Glyn M Ruck

Here are the different clamping systems & how to's.

https://mbworld.org/forums/attachmen...se-latch-1.pdf

https://mbworld.org/forums/attachmen...vel-sensor.pdf

https://mbworld.org/forums/attachmen...-fuel-pump.pdf

mecca281

I ordered the new purge valve. Hopefully this fixes the vibration.

I wonder based on Rudeneys comment on pressure equalization in the tank halves, how many different valves contribute towards pressure relief/equalization in the fuel system? are these valves related electronically, (ie disconnecting one, disables the rest of the system, which would mean reconnecting a new "working purge valve" may resume the same vibration"

Glyn M Ruck

There are no equalising valves

mecca281

I may be imagining things, but it "feels" like whatever is wrong, has also been affecting acceleration performance.

If you could, pls explain what you mean by pressure equalization between the two tank halves.. do you mean as the fuel sloshes around while driving?

mecca281

so there is just one valve in the fuel tank/pump system? the eecs purge valve?

Glyn M Ruck

Yes.

The only other device is the pressure regulator that is built into the filter. The system circulates fuel in a fashion that always keeps the pump side of the saddle tanks a little more full than the other side. They don't truly equalise.

Rudeney

Glyn, my understanding is it is that return flow system is used to equalize the fuel levels in the two tank halves and that the hoses between them uses valves to make that possible, and also to keep odd things happening during hard maneuvers.

The tapping sounds I hear on these pumps are said to be those valves. When I worked at the dealership, I saw this on both sides - service and sales. Sometimes an astute customer would notice this on a demo ride, but we also had several complaints come through service, again, almost always on W209 cabriolets. And like I said, this only happens briefly, usually during return to idle, then stops.

Glyn M Ruck

No valves that I have ever seen.

Anyway ~ mecca's noise is clearly the EECS system.

EDIT ~ I think what people always hear is the purge system. I am always vaguely aware of the purge system under certain conditions & that goes for I4, V6 & V8 cars. But I hear that vague flutter as always coming from the front LHS.

I only ever pick it up on the W209 when I have my car serviced. They always shut down HVAC & Radio during the service & return the car to you that way. When I start the car & go on a post service test drive with the WS Manager I can just hear it front LHS before I turn on the fan & radio. My fan runs continuously. I like air on my face.

Maybe EECS pipework routing on the Cabrio is slightly different to the Coupe making it more inclined to transmit the noise of the purge valve.

My C240 had a particularly quiet purge valve that never got noisy but others have had different experience with angry loud ticking up front as the miles rise. South African built W203's always rubber mounted the purge valve & it's attachment bracket. I have seen German & other assembled W203's with the mounting bracket screwed hard onto the strut tower like this. No rubber pad.

mecca281

New Valve....Same Noise....

Its like I feared... The noise goes away only when I unplug the valve.

Glyn M Ruck

I was worried that might be the case. It was evident that your valve had not started the loud ticking yet & was still transmitting noise.

The only other thing I can suggest is that you trace the purge system all the way from the valve to the rear of the car. Make sure everything is properly mounted & not touching anything. The pipework obviously does not have a leak or you would be throwing codes, namely:

