck and needs replacement ASAP. If this is the case, you will be very fortunate if the tank has not collapsed at all. Sometimes it can collapse just a little, reducing tank capacity a few gallons, but the more it collapses the more likely it will crack and leak. However, the engine will run 100% normally with this problem. No issues starting.

I still do not see how an issue with the carbon canister could cause hard starting when warm, even if the purge valve was stuck partly or fully open. If the valve is fully closed, it cannot affect starting at all.

last time that i refilled , I put 15.72 gallons at Shell, and the tank was not fully empty....also I checked it from the trunk and it looks great

 

[gsxr]

last time that i refilled , I put 15.72 gallons at Shell, and the tank was not fully empty....

Sounds normal, although next time wait for the reserve light to come on and then fill up. Generally should take ~16.0 gallons when the reserve light stops flickering and is on continuously.

also I checked it from the trunk and it looks great

Can't tell visually from the trunk, when collapsed 15-20% the tank can look perfect but have the back side sucked inward. BT, DT. By the time they are collapsed enough to see from the trunk side it would probably take less than 10 gallons to fill and you'd have noticed that by now, lol.

 

[cole67]

Removed the purge valve today and cleaned the charcoal pieces from the inlet side of the valve. I’ve cleaned this multiple times and I think charcoal canister should be replaced. I looked up on mboem and noticed 124 470 03 59 is $48.17. Does that sound right? That’s down right reasonable .

 

[Jlaa]

Removed the purge valve today and cleaned the charcoal pieces from the inlet side of the valve. I’ve cleaned this multiple times and I think charcoal canister should be replaced. I looked up on mboem and noticed 124 470 03 59 is $48.17. Does that sound right? That’s down right reasonable .

That is correct. In addition to the charcoal canister, if you are freshening up your fuel system, you may wish to replace the following (I drew up the diagrams when I did a fuel system refresh...)

 

[gerryvz]

Your MOT purge valve is toast. Get a new one. MB part number 000 470 21 93

Expect $95-100. Valve - (000-470-21-93) | Get Mercedes Parts

The MOT purge valve is shown here:

RESTO PROJECT: M119 / W124 / E500 Engine Top-End Refresh | Member Roadtrips and Project Journals

:update: I just got notification from MB Annapolis that there are two of the regeneration valves in the Robbinsville, NJ warehouse, and that the ordered valve will be here in town for pickup tomorrow (Friday). So this means I can button things up over the weekend, at least with the inner...

www.500eboard.co

Charcoal canister: Vapor Canister - 1986-1997 Mercedes-Benz (124-470-03-59) | Get Mercedes Parts

If the purge valve doesn't audibly click when you put a 9-volt battery to the posts, it's dead and needs changing.

You should change both the canister and valve together.

 

[cole67]

Thanks for sharing guys. Great diagrams for the slump stock stuff Jlaa!!!

I've replaced a lot of these parts in 2013 while doing the engine swap including the purge valve. The valve I removed in 2013 still cycles, as does the new one, and they appear to seat well when tested. I believe they're still pulling vacuum due to the quantity of charcoal that builds up on the inlet. Must be a mesh screen in the canister that's probably rotted out.

I've only put about 10k miles on her in the last 10 years. I'm praying that the fender liner and associated canister mounting disassemble without damage. The under carriage plastics are weakening and don't like being disturbed. These cars are getting old- as are some of us

 

[gsxr]

Ive replaced a lot of these parts in 2013 while doing the engine swap including the purge valve. The valve I removed in 2013 still cycles, as does the new one, and they appear to seat well when tested. I believe theyre still pulling vacuum due to the quantity of charcoal that builds up on the inlet. Must be a mesh screen in the canister thats probably rotted out.

That's my theory too... a failed internal screen is letting carbon particles escape.

After repairing/replacing, test your new/recent purge valve to make SURE that with no voltage applied, it is fully closed - cannot blow air through in either direction. It should open & allow airflow with voltage applied. It's critical that it is closed/sealed without voltage, or you end up with a vacuum leak which can cause other issues.

 

[Alphasud40]

Thats my theory too... a failed internal screen is letting carbon particles escape.

After repairing/replacing, test your new/recent purge valve to make SURE that with no voltage applied, it is fully closed - cannot blow air through in either direction. It should open & allow airflow with voltage applied. Its critical that it is closed/sealed without voltage, or you end up with a vacuum leak which can cause other issues.

Yes, charcoal canisters have a filter mesh that fails and is fairly common in the industry. OBD2 cars require the charcoal canister purge valve to remain closed when they are not energized. If they stick open from carbon granules or mechanical failure not only will you get a check engine light but in some cases customers can experience a crank no start after refueling. A Porsche trait with the 986 and 996 cars.

 

[Ascension]

In, as if its being sucked into the tank. You can tell from the sound as well, but I thought I would suggest an easier method.
This would only happen on a warm engine after a drive.

