EGR not connected
 

1986 420SEL
The vacuum line coming off the EGR valve is crimped closed and is not hooked up to anything. I tried to find the vacuum control valve (see attachment - #90) but I am unable to find it. What does it look like and where is it? Thanks!

EGR is 100% an emission item.

Will not cause any RUNNING issue if disconnected.

If you pull vacuum on the valve with the engine at idle does the engine run rough?

I don't know. I'll give it a try. More than that, I was concerned that the vacuum control valve had an open connection. I was unable to find the device at all. What does it look like?

The therno-vacuum valve (#79) is on the front of the intake manifold.

If emissions are not an issue where you live, get rid of the entire system.
If you ever remove the intake manifold you'll know why. Hot oily exhaust fumes condense in the cool intake passages. This creats "coke". It's a bear to remove. After a 100k you won't believe how much is in there.

But where is #90?

Will "Seafoam" remove it? :-)

Never tried Seaform. I used long wire brushes and many, many cans of carb cleaner. #90 as I recall was located on the left front inner fender. #79 looks like a typical sending unit. It lives on the top front of the intake manifold. You will need to plug the vac ports on the throttle body. It lives down in the front of the intake manifold. I used vacuum caps. Just follow the vac tubes. I had mine off to replace the donuts so it was easy.
I found metric plugs for #79 and the exhaust manifold at a place that makes hydralic hoses. Unlike American cars they are not tapered pipe threads. Thery're straight threads. On your diagram just above #60, you will need to fab a blank-off plate. I used 1/8" aluminum, easy to work.
This system poisons an engine.

Only thing I do not like is using vacuum plugs on the throttle body, they can become hard/brittle pretty quick. I just cut off those brass tits, counter sink the holes, and fill with epoxy. That way I know I will not have to deal with a vacuum leak there again.

Hell, I think there were five hoses coming off that on the 560. Insane really. Just removing the AIR injection crap drastically cleans up the engine. I have not made the EGR block off plate yet, but I plan to do just as 'DAVECAD' mentioned. When I had the intake off my 280,000 mile 300SEL it was FULL of EGR grossness and the fitting from the EGR pipe to the intake plenum was blocked by EGR crap... the system was not functioning and the car passed emissions without it. I fully removed it all when I did the top end here recently and the car passed the smog test big time.

I left parts 79 on the intake manifold, I just removed the red top so now they just appear to be brass plugs. :) The rest of the nonsense on the inner fender/splash guard area can just be disconnected and removed. I would venture to say there is nearly 20' of tubing once all removed. It is shocking.



All you really need is the vacuum reference to the EZL module.

I cannot wait to install my regular Euro true dual manifolds and eliminate that precat right by the firewall. I am starting to wonder if that precat is a main contributor to the head gasket issues the M116/7 face on that pass side. :confused: