Building adjustable WUR need starting point

Vereeken · 02-07-2012, 12:12 PM

In order to get to terms with my rough cold starts on my Euro SC i am building a WUR 089 out of good parts.

I already have the 35 ohm bi-metal in place which is different to US cars.

My question to you CIS/WUR experts.

The pin is drilled, so how far do I knock it in to start with? I was thinking that i would only knock it as far in as I need to in order for the springloaded pin inside the WUR to be touching its little hole in the diafragm.

To me that makes sense as i can not believe that the pin will remain seated in the little hole should it ever be allowed to come out.

Is my thinking right?

boyt911sc · boyt911sc's Garage

You need to understand why you are making it adjustable. Is the problem at cold control pressure or warm cntrol pressure? Then to do the adjustment, you need to measure the control pressure with the fuel gauge connected. Plus the control fuel pressure is related to the system fuel pressure.

I've been following your troubleshooting saga and it would be very difficult to correct your problem/s because you don't know what's causing it in the first place. The pin you are showing is the part that pushes up the metallic diaphragm inside in the WUR. That is not the pin used for adjusting the cold control pressure.

Tony

ossiblue · 05:36 PM

In order to avoid confusion, I will use the term "plug" to mean the pin you drilled out that holds the bi-metallic arm, and "pin" to mean the pin which pushes on the diaphragm.

Do just the opposite of what you propose. That is, do not knock the plug down but rather, press it upward in the housing so it does not contact the spring holding the pin at all, or just barely touches it.

The bi-metallic arm only contacts the spring to control the pin when the wur is cold and should be free and clear of the spring during warm running. When adjusting a wur for the first time, the warm control pressure should be set first with the arm clear of the spring.

Assemble your wur with the arm away from the spring (or just grazing it), and the pin in the hole of the diaphragm. Hook up your pressure gauge set and activate the fuel pump. Energize your connection to the warm up coil on the wur and allow it to fully heat/bend the arm away from the spring. Read your warm control pressure. If it is too (high) (correction--too low, thanks Tony)you can tap downward on the round cylinder that holds the fuel inlet/outlet ports and that will begin to lower(correction: raise) the wcp (do this slowly so you do not drive the cylinder too low into the wur housing.) If the wcp is too low(correction: high), you will need to disassemble the wur and press the cylinder upward in the housing, reassemble, and repeat the above sequence.

Now, once the warm control pressure is set, you need to let the wur completely cool to ambient temperature. When the wur/engine is completely cold, proceed with setting the cold control pressure by either knocking the plug downward to lower the pressure, or using your adjusting nut to raise the plug if the cold pressure was too low.

edit: Tony posted while I was typing and it appears you have other issues that may not be related to the wur. My advice, above, is to address only your question of how to first assemble your wur and set it properly. If that is not your issue, at least you will have the wur out of the equation as a cause.

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by ossiblue

In order to avoid confusion, I will use the term "plug" to mean the pin you drilled out that holds the bi-metallic arm, and "pin" to mean the pin which pushes on the diaphragm.

Do just the opposite of what you propose. That is, do not knock the plug down but rather, press it upward in the housing so it does not contact the spring holding the pin at all, or just barely touches it.

The bi-metallic arm only contacts the spring to control the pin when the wur is cold and should be free and clear of the spring during warm running. When adjusting a wur for the first time, the warm control pressure should be set first with the arm clear of the spring.

Assemble your wur with the arm away from the spring (or just grazing it), and the pin in the hole of the diaphragm. Hook up your pressure gauge set and activate the fuel pump. Energize your connection to the warm up coil on the wur and allow it to fully heat/bend the arm away from the spring. Read your warm control pressure. If it is too high, you can tap downward on the round cylinder that holds the fuel inlet/outlet ports and that will begin to lower the wcp (do this slowly so you do not drive the cylinder too low into the wur housing.) If the wcp is too low, you will need to disassemble the wur and press the cylinder upward in the housing, reassemble, and repeat the above sequence.

Now, once the warm control pressure is set, you need to let the wur completely cool to ambient temperature. When the wur/engine is completely cold, proceed with setting the cold control pressure by either knocking the plug downward to lower the pressure, or using your adjusting nut to raise the plug if the cold pressure was too low.

edit: Tony posted while I was typing and it appears you have other issues that may not be related to the wur. My advice, above, is to address only your question of how to first assemble your wur and set it properly. If that is not your issue, at least you will have the wur out of the equation as a cause.

Larry,

It should be the other way around (????). Plug pressed down, cold control pressure goes down. Cylindrical block pushed down, warm control fuel pressure goes up and vice versa.

Tony

ossiblue · 02-07-2012, 05:31 PM

Quote:

Originally Posted by boyt911sc

Larry,

It should be the other way around (????). Plug pressed down, cold control pressure goes down. Cylindrical block pushed down, warm control fuel pressure goes up and vice versa.

Tony

Tony,

You're absolutely right--another senior moment! I'm going to correct it and give credit where credit is due. (I must be a bit "off" today. Winter came today and it's in the 60's and slightly raining! Oh well, tomorrow is supposed to be 73 and sunny and all will be good again in SoCal.)

proffighter · proffighter's Garage

I don't have a WUR, but this is maybe nice to see:

Vereeken · 02-07-2012, 11:19 PM

Ossiblue,

Thanks. That is what I am looking for. So my thinking was right but my English was off, my bad.

Indeed. I have made the PLUG adjustable and was asking where to more or less put the PLUG the first time around in relation to the PIN that pushes on the diafragm as I did not have any reference.

Tony I do not know where my problem is until I take measurements but I needed a starting point as this is a WUR built from spare parts. And to complicate things this is a WUR with double spring for vacuum activation of the second membrame which is common in EURO SCs.

I think I have a cold pressure problem on the existing WUR since the car does not want to do the warm-up routine straight away and I have already ruled out AAR and Thermo time Valve. Also the TTS is working and within spec and the CSV is getting 12 V when starter engaged. I do not now if the CSV is leaking but it is spraying when hooked up out of the car.

My warm idle is perfect with no stumbling and an AFR of about 13.6. Also warm starts are no issue. I already refurbished the PPR valve. Need to check the accumulator.

When the CIS test kit is In i will post pressures.

So in summary the bimetallic arm will most likely only deflect a little when really cold.

If I start with the arm resting but not pushing on the springs at room temperature I suspect I will have a cold control pressure that will be too high too start with.

I really hope this is going to solve it cause after this I am only left with Accumulator, a leaking CSV or a FD and teh first two do not fit the symptoms.

Michel

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by Vereeken

Ossiblue,

Thanks. That is what I am looking for. So my thinking was right but my English was off, my bad.

Indeed. I have made the PLUG adjustable and was asking where to more or less put the PLUG the first time around in relation to the PIN that pushes on the diafragm as I did not have any reference.

Tony I do not know where my problem is until I take measurements but I needed a starting point as this is a WUR built from spare parts. And to complicate things this is a WUR with double spring for vacuum activation of the second membrame which is common in EURO SCs.

I think I have a cold pressure problem on the existing WUR since the car does not want to do the warm-up routine straight away and I have already ruled out AAR and Thermo time Valve. Also the TTS is working and within spec and the CSV is getting 12 V when starter engaged. I do not now if the CSV is leaking but it is spraying when hooked up out of the car.

My warm idle is perfect with no stumbling and an AFR of about 13.6. Also warm starts are no issue. I already refurbished the PPR valve. Need to check the accumulator.

When the CIS test kit is In i will post pressures.

So in summary the bimetallic arm will most likely only deflect a little when really cold.

If I start with the arm resting but not pushing on the springs at room temperature I suspect I will have a cold control pressure that will be too high too start with.

I really hope this is going to solve it cause after this I am only left with Accumulator, a leaking CSV or a FD and teh first two do not fit the symptoms.