P0440 Evaporative Emission Control System Malfunction
P0441 Evaporative Emission Control System Incorrect Purge
Flow
P0442 Evaporative Emission Control System Leak Detected
(small leak)
P0443 Evaporative Emission Control System Purge Control
Valve Circuit Malfunction
P0444 Evaporative Emission Control System Purge Control
Valve Circuit Open
P0445 Evaporative Emission Control System Purge Control
Valve Circuit Shorted
P0446 Evaporative Emission Control System Vent Control
Circuit Malfunction
P0447 Evaporative Emission Control System Vent Control
Circuit Open
P0448 Evaporative Emission Control System Vent Control
Circuit Shorted
P0449 Evaporative Emission Control System Vent Valve/
Solenoid Circuit Malfunction
P0450 Evaporative Emission Control System Pressure Sensor
Malfunction
P0451 Evaporative Emission Control System Pressure Sensor
Range/Performance
P0452 Evaporative Emission Control System Pressure Sensor
Low Input
P0453 Evaporative Emission Control System Pressure Sensor
High Input
P0454 Evaporative Emission Control System Pressure Sensor
Intermittent
P0455 Evaporative Emission Control System Leak Detected
(gross leak)
P0456 Evaporative Emission Control System Leak Detected
(very small leak)
P0457 Evaporative Emission Control System Leak Detected
(fuel cap loose/off)
P0460 Fuel Level Sensor Circuit Malfunction P0461 Fuel Level
Sensor Circuit Range/Performance
P0462 Fuel Level Sensor Circuit Low Input
P0463 Fuel Level Sensor Circuit High Input
P0464 Fuel Level Sensor Circuit Intermittent
P0465 Purge Flow Sensor Circuit Malfunction
P0466 Purge Flow Sensor Circuit Range/Performance
P0467 Purge Flow Sensor Circuit Low Input
P0468 Purge Flow Sensor Circuit High Input
P0469 Purge Flow Sensor Circuit Intermittent

You can try cutting a rubber gasket for the purge valve clamp up front. Noise transmission or harmonics (which this is not) are usually cured by moving the critical frequency out of the sympathetic or audible range. NVH engineering is a whole science of it's own.

Maybe Benz got it wrong on Cabrio's but I would like to understand why. It should be fixable. Something as simple as changing the pipe ID somewhere along the way might kill it.

I have reflected on the cars that I have had open at the back. Mainly V6 S Class, E Class & many W203 sedans (on which the W209 is based). None of them transmit the purge valve noise like in your clip to the rear stationary at idle which is I presume how you recorded that. I have taken an engine stethescope to my Coupe & can clearly hear the flutter of the purge valve up front. I do not want to take out the rear seat but lying in the back with a stethescope I can't pick up the purge valve. All our vehicles are of course right hand drive so a driver might hear things a little differently.

If the worst comes to the worst I guess you could place some Dynamat under the back seat so you can't hear it.

mecca281

So based on your response you don't expect the noise to be or to cause any major problems?
I would hate for it to be originating from the tank... Maybe some particles getting drawn up into the filter or pump causing cavitation or hammering somewhere?

Glyn M Ruck

No ~ I don't expect it to cause any problems at all. Only irritation.

If the purge valve leaked it would throw a fuel trim code. Even with the noisiest of old purge valves I have never seen this happen. The purge system is operating on the air/vapour space above the fuel level. The only time it could see raw fuel is if you overfill the tank & saturate the carbon cannister.

Glyn M Ruck

One problem with the W209 is that over it's life it has been fitted with every gasoline & diesel engine in the range other than the V12. A number of generations of manual transmission, the 722.6 & 722.9 auto transmissions etc.

The Cabrio's were mainly assembled by Karmann.

This is a recipe for an NVH slip up on one of the configurations.

Rudeney

Hmm, that almost sounds like a challenge! Actually, the other day, I got this wild hair that I wanted a Maybach. I found a few on eBay for under 6 figures. Maybe I'll wait a year or two and look again. I just love that V12 engine!

Glyn M Ruck

Yeah. The V12 is special. The Maybach is a wonderful car. I just can't live with the styling. Never liked it.

mecca281

Update: I finally decided to take a look at the fuel pump and delivery system.

I got everything open and took both of them out. Below is the fuel pump (pic 1)

While taking out the device on the rear passenger side I opted to cut the fuel line after prying at it for over 30mins.. While cutting... I think I cut the blue and black wire as shown below...(pic2) I was trying to be very careful but noticed that they were cut after the fact... I'm not entirely sure if they weren't cut in the first place.

They seem to be connected to the level sensor, could this have been cut before I got to it and would it cause the problems I was having? I mean there IS another level float on the other tank half with the fuel pump so i would assume my fuel system would still function. Would the cut wires render the whole system non functional?

