EGR blocking plate kit - Page 12 - PeachParts Mercedes-Benz Forum

ck42 · #**166** 04-17-2005, 09:24 PM

It looks like maybe the entire vacuum converter (#84) can be removed. On my '85, this thing sits directly in front of the coolant fill tank.

Also, looking at the pdf for the EGR section, it appears that the entire EGR operation to control that single vacuum line to the EGR valve is snaked all over the place! valves here and there...temp switches, rod sensors, etc, etc..... I think if we got down to it, we could remove a LOT of the vacuum lines under the hood and maybe a box full of misc parts.

Chris
'85 300SD

Hit Man X · #**167** 04-17-2005, 10:27 PM

Interesting to say the least! I recall somewhere that our vehicle also uses some of those bits to control the ol' 722 trans, that's why I've yet to install it.

Johnhef · #**168** 04-18-2005, 12:10 AM

Quote:

Originally Posted by ck42

correction on the leaking hose(s). Looked again and there's just a single large diameter hose under there....and it's weeping.

Chris
'85 300SD

you said it was only a few inches long, its not your bypass hose is it?

I'd replace it asap if it is. I lucked out and mine blew right after work one day and we stocked the hose.

ck42 · #**169** 04-18-2005, 07:27 AM

Not sure if it is.....I have pix I've taken of the area and will post one when I get a chance tonight.

Chris
'85 300SD

jsp · #**170** 04-18-2005, 01:17 PM

Quote:

Originally Posted by Hit Man X

From the pic you posted... it appears I can remove the EGR valve, the vac line to 84 "Vac Converter"

What about this "Air Recirculating Valve" No 71 to "Switchover Valve" No 81?

Basically trying to get the last word on the '85 Fed/'85 Cali's...

Here's my overall conclusion to the whole question of what to remove to make life simpler under the hood:

1. A lot of vacuum stuff directly related to the egr and arv is all over the place; I've taken them all out and capped up the vacuum system as far upstream as possible.

2. Items eliminated include the black box on top of the valve cover (my '82 300T-D; my Cali '84 300D-T doesn't have this), and everything downstream of it.

3. It seems that on some models, this black box also contains valves connected to the accelerator linkage, and therefore controls transmission smoothing. Even on my '84 Cali which does not have the black box, a careful study of the vacuum diagrams (see posts above) leaves open the possibility that, black box or not, egr-related vacuum is related to transmission modulation.

4. However, as at least one or two others have posted above, getting rid of this junk and capping off the vacuum as upstream as possible lessens the likelihood of leaks in the system overall. The probable result (not 100% sure on my 84 Cali) is that the transmission modulation gets full vacuum, regardless of accelerator position. For me, this has resulted in a noticeable improvement in shifting. I guess the logical downside is that at high engine speed, when not as much vacuum is needed, the modulator gets full vacuum anyway, theoretically leading to unnecessary softness (?). But I have not noticed this problem.

So, this is my practical solution. To recap, I've taken out everything egr/arv related downstream of #c below. I've also capped off the accompanying black vacuum return lines.

a. main trunk (thick line) from vacuum pump to brake booster
b. one of two thinner lines branching off from this main trunk
c. point at which #2 branches off into about three or four different places, including egr, arv, trans mod., etc.

-------------------
p.s. I've also removed cruise control with its accompanying linkages, since I never use cruise control, and it doesn't work.

Hit Man X · #**171** 04-18-2005, 04:10 PM

I'm trying to absorb, and am comparing pics to '84 Fed vs '85 Fed. I barely recall my '84 Fed 300D.

Happen to have any pics of what ya did?

#**172** 04-18-2005, 07:00 PM

Just installed my "kit" on my 190DT. Only problem was getting the round copper fitting onto the exhaust manifold. First, followed directions, but I could not get the clamp to close around the copper circle. It was a bit too big. I worked on it and worked on it (crimping it once), but finally got it to fit. Problem is that it was a bit too "thick" for the clamp--I couldn't get the clamp squeezed enough to start the bolt without cross-threading.

I finally took the clamp and rasped out the hole so that I could start the bolt without cross-threading.

Otherwise, no problem. And the car seems good with the kit in place.

Thanks

Brian Carlton · #**173** 04-18-2005, 07:45 PM

Yep, it's a PITA all right. I've done it about 15 times and it still takes me 10 minutes, with a couple of failures, until I get it.

The only way to do it is to use a set of channel lock pliers to really pull the clamp closed before you start the bolt.

Of course, sometimes the pliers slip off the edge of the clamp and you have to start all over.

ck42 · #**174** 04-18-2005, 09:01 PM

Ok....got the pix...I think

Where the arrow is pointed....that's where I see the weeping.
Click on image to enlarge picture.

Also...what is that blue/red hose for?

Hit Man X · #**175** 04-18-2005, 09:08 PM

That red/blue is more emission I believe... or what I'm trying to find out at least.

Looks like you need to take a screwdriver to a hoseclamp... I can't tell but looks like a coolant leak. It's dark here and I don't feel like going out to examine my auto in my underpants.

Edit... for the sake of science I will in a bit.

Johnhef · #**176** 04-18-2005, 09:10 PM

thats definitly your bypass hose, I'd get on it soon.

the line youre referring to goes to the air recirc valve, according to above posts you can remove the line and cap it off now.

Hit Man X · #**177** 04-18-2005, 09:17 PM

Just got back in from looking about...

Runs from the H2O pump to the thermostat it appears... yeah a leak there is no bueno.

ck42 · #**178** 04-18-2005, 09:24 PM

Thanks guys for the help!

I'll try the easiest things first. I'll make sure the clamp is tight and then watch for continued wetness there.

As for the ARV...I've seen it mentioned quite a bit but am unsure as to its function. What does the ARV do? By virtue of its name...it almost sounds like it would do the same thing as the EGR.

Instead of recirculating exhaust gases, does the ARV inject air into the system?

[edit]

Brian....maybe we need a blocking plate for the ARV now

Chris
'85 300SD

ck42 · #**179** 04-18-2005, 10:04 PM

On to this contraption:

This is in front of the coolant tank where the EGR and ARV tubes ended.

Somehow the ARV tube has been disconnected in the last few minutes....not sure how that happened

Anyway...is the black line going in that Y's off the main vacuum line to this device?

Any idea of what the blue line at the bottom and the white/orange line are for?
Couldn't track them out in the dark.

Chris
'85 300SD

Brian Carlton · #**180** 04-18-2005, 10:19 PM

Quote:

Originally Posted by ck42

Brian....maybe we need a blocking plate for the ARV now

Chris, I believe the ARV allows the turbo to remain spooled up and it dumps the boost to the exhaust during part throttle. Something to do with emission control.

If you disconnect the vacuum line to the ARV, it cannot function.

That vehicle is soooooooo different than the '84, it's really amazing.