Michel

Michel,

A suggestion was given in your other post about checking the fuel pressures. You mentioned that COLD start was the problem and starts OK when warm. So what is your cold control fuel pressure? You have not tested the WUR that is installed in your engine or if you did, you have not shared with us the data (fuel pressure readings).

I would like to suggest that you check the old WUR first before blaming it for the problem/s. From what you have described, you might have too much cold control fuel pressure. Checking the pressure would be my next move. Keep us posted.

Tony

Vereeken · 02-08-2012, 06:55 AM

Tony,

I have indeed never shared the pressure readings on the existing 089 in my car.
It was New Old Stock straight out of the box. At the time I installed it I only read my system pressure which was good. I understand now that in fact it does not tell you a lot. I am only used to Carb engines and EFI.

I am waiting for the CIS fuel tester to come in that I ordered from Pelican, but I live in Belgium so it will take a couple of days.

I have the luxury of haveing two 089s now. One stock and One with adjustable plug. I never gave much about modifying it but now that I see what a crude thing it is I just might use the adjustable one and fiddle with it.

You could be right that I have too much (Too LOW CCP). I believe in that case the engine would flood and would be difficult to start which is the same symptom as too high CCP except for the flooding.

In the end I can make a career out of this.

As soon as all is in I will test and draw a graph in 30 sec intervals.

If you could shed some light on that test that would be great.

Michel

T77911S · 02-08-2012, 07:11 AM

Quote:

Originally Posted by Vereeken

Ossiblue,

I do not now if the CSV is leaking but it is spraying when hooked up out of the car.

Michel

just to be clear. its sprays ONLY when power(12v) is applied to it? or, does it spray with fuel pressure only and no power?

Vereeken · 02-08-2012, 07:16 AM

Only when 12v is applied to it it sprays.
But I did the test on a 3bar system out of the car and not in the car itself.
So I would like to make sure it does not leak when connected to the 911 fuel system as that seems to be running higher.

ossiblue · 08:07 AM

Quote:

Originally Posted by Vereeken

Ossiblue,

Thanks. That is what I am looking for. So my thinking was right but my English was off, my bad.

Indeed. I have made the PLUG adjustable and was asking where to more or less put the PLUG the first time around in relation to the PIN that pushes on the diafragm as I did not have any reference.

Tony I do not know where my problem is until I take measurements but I needed a starting point as this is a WUR built from spare parts. And to complicate things this is a WUR with double spring for vacuum activation of the second membrame which is common in EURO SCs.

I think I have a cold pressure problem on the existing WUR since the car does not want to do the warm-up routine straight away and I have already ruled out AAR and Thermo time Valve. Also the TTS is working and within spec and the CSV is getting 12 V when starter engaged. I do not now if the CSV is leaking but it is spraying when hooked up out of the car.

My warm idle is perfect with no stumbling and an AFR of about 13.6. Also warm starts are no issue. I already refurbished the PPR valve. Need to check the accumulator.

When the CIS test kit is In i will post pressures.

So in summary the bimetallic arm will most likely only deflect a little when really cold.

If I start with the arm resting but not pushing on the springs at room temperature I suspect I will have a cold control pressure that will be too high too start with.

I really hope this is going to solve it cause after this I am only left with Accumulator, a leaking CSV or a FD and teh first two do not fit the symptoms.

Michel

I would advise you to set the arm slightly above the spring if you are assembling the wur at room temperature. Remember, you are setting the warm pressure first and that requires the arm to be completely free of pressure on the spring/pin. When the wur is mounted on the engine and the outside temperature is colder, the arm could continue to bend downward--depending on the difference between "room" temperature and the outside temperature. When you energize the heating coil, you need to be certain the arm has moved completely free of the spring so the warm pressure is accurate. I would error on the side having the arm too far off the spring as that would guarantee the arm (when fully heated) has no influence on the spring. Since you are setting an adjustable wur, you could easily give the adjusting nut a few turns to pull up the plug to ensure the arm is off the spring.

Vereeken · 03-16-2012, 02:58 AM

Ok, I finally got my pressure tester kit no thanks to our customs boys in Belgium (2 days from LA to Brussels about 10.000+km, 5 weeks from Brussels to my house about 40km)....

