Help me ID my WUR

peon77 · 12-18-2009, 10:25 AM

I am having some start up issues and I have measured the fuel pressures. but I am unable to find out the specs for my wur. Its PN is weird ep/lkw-v43 423024 for all the PN: skeptics I took a pic. I have searched and I can't find any mention of this PN. I could use some help.

Thanks
Pete

Forza · Forza's Garage

Here's a source for the specs of various Porsche CIS control pressure regulators (WURs):

WUR specs2

Here's another good source of info:

CIS Primer for the Porsche 911

As for identifying which WUR, the last three digits of the Bosch number is typically engraved on the top surface of the unit. For example, my '83 SC takes a Bosch 0-438-140-090 WUR, which has "090" engraved on it. I can see some number engraved on yours; you may need to disconnect some of the stuff at the top to determine which one it is.

ossiblue · 07:55 AM

+1 to what John posted.

On my wur, for a 76S, the last three digits which set the part aside from others is #033, and it's located approximately where the hose clamp in your photo is--a location we can't see from your picture. That being said, your wur doesn't have the other stampings on top either, as does mine, including the "0-438-140-090". You may have to remove some connections, as John suggested to find the actual wur ID.

Do you have a vacuum hose attatched to the bottom of the wur? If so, does it attatch to the side of the wur where the electrical connection is? If so, your wur is likely a "009".

peon77 · 12-19-2009, 08:49 AM

Ok guys removed it, doesn't help much with seeing the numbers. you can see a 3 but that doesn't tell much if you look closely to the elec. con. there is a portion of a no. that I don't think looks like it would be part of a 0 or a 3(as in 003/033). Near the fuel in/out there is a 10 etched. As for the vacuum I have only one line and its in the top not the bottom.

ossiblue · 09:11 AM

I'm certainly no expert, but that may not be a Porsche designated wur, which doesn't mean it won't work in your car. All I have seen/researched have numbers clearly on the top, and (for your model and year) a vacuum connection at the base.

I think someone who knows German or is familiar with Bosch codes--EP/LKW--may shed some light on this.

Walter_Middie · Walter_Middie's Garage

My 1975 looks just like yours. It has a vacuum hose on top, and an open tube on the side of the base plate for atmospheric pressure.

My Bosch book lists 1974 - 1977 specs together. There are cold control pressures listed for:

0 438 140 008
0 438 140 009
0 438 140 017
and
0 438 140 033

The book shows for a 1975 911S:
0 438 140 009

But like others have said, yours could have been changed sometime in its previous life.

peon77 · 12-19-2009, 09:21 AM

yea thats how I feel too. I have as much info suggesting its the right one as I do suggesting its the wrong one. None. I do have all the maintenance records, the car had always been serviced by Porsche prior to my ownership but all the records are in German.

peon77 · 12-19-2009, 09:32 AM

my control pressure is more in line with a 001 WUR. 2 bar @ 15c. If I should be in line with a 009 WUR my pressure is way too high. The last thing I want to do is throw parts ($) at the issue. Id like to be certain of what I have first

Gunter · Gunter's Garage

peon77.
Could be that it is a 0 438 140 033 but was rebuild by Bosch at some point and received a new plaque showing a rebuild-number?
That's what happens when the FD is rebuild.

The WUR can be taken apart, cleaned and re-assembled with a dab of grease on the top of the pin.

Is the heater element working?
You can check the resistance or apply 12V to see if it heats up within a few minutes.

peon77 · 12-19-2009, 10:03 AM

The resistance is 35 Ohms. I will take it apart since its all ready off of the car.
Walter just so I've got it right do you have a 009 Wur on your 75?
Thanks everyone

Gunter · Gunter's Garage

OK, you have resistance and the heater element should work but.............
Was there power to the WUR in situ?
Not sure about the '75S but on the SC's the WUR and AAR only get power with the engine running plus there is a tiny screen inside the nipple for the fuel line that can get dirty.
Do you have that small screen?
Careful with disassembly; there is a rubber seal between the upper and lower parts.

peon77 · 12-19-2009, 10:35 AM

I didnt check for the voltage. Ill do it when I get it all back together. The screen is in the input side. I will be carefull disassembly. Thanks Gunter.

ossiblue · 10:40 AM

Quote:

Originally Posted by peon77

The resistance is 35 Ohms. I will take it apart since its all ready off of the car.
Walter just so I've got it right do you have a 009 Wur on your 75?
Thanks everyone

My 75S had the 009. Even if yours was rebuilt by Bosch and retagged, it's still missing the vacuum connection at the base for wide open throttle that was present on 75s.

I guess in other threads you are having cold start problems, thus Gunther's information? This brings up a question that I had that relates to your problem.

If you have a different WUR for a particualr engine model/year, using the CIS tables, should the pressures be set to the WUR specs as if it's on the correct engine or to the specs of the engine/model year regardless of the WUR used?

If you have a different WUR, the answer to the posed question could be important. I suspect the answer will have something to do with the other CIS components, esp. the fuel distributor.

Forza · Forza's Garage

Quote:

Originally Posted by Gunter

peon77.
Could be that it is a 0 438 140 033 but was rebuild by Bosch at some point and received a new plaque showing a rebuild-number?

I don't think it's a '033; those models had the vacuum connection at the bottom, which the pic above lacks:

Regardless, do you know which of the WURs for '75s was original for your S? Was it the '017? If so, perhaps the WUR currently installed was rebuilt to those specifications, but using he vacuum connection on the top of the unit. I'm pretty sure all the possible replacements for that year (008, 009, etc.) had vacuum connections on the bottom, FWIW.

Walter_Middie · Walter_Middie's Garage

Quote:

Walter just so I've got it right do you have a 009 Wur on your 75?

Yes, mine is stamped 009 on the top. I was curious so I removed mine and took some pictures. I was wrong about the open tube on the base plate. Mine does not have an open tube to the atmosphere. I thought it did, but it does not. Only the vacuum line on top.

peon77 · 12-19-2009, 11:15 AM

Quote:

Originally Posted by ossiblue

If you have a different WUR for a particular engine model/year, using the CIS tables, should the pressures be set to the WUR specs as if it's on the correct engine or to the specs of the engine/model year regardless of the WUR used?

If you have a different WUR, the answer to the posed question could be important. I suspect the answer will have something to do with the other CIS components, esp. the fuel distributor.

Yes thats where I am heading. Since 009 is indeed used on a 75 I will adjust mine to the specs for that wur. After I check it for blockages of course. I will go look at what FD I have.

Gunter · Gunter's Garage

Numbers on the FD?

'75S - Bosch FD 0 438 100 006 new, 0 986 438 006 replaced.

peon77 · 12-19-2009, 11:34 AM

Numbers on the FD are 0 438 100 004.

peon77 · 12-19-2009, 12:32 PM

I have found a pic out of my 911 workshop manual volume III pg. 0.1-3/10. It is an identical WUR right down to how the numbers are cast into the top with the elec plug through them. It has a plate riveted on the front with very similar numbers to mine. So I am reasonably convinced it is original. Now back to the disassembly.

Walter_Middie · Walter_Middie's Garage

I agree with Gunter - my Bosch book shows FD 0 438 100 006 for the 1975 911S. However, this site:

http://www.specialtauto.com/fuel-distributors.html

shows your number for 73 to early 75 911.