My fuel pressure regulator on my 88 300E has a vacuum line coming out of it. I bought the car used and the vacuum line is disconected. Does anybody know where it connects to? Thanks for any help.

On my 190E the Vacuum line connects between the egr valve and the idle speed control valve.

I do not think that there is an EGR valve on mine, but I am not sure.

Come on guys, somebody has to know where the vacuum connects.

If it is what I think it is, the line from the regulator goes up to the black rubber hose that connects between the air cleaner housing and the crankcase breather.

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Ron Miller

1986 300E

Thanks people, but I thought that this is a vacuum hose and should be connected to some sort of vacuum source such as intake manifold or something. This rubber connection between the air cleaner and camshaft cover is not a vacuum source. I do not doubt that it may connect there, I am just curious as to why...

On the 190E this hose is connected to a vacuum source which is the idle speed control valve. The back end of the idle speed control valve is connected to a vacuum source and I think it is called auxillary air device (basically a vacuum pump)

On my 300SL-24 the vacuum line coming out of the fuel pressure regulaotor hooks up to a black hose that links the air-filter box to the valve cover as well.