WRONG!! If you have vacuum you have a bad tank vent and could crush your fuel tank. These cars should NEVER have vacuum on the gas cap, they should blow OUT with a whoosh not suck in when you remove the cap to fuel your car.

 

[195910]

WRONG!! If you have vacuum you have a bad tank vent and could crush your fuel tank. These cars should NEVER have vacuum on the gas cap, they should blow OUT with a whoosh not suck in when you remove the cap to fuel your car.

Hi everyone,

The venting system can cause serious issues, but it differs from one chassis to another. The W202/W210 have a different fuel tank system than the W124 which causes different symptoms to occur.

Can someone confirm if the W202/W210 also have pressure (not vacuum) in the tank? I don't have vacuum in the tank when opening the fuel cap but I can't feel pressure either, I have other symptoms related to fuel tank purging.
Running the engine with and without the gas cap in place does not make a difference, I can't fill gas when the tank is nearly empty, but the vent valve IS CLOSED ! this could be an intermittent issue too.

 

[gsxr]

The venting system can cause serious issues, but it differs from one chassis to another. The W202/W210 have a different fuel tank system than the W124 which causes different symptoms to occur.

Can someone confirm if the W202/W210 also have pressure (not vacuum) in the tank? I dont have vacuum in the tank when opening the fuel cap but I cant feel pressure either, I have other symptoms related to fuel tank purging.

The W210 does have a completely different vent system. AND, the system changed significantly between 1996-97 and 1998-2002 (at least on USA models). I have never experienced pressure in the W210 tank, ever, over 10+ years of ownership. AFAICT this is normal, but it is very bad for long-term storage as it will allow fuel in the tank to evaporate over months/years.

Not sure about the W202 systems - never owned a 202.

 

[Alphasud40]

Since OBD2 became a requirement on all 96 model year cars sold in the US Changes were made to the evaporative emissions system. OBD2 requirements called for leak detection in the evap. system. With the old systems fuel vapors were captured and held in the evaporative system. There was no outside vent to atmosphere and all gasses were passed through the purge valve during engine operation. This is why pressure was allowed to build in the system. So when you uncapped the tank or refueled all vapors would escape to atmosphere.

New systems were designed to process fuel vapors when the vehicle sat or was refueled. All vapors were processed through the activated charcoal and then to atmosphere through a canister close valve. When the vehicle was in operation the purge valve was then used to purge or cleanse the activated charcoal. Then along with the close valve, a purge valve, and a pressure sensor the system could be closed and the ECU could then perform leak detection based on written parameters.

You should never have pressure building in modern systems after 1996. If a close valve malfunctions you can’t fuel the tank. If a purge valve sticks open during refueling raw gas can enter the intake manifold and create a crank no start due to over fueling.

 

[195910]

@gsxr @Alphasud40

Thank you for the information gentlemen. In addition to what was mentioned, the post 1998 OBD2 cars have a diagnosis mechanism for the entire EVAP, an additional closing valve is connected to the charcoal canister venting valve.

The car in question (my 12/1996 C36 AMG) is a transitional car (ME + OBD1) with a W210 style fuel system, the filler neck connects to a small plastic tank, this in turn is feeds the main fuel tank. topping up is not allowed as the small tank is for fuel vapor. I was not sure if I should still get positive pressure (air out of the tank) with this system.

I suspect a sticking valve causing an intermittent rich/lean condition.

 

[Ascension]

Hi everyone,

The venting system can cause serious issues, but it differs from one chassis to another. The W202/W210 have a different fuel tank system than the W124 which causes different symptoms to occur.

Can someone confirm if the W202/W210 also have pressure (not vacuum) in the tank? I dont have vacuum in the tank when opening the fuel cap but I cant feel pressure either, I have other symptoms related to fuel tank purging.
Running the engine with and without the gas cap in place does not make a difference, I cant fill gas when the tank is nearly empty, but the vent valve IS CLOSED ! this could be an intermittent issue too.

Correct. To be clear on my response I was referring in particular to the fuel system on the 124 cars. With that system it should have some pressure in the tank and absolutely NEVER should be holding vacuum. If a 124 series car is holding vacuum in the tank it's potentialy a very serious problem that can lead to a crushed fuel tank and fuel leaks. Am aware that the later systems were different due to environmental regs.

 

[gerryvz]

If anyone is interested in what the charcoal canister looks like, here are a few photos. Currently they are Mann branded, and are made in Bosnia-Herzegovenia.

Overview of the black-painted cylindrical filter canister:


End of the canister, with cover for the ports, as well as the MB name, part number and manufacturer:


Box and MB part label:

 

[RicardoD]

OMG, please stop with the list of parts I must hoard / replace on my E500. My car runs great and who knows if my purge valve is working or what the inside of my charcoal canister looks like. I hope mild California climate means these bits last forever.