CIS Experts - Are these WUR re-calibration steps correct?
 

Are these WUR re-calibration steps correct?

WUR model - Bosch 069 (with vacuum)

Current pressures:
System pressure 5 bar
Cold 3.3 bar @ 15C
Warm with vacuum 4.2 bar
Warm without vacuum 2.2 bar

According to Bentley they should be:
System pressure 5 bar (Something is right!)
Cold 1.7 bar @ 15C
Warm with vacuum 3.4 bar
Warm without vacuum 2.9 bar

My understanding of the issues:
The cold pressure is too high so I need to raise the post that holds the bi-metallic strip / arm
The warm control pressure with vacuum it too high so I need to lower the brass cap that holds the diaphragm in place
The warm control pressure without vacuum is too low so I need to raise the piston in the middle of the diaphragm

On to the plan - with the engine cold ....
(0) Connect fuel pressure tester by replacing the pipe from the fuel distributor to the WUR with the pressure tester ensuring the tap side is connected to the WUR
(1) Tap out the brass cap until nearly flush with case
(2) Tap out the post holding the bi-metallic arm so it is nearly flush with the case
(3) Loosen nut on the bi-metallic arm
(4) Using an allen key, raise the position of the piston in the middle of the diaphragm by turning clockwise .... maybe 2 revolutions (Any comments/advice)?
(5) Re-assemble and install without connecting the vacuum tubes or heater wiring
(6) Run the fuel pump only by shorting the relay (pin 30 to 87A)
(7) Open the valve on the pressure test gauge so that it reads 3.6 bar (Why 3.6 bar? ... Yesterday I did a job on this WUR and I set it to 2.9 bar, but found that it ended up at 2.2 bar when running without vacuum, so when running, it seems to make a difference of (2.9 - 2.2 = 0.7) bar. I'm not convinced I am right with this because the scale may not be linear and I have adjusted the piston in the diaphragm in step (4) - Any comments/advice?)
(8) Tap the brass cap in until I see a pressure increase on my gauge, then open the gauge valve a bit more to reset it back to 2.9 bar.
(9) Repeat (8) until the gauge valve is fully open
(10) Remove WUR, open and then tighten up the bi-metallic arm
(11) Re-assemble and install without connecting the vacuum tubes or heater wiring
(12) Open the valve on the pressure test gauge
(13) Tap in the post holding the bi-metallic arm until the gauge reads 1.7 bar (I did this yesterday too and I can't understand why the cold pressure is so far out of spec ....)
(14) Connect vacuum tubes and heater wiring
(15) Replace fuel relay
(16) Start engine and check cold control pressure is correct
(17) Watch the pressure raise from cold control to warm control pressure with vacuum and check if correct value
(18) Remove the bottom vacuum hose and check if warm control pressure without vacuum is correct

The variable here is step (4). If my guess is off the mark then I will have to repeat most of the steps above with the exception of the cold pressure steps. Some people talk about drilling a hole in the brass cap so that you can adjust the piston in the middle of the diaphragm without dismantling but I reckon this would mess up your vacuum side so I have no intention of doing this. Maybe you can use this trick on WUR's that don't have a vacuum control.

One thing that occurs to me, since I tried to set up the WUR yesterday using much of the above steps .....
(a) Is it coincidental that my cold control = system pressure - the value I set using the above method yesterday ( 3.3 = 5.0 - 1.7) or am I doing something wrong?
(b) Is it coincidental that my warm control without vacuum (nearly) = system pressure - the value I set using the above method yesterday ( 2.2 = 5.0 - 2.9) or am I doing something wrong?

And yes, I have read many of the CIS posts in the forum, but that doesn't mean that I understood them correctly. The above is the my understanding of the issues and my understanding of the solution (others be warned). I appreciate the confirmation / comments / advice on the above steps and maybe it will help others too.

You are making this way to complicated. Lets start all over, warm press MUST be set first, as the bi metallic spring has nothing to do with warm press. Warm press. is controlled by the tension on the little round spring. Take wur apart, tap large plug until it protrudes out of the housing by say, 3-4 MM, assemble wur, check warm press. It is going to be to low, so slowly tap large plug back into housing watch the gage. VERY SMALL INCREMENTS AND WAIT. until you are in the low 50lb range and stop. if you go to far, wur must come back apart to tap large plug back up and start over. on cold pres, on a cold enging, Or ambiant temp now that summer is here, works the same way, tap down little plug until your desired (best starting press) cold press is achieved. My car actually likes around 35lbs in the summer on a cold start, (I have a contrl press gage in the cockpit to monitor at all times) It is a trail and error proceedure, but you willl get the hang of it.

