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There is nothing to be connected here, it is a just vent line. These versions dont have the entire housing under vacuum.
Just an FYI, on earlier models it went here.
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83 280 SL- 5 speed-The PIG
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An 84 380SL WUR venting to atmosphere?
I'm no expert....but it should be venting back into the crankcase vent or something else with passive vacuum.
And that electrical harness on the WUR needs looking at. No 12V to the WUR and you'll experience some problems.
I'm no expert....but it should be venting back into the crankcase vent or something else with passive vacuum.
And that electrical harness on the WUR needs looking at. No 12V to the WUR and you'll experience some problems.
My '85 380SL is the same, I think they all had this type from 1982 onwards.
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1992 Mercedes 400E 124.034 1986 Mercedes 560 SEC 126.045, M117.968
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if the heater is still good I have taken them apart and cleaned them. The WUR is basically a controlled leak to the return side of the fuel system. A lot of times they become clogged and don’t allow fuel to pass when cold. I also drill and tap the pivot pin and install a bolt and washer. Then with a fuel gage hooked up I dial in the pressure based on the ambi temperature and pressure on the graph. Then alter slightly to get no flat spots on throttle snap.
Sould have a nylon vacuum pipe going in to the rubber elbow .
Number 3 Needs vacuum from inlet manifold .
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Not for a US spec 1984 380SL, these are different from the earlier (pre-'82) ones and the non-US spec cars. It is a vent to atmosphere.
After that would put things right,, i saw a picture of a wur with no nylon pipe going to inlet manifold i just thought it was missing .So with the pipe it takes in ambient air pressure .So how will poster know which one he has on his engine?
If it is a US car, then it should be open to the atmosphere, simple.
It is just as simple as you think. There will be minimal fuel spill.
The WUR is a "dumb" device that works from a 12 volt source heating a bi-metal that alters the output "control pressure" getting to the top chamber of the FD (Fuel Distributor).
The system pressure lives in the bottom chamber of the fuel distributor. The control pressure lives in the top chamber of the fuel distributor and is controlled by the WUR. The fuel metering plunger lives between the two pressures in its own silo like chamber.
When you first start the engine the WUR provides low fuel pressure to the top chamber (top of the fuel metering plunger) which allows the fuel metering plunger to ride higher in it's chamber thus allowing more of the fuel metering slots to be exposed which results in a mixture enrichment. As the WUR bi-metal heats from the 12 volts supplied to the WUR it slowly raises the "control pressure" (pressure in the top chamber) which forces the fuel metering plunger lower in it's chamber thus exposing less of the fuel metering slots which in turn makes the mixture leaner.
If you suspect the WUR then your first step should have been to check the control pressure. If the WUR is doing its job, then on initial start from cold, the control pressure should be around 20 psi. As the WUR heats (not the engine but the bi-metal in the WUR) it increases the control pressure to somewhere in the area of 50 psi (maybe even 60psi). If those are the results you get when checking the control pressure (checked at the top of the FD) then the WUR is doing it's job and need not be replaced.
The WUR is not to be confused with the cold start valve which is actually just a 9th injector that pours raw gas into the intake when the engine coolant temperature is below a certain value.
Before you start changing more parts, check the system pressure and the control pressure. If you need advice on how to do that just ask... there are many here who will show you how. If both the system pressure and the control pressure check out then it's time to look elsewhere for your problem. There are many things that can cause your symptoms, so we need to take each one in it's turn.
The system pressure lives in the bottom chamber of the fuel distributor. The control pressure lives in the top chamber of the fuel distributor and is controlled by the WUR. The fuel metering plunger lives between the two pressures in its own silo like chamber.
When you first start the engine the WUR provides low fuel pressure to the top chamber (top of the fuel metering plunger) which allows the fuel metering plunger to ride higher in it's chamber thus allowing more of the fuel metering slots to be exposed which results in a mixture enrichment. As the WUR bi-metal heats from the 12 volts supplied to the WUR it slowly raises the "control pressure" (pressure in the top chamber) which forces the fuel metering plunger lower in it's chamber thus exposing less of the fuel metering slots which in turn makes the mixture leaner.
If you suspect the WUR then your first step should have been to check the control pressure. If the WUR is doing its job, then on initial start from cold, the control pressure should be around 20 psi. As the WUR heats (not the engine but the bi-metal in the WUR) it increases the control pressure to somewhere in the area of 50 psi (maybe even 60psi). If those are the results you get when checking the control pressure (checked at the top of the FD) then the WUR is doing it's job and need not be replaced.
The WUR is not to be confused with the cold start valve which is actually just a 9th injector that pours raw gas into the intake when the engine coolant temperature is below a certain value.
Before you start changing more parts, check the system pressure and the control pressure. If you need advice on how to do that just ask... there are many here who will show you how. If both the system pressure and the control pressure check out then it's time to look elsewhere for your problem. There are many things that can cause your symptoms, so we need to take each one in it's turn.
83 280 SL- 5 speed-The PIG
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