How to disable the BFS and other vacuum lines?
 

Hello MBZ fellas..
I am trying to disable to vacuum transducer, aka BFS. Others stated it is easy, just locate the line going to the transmission and connect it to the IP. But What I am looking at are a bunch of other vacuum lines.
What do you do with them?
I also post the picture of the BFS and other lines that I labled.
Could someone please identify them for me?
If someone could tell me which line I need to disconnect and connect to disable the BFS. I labled the lines for the ease of identification.
BTW, this is a 1987 300D

Attachment 98898

Line F is the boost signal line which feeds the ALDA and BFS, the BFS through line D. Line F should go through the VSV beside the windshile washer bottle. Line E is the vacuum signal from the VCV to the BFS. To disable the BFS, route Line E directly to the transmission modulator. You only need one of the green cylinders. Items A, B and C are no longer needed. There is a splitter at the VCV vacuum source. Vacuum from the engine vacuum pump feeds both the VCV and BFS. If you disable the BFS, cap the vacuum source line to the BFS so the VCV receives proper source vacuum.

This thread will explain why this is fresh in my mind - http://www.peachparts.com/shopforum/diesel-discussion/310597-fuel-leaks-4-injector-hard-line.html

Sixto
87 300D

Thanks so much... this is easy now with your instructions. Mega thanks

The BFS is now disable... thanks for the info sixto

How does it shift?

Sixto
87 300D

A little better since I disabled the BFS. I also adjusted the modulator to have it shift nicely. Thanks a million.

Can I ask why disabling the BFS is desired in this situation? I have harsh shifts and I know I need to check vacuum at the booster to see if the vacuum pump is working, but, I am not sure how to check the BFS, or, if I should consider getting rid of it as described here.
I did adjust the modulator to 46psi (722.321) at the diagnostic pressure port. It was at 66psi and this helped but shifts are still pretty rough. My vac line coming from the engine only seems to supply about 5Hg to the modulator. This seems low to me. Car is a 1986 300SDL. Hope I am not thread jacking since your problem seems to have been solved!

You have a different problem if the VCV provides only 5"Hg to the BFS. Removing the BFS won't help. You need to determine whether you can adjust the VCV to put out 12-15"Hg at idle or it's time for a new VCV. What's the vacuum reading into the VCV?

Sixto
87 300D

I will try and get that tonight. I ran out of time yesterday to get all my checks done.

So I measured vacuum at the brake booster and I have 24in Hg. That should be good, right?. When I measure the line directly on top of the BFS, I get 3in Hg and it climbs so slowly you can almost not see it. I measured the port for the modulator (not the line) coming out of the BFS on top, and, I get the same 3in+ Hg. There is a line coming out of the VCV that is directly on the side of it and it was capped. I measured there and nothing; 0in Hg. I tried several other vacuum points and got nothing. I am not sure what else to try but I am beginning to wonder if it is the VCV itself.

Measure vacuum at the small fitting on the engine vacuum pump, then using the first link in this post as a reference - http://www.peachparts.com/shopforum/diesel-discussion/105297-vacuum-diagrams.html - measure the vacuum at 61a. There shouldn't be more than a 1"Hg drop. If there is more of a drop, cap the other fingers of the 5-way connector off 62 and find the leak.

Sixto
87 300D

Hi Foolio, I needed to disable my BFS because one of the nipples was broken at the bottom of the BFS and I don't want to pay over $200.00 for it, that is if you can find one.