charon_sin - 9/20/2007 5:46 PM

If you need a new regulator replace it with this http://www.unwiredtools.com/utcis.html

bram_r - 9/23/2007 3:28 AM
I will disassembly this regulator today, but based on EPC pics and this article makes me think my connections 3 and 4 are swapped. Maybe someone can confirm this by checking connections on their 280GE (or 230GE for that matter). A little hard to visibly check, but by feeling you should be able to know what connection is going where.

greetings,

Bram

bram_r - 9/23/2007 6:54 PM
By the way, your side connection comes out the right side where mine is coming out left side. I think it is the same valve, but there is a boss on both sides of lower part of this valve. Just a matter of where you tap in the tube.

Bram

bram_r - 9/24/2007 3:26 AM

Hi DesertStar, Bernie,

thanks for the replies, always interesting to discover 'the little differences' and trying to argue if a book is really right or not.

I'm pretty sure that the top connection of the WUR should lead to a (high) vacuum connection in the inlet manifold. As can be seen in one of my green coloured EPC prints, my WUR top connection (now) leads to the bottom of the inlet manifold.
Here you'd have the same vacuum signal as is going to the brake assist (vacuum connection on the inner fender side of the inlet manifold).
In idle or cruising/downhill situations there would be a high vacuum since the throttle valve is almost closed. Then, with also vacuum in the top chamber of the WUR (and atmospheric pressure in lower chamber), the regulating/signal pressure will increase and the mixture will lean out (as it should). In the official MB G-manual there is even a chart how much your regulating/signal pressure should be at what vacuum. I can post it here so you can verify, if you want to.

So Bernie's connection 'X' should be a vacuum connection. My question however is where does it get its vacuum signal from, in front of, or after the throttle valve. If connected in front of the throttle valve, you'd be having your air inlet pressure (only your pressure drop over your air filter and maybe your K-Jetronic air meter disc), which will only be a slight vacuum in high rpm situations. Maybe you can check again where your top 'x' connection is going to?

The side inlet is something to have some thoughts about.
Normally, you'd like a carb jet size to be smaller with altitude increase, so with the thinner air, you'd still be having the same mixture as on sea level. So, as also with our MB WUR, we would like to see a leaner mixture with altitude increase. The funny thing is if you look at fig. 30; if the lower chamber (connected to atmospheric pressure) is having a lower atmospheric pressure, the spring force of inner spring will be reduced and so reduce the signal/regulating pressure and thus richening the mixture.
This can't be the way Robert Bosch designed this thing and I'm pretty sure he's a bit ahead of my knowledge level as it comes to fuel injection.

When connecting this side inlet somewhere to your air inlet somewhere (where a little vacuum is created in wide open throttle situations) you'd be having your WOT enrichment following the same route as stated above (low signal pressure => rich mixture). But now we do get the enrichment, which is what we want at wide open throttle.

However, this whole WUR thing is a constant balance between inlet manifold pressure on the top and some pressure in the bottom. In a wide open throttle situation, your inlet manifold vacuum will also be pretty low and I'm also not exactly sure how much inlet manifold pressure/vacuum will be different in high altitude situations, so my thoughts above leaving the top chamber vacuum constant and only the bottom chamber pressure altering in not completely right I guess. Also, how much vacuum is present at what part of the air inlet is also something I'm not a full 100% on.

Bram

elevatorbernie - 9/22/2007 6:08 PM

Have you tried it? I want one, where did you buy it? :cheers: