Hi all!

I have a question about my 1985 500 SEC. On the front of the motor, just to the left of the idle control valve, is a unit, i dont know what it is, maybe a fuel accumulator, or regulator, it has fuel lines going to it, it also has a little vacuum line coming from the top, but the vacuum line is missing. I do not see any loose vacuum lines, and when i attach a vacuum line to it, the idle noticably changes, so it must be important! Sorry for my lack of knowledge, but i am new to mercedes motors. If anyone can tell me what this unit is, and also where the vacuum line for this unit is suppose to come from, i would really appreciate it! Any help i can get would be great!

Thanks again!

Does the unit you are looking at look anything like the items in these pictures?





If so you can find a little more info on the hook-up in the 560SEL Accomplishments thread, buried somehwere around page 4 or 5. The hook-up for a 500 ought to be similar.

Hope this helps.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Hi Mike,

Thanks for the pictures, my motor is a little different, but the unit im talking about is a metal unit to the left of the idle control valve. In your pictures it would be where all those vacuum hoses are protruding from, right next to the idle control valve, but there are only two coming from the top of my unit.

Thanks again for the pics!

If anyone can tell me what vacuum line is suppose to connect to this unit, as i am pulling my hair out, and i think this vacuum is contributing to my rough idle. It is something to do will the fuel, as there are fuel lines going in and coming out, but on the top, is a vacuum boot for a vacuum line, but the line is missing, and i do not see any loose vaccum lines. If anyone can help i would really appreciate it!

Those are all vacuum lines in that area, shouldn't be any fuel lines.

On the radiator support you should have a silver sticker, about the size of a 3x5 card that should have the vacuu line routing diagram. The area just to the left of the idle valve, where the vacuum lines connect, those are thermo switches for routing the vacuum and should have a nipple or nipples (for connecting the vac line) coming off the top.

You may find that one, or more, of the lines has come loose and may have to replace it. You may also find that the other end of the line connects under the intake manifold. The lines under the intake can be replaced without pulling the intake if you have a long set of needlenose pliers.

Look for the diagram, if yours is gone or unreadable, I can look on my CD for the 500's diagram this evening.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Thanks Mike, i'll take a look for the diagram, and let you know! I appreciate it! I dont know what it is, but it does have a fuel line coming into it, and one that goes out of it to the fuel distributor, also, an electrical connector, and one vacuum nipple. When i turn the ignition, it makes noise, like a clicking sound. I have no idea what the hell the thing is, but when vacuum is applied to it, it noticably changes the idle. It does not look like the photo you provided, with all the vacuum lines. At first i thought it had two vacuum connections, but it has only one, the other is the electrical connector. Thanks again for all your help Mike! If you could also let me know what you think this thing is, that would be great!

I'll check the manual when I get home from work. I'm getting to play boss this week, so I'm mostly desk bound (what a PITA), but it allows me to poke around here .

If you could post a picture of this device, it would help in ID'ing it.

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Thanks Mike,

I'll get a picture tonight and post it for you! I have to try and find a CD for this car for myself! Thanks again for all your help!

Yes, a picture will definitely help. I poured over the manual this afternoon and still cannot determine just what you are describing. The only fuel line that comes close to the area I can think of is the steel line from the fuel distributor to the cold start valve (which also has an electrical connection). The cold start valve is at the lower right corner of the bottom picture I posted.

I did find the vacuum diagram for your car in the manual under the 500SEC files, but it is the same diagram as for the 5.6L engine. There is a vacuum line that crosses through the area on it's way under the intake, but does not connect in that area.

Standing by for pictures (or someone with a 5L) .

__________________
Mike Tangas
'73 280SEL 4.5 (9/72)- RIP
Only 8,173 units built from 5/71 thru 11/72

'02 CLK320 Cabriolet - wifey's mid-life crisis

2012 VW Jetta Sportwagon TDI...at least its a diesel

Non illegitemae carborundum.

Hi mike!

Sorry I took so long, my digital camera is broken and i cant find anyone who has one, but i did find out what that unit is, its the warm up regulator. Still no luck finding the missing vacuum line. There are a couple of vacuum line attachments on this unit, but only one on the top next to the electrical connection. The one on the top is the one thats missing a vacuum line. If you know where the vacuum line for this is supposed to come from i would really appreciate it!

Again, thanks for all your help Mike!