How does this affect the Warm without vacuum which should be 2.9 bar and is currently 2.2 bar?

I dont have the vac. controled reg, but i have taken a few apart. When car looses vac at throttle, the vacume pot lets the little round spriing come down, which will lower the pin, thus lowering the control press, (makes it rich) I didnt know there was an adjustment on the vac pot. I will go look at one in the shop in a bit, and let you know what I find.

that is correct. although i do not know if all vac WUR's have the adjustment.

there is an allen on the bottom of the diphragm that adjusts the compression on the inner spring, there are 2 springs on these WUR's. the spring is trying to push the diaphragm down, the vac is pulling up. once the vac drops, at higher RPM/WOT, the spring overcomes the power of the vac and the diaphragm starts to go down until it bottoms out, lowering the control pressure. thinking about this more, the inner spring will also have a effect on WCP, so trying to balance the WCP and when the WOT enrichment comes in will be a nightmare unless you know what vacuum will start to lower the CP.


the 3.6 bar is WITH vacuum. dont be that concerned about the pressure without vac. although it will be around .8-1 bar lower.

after thinking about your situation some more, your big problem is that you now have 3 adjustments to deal with instead of 2. unless you want to become and expert on WUR's the hard way, you may consider sending it off and having it rebuilt and calibrated. after all the time you spend, you may have a bad WUR and you are just taking years off your life.
my brother sent his 930 WUR off. the guy put in a heavy duty diaphragm, due to the boost, and made it adjustable and i believe he calibrated it. if you want, i can find out who did it or you can go over to the 930 forum and ask

personally i think it would be fun to mess with, as long as i had a working one to put in my car.

They are a pain to adjust with two settings, I can imagine having to do 3. But I would think your enrichment adj. on the dia. would be last to do??. They are fun to play with up to a certain point, and then you realise, there must be somthing better. I finally dumped the wur and went to a manual one that I can adjust on the fly, not for everyone, but it sure is fun dailing in you afr for any paticualar atmospheric conditions instantly.

My money's on "Brian Leask". He does nice work.

first pic is my reg. next few are of dailing in afr instanly. afr gage on top control press on the bottom. car come alive on the dyno at 49lbs of warm press (217 rwhp and counting) this cannot be achieved with the factory wur setting. They make a electronic one, but very expensive and lots of fiddling. this settup cost around 100 bucks and gives real flexibility on the afr. i can dail in for milage (28+ at 58 lbs) or performance.http://forums.pelicanparts.com/uploa...1275497453.jpg
http://forums.pelicanparts.com/uploa...1275497510.jpg
http://forums.pelicanparts.com/uploa...1275497561.jpg
http://forums.pelicanparts.com/uploa...1275497598.jpg
If you search for PaulPorche, he has written a short story on the wur, very helpful

Wow Don. That is a super setup. But that is a bit beyond me at the moment.

I am still going to have a go at getting mine right. With the pressures as they are, I am finding the warm up cycle poor and I am getting lots of popping on deceleration.

Even though I have a complicated repair procedure outlined above, the big questions for me are:

Will my repair procedure work since it is now clear I have 3 way adjustments to make?
and
Is my understanding correct?

I could send the WUR to London for repair (I live in Ireland) but apart from that option, I am on my own here.

take a look at your WUR, i think you can drill a hole in the bottom to get to the allen, if so, that will keep you from having to take it apart to adjust it because you will likely need to go back and forth adjustin the allen and knocking the plunger down. i would "preset" the allen CW to put more pressure on the inner spring as you said, i did not read all of you r procedure. the reason is, as you turn the allen CCW to release pressure on the spring, that will lower the vacuum required to keep the diaphragm up, but this will or may also lower the overall WCP so you will need to knock the plunger down to raise the WCP.
i would do this with vacuum on the WUR and the engine off.

my brother has the CIS gages, if i had them, i would check to see what vacuum the pressure starts to lower, this could be a BIG help if you new this. maybe someone can figure it out and let you know.

you need to get these 2 things set before trying to set the cold CP.


popping could be timing or you could just be lean.
when you cant get the relationship between warm and cold, its time to buy a new WUR.
check the heating element, should be around 30 ohms.

you may PM tony, he may have done this or may have some better ideas.



nice setup don.

Not sure about drilling a hole in the bottom to get at the allen bolt. Surely that would eliminate the vacuum altogether ......

Timing is good.

I am determined to get this thing back into spec.