Bad news...
Somehow the wur stoped working...
When checking the voltage arriving to the wur plug, (read 10,5 Volts, car not running), and after plugging it again I noticed the pressure was not rising...
Tested the connectivity and... infinite!

Here is the faulty part:
http://forums.pelicanparts.com/uploa...1613765640.jpg

Tony was right! I should have never touched this wur...
No I realize that I have been searching at the wrong place...
This is really frustrating... what else?!

Mine is:

http://forums.pelicanparts.com/uploa...1613766703.jpg

The 097 is the correct FD. The pressure value difference with and without vacuum is around the .6 you saw when you pulled off the line with the engine running. When you are setting the CCP and WCP you do need to be sure which values you are using. The CCP chart is with vacuum. Getting yourself a mitivac would be helpful. Obviously you need to resolve the power/part issue.

Since I don't have a vacuum WUR on my US '82, I don't have much practical knowledge of its effects, nor a sort of memorized schematic for it (all that extra plumbing). However, for grins I once applied a vacuum to the upper (atmospheric equalizing) port of a WUR. It raised the CP. I applied a vacuum to the lower (unused, in my case) port. It lowered the CP. At least, that is what I remember (which could be backward?).

Why? I supposed it had to do with the barometric diaphragm in the WUR which supports the base of the inner of the two springs (the outer spring base is the WUR case, so doesn't vary).

http://forums.pelicanparts.com/uploa...1613773182.jpg

Vacuum in upper chamber, more pressure upward from the center spring. Vacuum in lower port, less pressure upward from center spring.

This would suggest that, absent other controls in the system, that wide open throttle with a lower port vacuum attachment would have a higher CP (leaner), and idle a lower CP (richer).

With no vacuum application, this barometric diaphragm would provide a measure of altitude compensation.

But theory aside, now that you have people with knowledge of these vacuum systems involved, and you can figure out what is incorrectly connected or not functioning, which is where suspicion is moving here.

And if the heater coil on the bimetalic spring element has quit working (easy to check with an ohmmeter), I believe you can get a replacement, either of it or of the spring with heater.

By the way - your English is perfectly functional, and as grammatically correct as is usual on this forum. Tony is just coaching you on troubleshooting techniques. Besides, about all I know about Portuguese is that the C is soft (at least it is in my friend Goncalves' name).

Clarification......
 

Walt,

The picture of the WUR posted above is NOT the same type of WUR used in SC’s (‘78~’83) whether US, ROW spec. lambda or without lambda. The WUR that Alex has is -089 (vacuum assisted) and totally different in operation and configuration. Two (2) totally different WUR’s. This particular type of WUR was last used in 911 CIS for 1977 models.




Alex,

Your broken WUR-089 just needs a replacement heater. There are two (2) heater resistances used in WUR-089, they are the 30 Ohms (Germany) or 35 Ohms ( France). Your WUR probably has the “Germany” cast on it. The replacement heater/s is available and I just received some from an European seller. Walt’s post is very informative but be aware that your WUR is not the same in operation and configuration.

Tony

Tony - do you by chance have a similar Bosch based diagram of the 089 in your collection?

My impression is that, schematically, there is very little difference between the WURs Porsche used, and, for that matter, other car manufacturers used. The values differed, of course, as did using or not using vacuum. But understanding how the components worked, with due consideration for differences like what vacuum, if any, was employed, allows some cross model understanding when attempting a differential diagnosis.

That is a bit different than knowing very practical things like (wow) the difference between Germany and France resistance heaters.

I have long been interested in just what the differences actually are in the various WURs in terms of the individual parts which affect the values. Some may be just in how they are hooked up. For instance, the one shown puts a vacuum on the upper chamber, but later ones just used that connection as a source of (filtered) atmospheric pressure.

Are the two internal coil springs different between models? The module which holds the springs is screwed into place. Is it different, or is its height setting - how far it is screwed in - different?

Is the barometric diaphragm set up differently between models or is it the same part, with the same air pressure trapped inside its two halves? Or am I wrong in thinking it is like what you find in a barometer, and it is really just a diaphragm separating the upper from lower chambers (which is what the schematic shown looks like), and just adjusts the resultant force of the lower chamber spring and the upper chamber spring? Or did vacuum assist models use just a diaphragm, and non-vacuum models used a concentric ribbed barometric diaphragm?

It is easy to see how Bosch had a way of setting the depth of the two upper steel cylinders when manufacturing a WUR to the specs they and the car company worked out for cold and warm pressures - the same parts could just be set at different depths in the aluminum housing.

I admit to a special interest in this because the '82 US 3.0 I purchased from someone far away did not have the 089 WUR - it had the 033, and I had no reason to think the owner had tinkered with things. Tony pointed out to me that this was the wrong WUR, but its control pressures were correct for an '82 and the engine ran just fine once I hooked up the oxygen sensor system. It had the tube for lower chamber vacuum, but there were no vacuum lines attached.

It wasn't until I got a recording AF meter that I started messing with it. It subsequently was replaced by a shop with the 089 (shop had same reaction - wrong WUR), but in terms of race track AFRs, they still are puzzling. However, I don't recall (car is in storage at the moment) that the 089 uses any vacuum assist - the fuel distributor doesn't have an unused port, and there are none of the extra devices shown in the earlier schematic, and the O2 sensor system .

But it looks like Alex has finally advanced things to where he can check vacuum connections, and perhaps also try to locate possible unmetered air leaks. It makes sense that those would have the most effect on the air fuel mixture at the quite slow RPMs (~300 RPM) created by the starter. Unmetered air leans the mixture. When he blips the throttle after the engine finally starts, it seems to work fine as I recall. Hot start CPs are higher to begin with, and the cold start valve is apt not to be operative.