Also another question.. Now I have everything out and open I am trying to do some spring cleaning... Can I use crc electrical cleaner in the fuel pump??

Another question... What is this pouch is this something I can clean/replace? Pic 4

Final question: is it possible to purchase just the sensor and wiring by itself off the pump (pic 5)

Glyn M Ruck

The thin wires are the level sensor/CANBus wires IIRC. They are required for proper operation. Reconnect them properly. The car takes the input from both level sensors & averages them for gauge display. Wiring configuration changed a number of times on W203/W209.

CRC electrical cleaner is fine for cleaning the pump.

The pouch is the in-tank fuel filter. Your car obviously does not have the round external filter bolted behind the tank. The in-tank filter has a service interval of 120K miles. Twice that of the external filter.

How you can buy the spares is market dependent. In some markets you can only buy the LHS level assembly with or without the pump. In other markets you can buy a few more bits separately. You should be able to buy the filter pouch separately but you will have to check with a dealer or parts supplier.

Older external filter.



Newer in-tank complete assembly.

mecca281

Wow... I have been looking for the cable/harness for the fuel level sensor off the fuel pump and delivery, everyone I have seen sells the whole assembly with the wiring. This is ridiculous since the wires detach from the pump pretty easily.

I tried to pull the old pins and rewire the black and blue cables, but the pin connector fell to sh*t after I finally pried it free from the connector piece.

First off.. Do you know where I can get just the wires or even just the connector head or just the two pins??
It seems ridiculous to pay $300+ for 2 cut wires to a level sensor.

Secondly... I purchased some other blade type female pins and I planed to rewire and use those instead.. They are aluminum... Is that a problem, and also I am pretty worried about rewiring since the plug is actually INSIDE the tank and makes contact with the fuel!!! Is this dangerous? What happens of I get a spark??

There are lots of contacts in there that clearly touch the fuel.. How safe is it (I'm guessing it's an intrinsic system?)

Glyn M Ruck

Benz does not sell the wiring or plugs separately ~ wreckers yard is a possible alternative.

Aluminium connectors are OK. Low voltage signal lines etc. in the fuel tank are safe because the air fuel ratio is always too rich for ignition. It's while you are messing around with things open that a spark could cause a fire. Work with a fire extinguisher at hand.

mecca281

I did away with the connector head, clipped the orange and brown wire, then crimped on new connector pins on all 4 wires and plugged each wire individually.

My level seems to be reading right, I was on E before the repair and added a gallon, which showed up on the gauge,

One major problem... the car wont start! it just cranks but doesnt start.. I figured it was lack of pressure in the fuel lines, so i poured fuel directly into the sending unit.. still nothing... i still have very little fuel in my tank... is there a procedure for starting after loss of pressure in the fuel lines?

mecca281

oh on another note... i dont know if this was the cause of my initial vibration that started this whole ordeal... but when looking at the wires in the fuel sending unit i noticed burn marks on the bottom of the connector plug

I'm hoping to get the car to start and then maybe later purchase a new sending unit.

Glyn M Ruck

We have seen signs of burn marks before.

For start the pump needs to be submerged in fuel. The pump should start & bring the ring main pressure up to 55 psi & then stop awaiting crank. Check your fuel pressure at the Schrader valve on the front fuel rail that connects the injectors. s/b > 55psi or 3.8bar while cranking.

I suspect your fuel level is too low on that side of the tank.

mecca281

Car still won't start. Fuse no4 20A keeps blowing (fuel pump fuse)

I wonder if I blew the pump relay while trying to start the car with a dry pump. Is there a way to visually check?

Glyn M Ruck

If your wiring is correct it sounds like the fuel pump is a dead short.

mecca281

Could it have anything to do with me cutting the plastic pin connector and wiring each pin individually? I'm assuming the red and brown wires are power supply for the delivery unit..

I'm gonna test the relay today to make sure it's still working... Something tells me it is not the problem.