My 83 380 SEL has always had a stange start-up fault, which my indy says is a faulty warm-up compensator. (when stone cold it will idle very slowly then stumble and die for about the first minute, then the idle will smooth out, settle down at 650 rpms and run perfectly)

I bought a used replacement but it has different vacuum connections than the one in it now (see photos). Which is right and what goes where?

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

When you buy parts, you need to buy the correct part #. I would think the original one was the correct one if their is only one 1 vacuum hose leading to the WUR.

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Question Authority before it Questions you.

You can try a science experiment by plugging the large outlet on the replacement and routing the line to the small one.

But try this with your existing one. Remove the larger fuel line fitting and use a pick to carefully fish out the mesh filter beneath it. Disassemble the filter into its four layers and clean each one with throttle body cleaner. You need to look closely to be sure all the crud is gone. Reassemble, reinstall, and see if that makes a difference.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

I had removed the old one and sprayed a ton of throttle body cleaner in there. Some crud did wash out. Not good enough?

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

No, you need to take the screen out, take it apart and be sure each layer is clean.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

How hard can I pick at it without damage? I used a dental pick but it seems like it's in there pretty solid.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

You need some force. Poke around the edges with a pick. If you put a hole in it getting it out, you can arrange the layers so the hole doesn't go straight through.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

Yep, that worked. I removed a total of 5 screens. The ones on top and bottom were relatively coarse. The layers above the bottom one and below the top one were finer, and the one sandwiched in the middle was very, very fine. Almost like steel nylon stocking fine.

I soaked them in cleaner for a few minutes, then used a spray can of it to blow through each screen from both sides. When I was done they looked very clean.

I had to wait until this morning to see if it made a difference, as the car needs to be stone cold to exhibit the symptoms. The cleaning did seem to make a difference. Instead of dropping to minimal rpms with repeated stumbling and stalling for a minute or more, it dropped to a couple hundred rpms, didn't stall, then stabilized to a normal idle in about 15 seconds.

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2000 Mercedes S500
1990 Mercedes 560SEL
1970 Triumph Spitfire

Hey everyone,

I'm just now getting into my WUR('82 380sel). I found some vacuum issues maybe.

1) Where the vacuum lines split one goes to the front bottom WUR and the other goes to an inlet split into the top of the intake manifold, I found a cracked hard line that was leaking and fixed that.
2) Checked the vacuum on the big one on the bottom facing towards the back, ok.
3) Where does the one on top of the WUR connect to? Mine has a little rubber elbow vacuum line fitted and it doesn't connect to anything. I look all over for a connection nothing. Is it just a vent? I put my MityVAc on it and it wont hold a vacuum very long it leaks off real slow.

Thanks for any help,
Bobby

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Bobby
'82 380SEL
'98 E320W<--Rusty

The fitting on top is a vent.

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Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe

ctaylor738,

Thank you,
Bobby

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Bobby
'82 380SEL
'98 E320W<--Rusty