A search of this forum will provide a lot of information on how one can test for such leaks. Quite recently Tony showed how he made a smoke machine to use for this purpose. Less precise methods involve spraying a flammable substance around the various rubber fittings to see if idle speed increases. Carb and brake cleaner will work for this, as will propane from an unlit torch.

Walt

The last two entries in the linked thread I think explains how it works. Finding a diagram of the internals for WURs is a challenge.

http://forums.pelicanparts.com/porsche-911-technical-forum/117725-lets-connect-wur-right.html

Here's a photo of a 045 WUR showing the underside of the pressure cell and the vacuum connection.
http://forums.pelicanparts.com/uploa...1613922968.JPG

The following two photos show the result of applying vacuum to the port. Note there are two springs. The outer sits on a fixed support, the inner sits on the moveable seat connected to the diaphragm.

Under vacuum (as would be the case for idle and cruise), the inner spring seat rises up, increasing the control pressure and leaning the mixture.

http://forums.pelicanparts.com/uploa...1613922968.JPG

At atmospheric pressure (wide open throttle), the seat sinks down, lowering control pressure and richening the mixture. Total movement is about 0.5 mm.
http://forums.pelicanparts.com/uploa...1613922968.JPG

If anyone knows where I can find (Europe) the heating element (30 ohm) resistance, please lemme know.
It would be of a great help!

Check out this store named Missing Parts. https://www.ebay.nl/str/missingpartsde

Highly recommended. If you can't find what you need, send him a PM.

Contact information.........
 

Contact Info@missingparts.de and address it to Ruben. He has been very helpful in answering technical inquiries.

Tony

The difference between WUR’s........
 

Walt,

I will try my best to explain the difference between these WUR’s:

1. Vacuum assisted WUR from top........like WUR-033
2. Vacuum assisted WUR from bottom port.......like WUR-045/-069/—089.
3. Non-vacuum assisted WUR.....like WUR-072/-090.

First let’s us take a closer look at these WUR’s: So I picked several WUR’s and use them as demo for our discussion. They are WUR-033, WUR-045 (same as WUR-089 except for the heater value), and the lambda WUR-072 & -090. The first picture shows the completely assembled WUR’s and you will notice the difference between them just by looking closely.
http://forums.pelicanparts.com/uploa...1614031270.jpg

The next picture is the partially disassembled sections of the WUR’s. Oooops! I forgot the springs for WUR-045.
http://forums.pelicanparts.com/uploa...1614033123.jpg

Ok, I located the springs and installed them. The inner or outer springs for the vacuum assisted WUR’s are identical. So mixing the parts is not critical. And you could see the components for these WUR’s are some what similar but not the sections.
http://forums.pelicanparts.com/uploa...1614033346.jpg

Let’s go now to the schematics: Below is the WUR diagram for WUR -033. When you apply vacuum at the top port (#3), the “spring cap” where the inner spring sits would go up and increase the fuel pressure reading. However, if you apply vacuum to the vent port, the inner spring will not rise up. For this particular WUR-033, the vacuum chambers consist of the upper and middle sections.
http://forums.pelicanparts.com/uploa...1614034318.jpg

Below is a modified diagram for WUR-045/-089. I can not find from my books a good diagram so borrowed the WUR-033 and made some drawings. In comparison to WUR-033 (above), WUR-045/-089 have a totally different vacuum chamber configuration. The vacuum chamber is located solely in the middle section. And you could test it separately as a stand alone component. Plus this type of WUR has double diaphragm and allows the middle section to be an independent vacuum chamber from the top and bottom sections. Another added feature is that it is adjustable. WUR-033 and similar WUR are non-adjustable.

If you apply vacuum at the top port, it won’t increase the fuel pressure. Only at the side port where vacuum causes the fuel pressure to increase.
http://forums.pelicanparts.com/uploa...1614034555.jpg

If your car is a late SC US spec. it should not have a WUR-089 which is vacuum assisted. And your fuel distributor should be FD-077. I don’t remember if it was FD-031 or FD-077 you received from me but check it for me. It has been so many years since you got the FD from me. Do you have a specific question or test we need to do?

WUR-033 or WUR-045/-069-089 will work with FD-031 but not with FD-077 with lambda/OXS.

Tony

Many thanks!

Obrigado!

Back to this thread...
A new resistance installed.

http://forums.pelicanparts.com/uploa...1614817242.jpg

preparing for new measurements...

Starting with the cold control pressure:

Applied 16 hg vacuum on the wur, plunge the fuel pump relay, plug disconnected:

http://forums.pelicanparts.com/uploa...1614817511.jpg

1,5 bar CCP

After this, connected the wUR plug, vacuum still attached,

http://forums.pelicanparts.com/uploa...1614817702.jpg
http://forums.pelicanparts.com/uploa...1614817702.jpg
http://forums.pelicanparts.com/uploa...1614817702.jpg

The photos are not in order...

The correct order:
Right after connecting the wur plug, (15:36), WCP 1,6 bar
(15:38), 2,6 Bar
(15:40, 3,5 bar
(15:42), 3,7 bar

Right after, started the car, went for a ride till the engine reaches running temperature.
When arrived, WCP looking a bit higher.. 3,8 bar.

http://forums.pelicanparts.com/uploa...1614818381.jpg

... waited for another 20 min. , checked the residual pressure, (1,1 bar), started the car and... the same.
Struggles to start and when it starts it misfires (same as if the residual pressure is below specs, the car struggles a bit until system pressure is achieved).
Throttle down twice and the car is fine.

Note that after the last events and some wur tuning, the cold start became much more difficult.