I was getting some odd codes on my 96 C280 - p0400 and p0411, and traced it down to a broken vacuum feed line that feeds the sov. The feed line was completely missing - obviously the problem.

But here's what complicates the situation - the last time the car was in the shop my mechanic said he 'replaced a bad vacuum line'. I have no idea which line it was - but I suspect he caused a problem.

The problem is this. There are three vacuum ports on the intake manifold. Working from the front of the car to the to the back:
#1 appears to connect to something under/near or on the ABS
#2 connects to the component in the photo below.
#3 - the rear-most vacuum port is the problem. upon inspecting a friend's C280 I noticed on his car it connects to the sov. on my car it connects under the 'arch' to something I can feel,. but not see - just 1/2" to the right of a wiring harness that is parallel to the air intake that runs across the top of the engine.

My question - is that #3 port supposed to feed the sov? and if so, why did my mechanic hook it up to this other component? What vacuum line is supposed to hook to this mystery component I can't see, and where is that missing feed located?????

Attached Thumbnails

 

the picture is your fuel pressure regulator...




I don't have any further data to offer on what your mechanic did.

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