These are my results -I know they do not look good....but give me your opinion advice on what to do next. This is a 089 WUR on a EURO SC.

Temp outside was 10° celcius (50 Fahrenheit).

System pressure 4.7 bar (within spec of 4.5-5.2 bar).
WUR cold pressure 12 V disconnected : 0,4bar (Target should be 1bar).

After 60seconds with 12V applied 0,8 bar
After 120seconds 1 bar
Final value reached 1.8 bar maximum.

Knowing that I need to get to 2.9/3.2 this is a terrible result for a NOS WUR.

What do you suggest? Work on the new WUR? replace it with my old WUR that has been made adjustable?

What is the direction I have to drive the pin in order to get my desired pressure? Down or upwards?

Big thanks already.

Michel

T77911S · 03-16-2012, 03:30 AM

this is a WUR you built out of parts, correct?

the part with the fuel lines attached has to go down. set it first and set it with it hot.
moving it down increases pressure on the spring that closes the diaphragm, thus raising the pressure.

the next day, set the cold pressure.

check post #6 above.

Vereeken · 03-16-2012, 04:08 AM

TT thanks, Warm first then cold.

I have 2. One original one built out of parts.

By pointing out the cirlcle with the fuel lines attached to me, I indeed notice that it sticks out more then I remember on other WURS...strange.

So asssuming I want to work on the NOS rather then the one I built myself out of parts, can I tap the big circle easily inwards (after removing the fuel lines ofcourse.
It looks like it is threaded but perhaps I am mistaken. Or do I need to make it truly adjustable?

Michel

boyt911sc · boyt911sc's Garage

Quote:

Originally Posted by Vereeken

TT thanks, Warm first then cold.

I have 2. One original one built out of parts.

By pointing out the cirlcle with the fuel lines attached to me, I indeed notice that it sticks out more then I remember on other WURS...strange.

So asssuming I want to work on the NOS rather then the one I built myself out of parts, can I tap the big circle easily inwards (after removing the fuel lines ofcourse.
It looks like it is threaded but perhaps I am mistaken. Or do I need to make it truly adjustable?

Michel

Michel,

Roland had given you a very good reference (picture). The circular disk is not threaded but it is mounted very tight (forced fitted). You would need a great deal of pressure (force) to moved it (up/down). It would be ideal to make the adjustment with the fuel pressure gauge reading or recheck pressure after each micro adjustment. HTH.

Tony

T77911S · 03-16-2012, 07:16 AM

if you have a new unmolested WUR, i would not touch it. take the one you built and "play" with it.

Vereeken · 03-16-2012, 07:29 AM

Ok, I am now at 3.1 bar after 4 minutes of heating the element with 12v at 17 degrees Celcius.

How does this sound?

Am I ready to adjust cold control pressure tomorrow?

Michel

1982911SCTarga · 03-16-2012, 08:35 AM

Quote:

Roland had given you a very good reference (picture). The circular disk is not threaded but it is mounted very tight (forced fitted). You would need a great deal of pressure (force) to moved it (up/down). It would be ideal to make the adjustment with the fuel pressure gauge reading or recheck pressure after each micro adjustment. HTH.

You can carefully tap the large circular disk up or down. I do this when calibrating the final warm control pressure to spec. This adjustment is made with the bimetallic strip's pin flush with the WUR body, so that the strip is not acting on the spring and diaphragm pin inside.

Once you've got the warm control pressure set, then knock the pin and use the adjustability feature you've now built in to the WUR to set the cold control pressure.

There's a thread here about the process.

Hope this sheds light rather than confuses people.

Brian

Vereeken · 03-17-2012, 10:09 AM

No it is totally clear.

The big round disc sets the warm ccp the small pin the ccp.

I have adjusted my warm and I noticed an immediate improvement in cold start the morning after.
I then slightly decreased my ccp.

So it looks like i am on the right track. I can see how warm cp affects ccp if I look at the picture.

But boy is this fiddly.

Michel