I just picked up my dream car, 1986 300SDL, 180K miles, grey with black interior - yeah!

It has a number of gremlins - the question for now is: the recirculating air valve attached to the turbo (137b) is not connected to the vacuum transducer (Y31). The transducer had just an open hose on the "out" fitting.

I would have connected it to the air valve, but there is no fitting on it as is shown in the diagram. This diagram is for the 87, so I'm assuming its the same for my 86.

There is a fitting off the side of the air valve that connects somewhere else on the turbo/exhaust (and does not appear to be the right type of connection for the air valve in any case).

Is this some sort of modification? Should I just plug the "out" fitting on the transducer? To what effect?

thanks!

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The turbos used in the 86 and 87 SDL were different. The main difference being that the turbo in the 86 doesn't have an ARV, that's why your car doesn't have the appropriate plumbing. Sounds like the PO installed an 87 turbo in your car at some point.

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Serenity-86' 300SDL 482,000 miles (on a "14" head!)

Thanks for replying!

so what do I do with the "out" fitting on the vacuum transducer (Y31)? Leave it open or plug it?

Check out my link of a few days ago with photos and replies.
603.xxx Vacuum Work - What are These?

I was wondering the same. What I did was put a bb in each of the two vac lines passenger side bound coming from the 5-way connector above the Vacuum pump. On my SDL there is also a heavier black line (plastic, and filter) grouped with the mentioned vac lines which apparently threads to the cabin for fresh air to the valve. That line I just left alone. I had suspected vacum leaks in either the ARV, ERG, or connectors.

I may be off base...who knows but at least you can see the photos and member's ideas. Runs very well now.

robcarsonjr

that's very helpful, thanks. How did it run before? Mine is very sluggish!

I'd be happy to take a look at it. My bet is the turbo is not spooling up. My car is a little doggy below 2,000 rpms but then sling shots on out when the turbo kicks. Best of all it is free!

Read about "cleaning banjo bolts", "vacum line", and "overboost limiter" switch + bypass.

As you probably already know you will want to tune up the fuel system too. New fuel filters are only a few bucks. Do a "hot shot" cleaning of your injectors by filling the canister fuel filter with Diesel Purge and running that through.

You are going to love that car. Some where I have a great write up that is so true. Give me a few minutes and I'll copy and paste it into another PM.

Rob