Warm control pressure

[paulj]

Hi from England. Aug 1980 SC. I'm having a problem with my warmup regulator. I've converted to adjustable but can't get the warm control pressure high enough. I've got a new pump and main fuel pressure is fine measured at the supply to the regulator. I've tryed with the bimetalic strip removed so assume the springs are weak. Anyone fixed this? I thought of stretching the springs but thats not measurable. I also thought of machining blocks to take set screws to depress the valve housing deeper into the main casing so i could set the warm control pressure that way or is it time to junk the old regulator, just worried about how accurate a new one would be anyways. Would like to have control over the settings but cant afford the solid state alternative. Any thoughts would be welcome.

[ossiblue]

Paulj,

Welcome to the forum (and post pictures of your car as soon as possible--we love 'em here!)

Something in your post caught my eye--"I've tryed with the bimetalic strip removed so assume the springs are weak.". If you removed the bimetallic strip, how were you able to secure the pin into the hole of the diaphragm housing? Assuming you were able to keep the pin lined up with the hole, are you sure it was there when you reassembled the wur?

You're on the right track in thinking of pressing the diaphragm housing down into the body to increase warm pressure but you have to be absolutely certain the bimetallic spring and the coil springs are fully warm and extended.

Here's what I did and is something you might try:

Disassemble the wur, remove the bimetallic arm, pin and springs. Using a large socket, tap the plug holding the diaphragm upward in the housing so a bit more is exposed from the top/outside. Next, using a large C-clamp, gently press the plug that the lever is bolted to upward so the top of the plug is nearly flush with the top of the wur housing on the outside (You can do this using your adjusting mechanism.) Now, reassemble the wur, making certain the pin is able to reach the hole in the diaphragm plug and also remains in the carrier which is sitting on the spring (I call it the "clown hat". Put some grease in the clown hat to hold the pin so it doesn't slide out.)

Now comes the important part. Put the wur back on the car and hook up your fuel pressure gauge set-up. If you've done everything right, when you turn on the fuel pump, the pressure should be too low to start the car. Use the valve on the pressure gauge to cut down the flow to the wur until you reach cold starting pressure. Hook up all connections to the wur and start the car.

Let the car warm to running by gradually increasing the pressure with continued closure of the valve on the gauge--up to about 3.4 bar or whatever is warm controlled pressure for your car. Let the car run until you are certain the engine, wur, and bimetallic spring are thoroughly warmed to full operating temperature.

When the car is warm, use a long socket extension or some other similar object and carefully tap the diaphragm housing back down into the wur housing (alternate taps on each side is best) and watch the pressure gauge. Tap the housing down until you see a slight rise in pressure, then, open the valve on the gauge a bit to bring the pressure down to warm specs again. Continue this process until the pressure is at warm spec with the valve completely open. WORK SLOWLY! This will set your warm controlled pressure. Wait until the next day, and set the cold control pressure.

If you do the above procedure and the pressure fails to rise, then you may have allowed the pin to slip out of the hole in the diaphragm or possibly a leak in the diaphragm itself

Sorry this is so long, but I've done this several times on different cars and it worked perfectly

[enjefriy]

Hi Paul J,
I've had recent dealings with my WUR as well, so am no expert. But the set up of the WUR is somthing i've just done.
Ossi-Blue has described the procedure so well, that i would reconsider redoing mine now.

But i wanna ask why you need to work on this WUR of yours. What was the original issue.
I actually carried out a mod on mine to make it into an adjustable WUR, but would like to caution you to get the correct specs for the WUR fitted to your car. (Thks JIM).
(not all WUR work to the same pressures). My experience was due failure to re-start my car. I misdiagnosed the cause, so i was attacking it from the WUR). Lucky for me, Gunter, Tony, and many more sorted me out)

Anyway, if the WUR is something you just need to set up, then you need to identify the P/n of your particular WUR, then you'll get the specified Cold & Warm control pressures, for that particular WUR.

Food for thought:
-Have you problems with Cold or warm Starts?
-Does the Bimetallic strip still function?
-Does your WUR have a Vacuum port on the side, (ie. apart for the port on top)?

I wasn't very detail on my description when i had a problem. It made it very difficult for the gentlemen on the forum to help me out.

Maybe you could post a pict of the WUR.
I'll try post some link/Picts too, for reference.

[enjefriy]

[T77911S]

very good ossi. the key thing i was looking for is for him to set the warm pressure first, then the cold. this could be an easy mistake for someone to make.

i would do it with the key on and FP off to get the WUR warm, but either way.

make sure you have 12v to the WUR. if this does not help-bad WUR.

[Paulporsche]

I used the method described by Ossiblue (told to me by stevemfr, and thanks again, Tony) about a year ago with great results.

If the above doesn't work, you may have a bad bimetallic spring, as you mentioned. If this is the case, you can try substituting one from another used WUR, but this spring seems to be the thing that most often fails on these units. I had my WUR rebuilt by someone near San Francisco, but I still had to reset it as Ossi describes, once I got it on the car.

Someone asked whether you have a vac controlled WUR. US 80s engines didn't but you may have in England. Either can work. I have a vac one on my 80 engine. The important thing is the control pressures.

Just to state the obvious: make sure all ignitioin components are working to spec, and (if you hav a vac unit) that there are no vacuum system leaks.

[paulj]

Ossie , I'll be doing what you said. Thanks. It certainly makes sense that you have to set warm first. To try the regulator with the bimetallic strip out I turned a tube id to be an easy sliding fit on the pin carrier diameter and then supported it all with alot of plasticine ( I've got alot of kids ) on the three closed sides of the main casting. I think it was a valid test as I did get a warm contol pressure of 2.5 bar which would be much less if the pin had fallen out. This was also the same pressure I 'd got after modifying the warm up regulator as per Engifriy's diagram.
More info as per requests;
Inital prob was poor cold idle and surging.
The heater element has a resistance of 36 ohms and heats up.
The bimmetalic strip bends when heated.
WUR is correct for the car and prob 30 years old.
It has the side as well as the top vacuum connections .
I checked ignition then vacuum. Checked the auxillary air valve was closing as it should and then got bored and got the fuel pressure gauge out that told me I had no cold control pressure. I wondered wether the guage was faulty but checked main fuel pressure and this was spot on. I then stopped and modded the WUR when I should have carried on and got a warm control pressure. Put it all back together , jumped the pump set the cold pressure to 1.75 bar , fired her up and perfect. Then waited and as she got hotter the pressure only rose to 2.5 bar.
Will get some pics at the weekend. Its a good unrestored white and black targa, pacha, 16" fuchs, green tints, no spoilers but it does have a working factory cruise control.

[T77911S]

no cold control pressure? as in zero?

2 vacuum ports? post the part number off the WUR.
your car does not use vacuum on the WUR. they stopped that in 79?. the vacuum on the port would raise the pressure .8-1 bar.

[boyt911sc]

Originally Posted by paulj

Ossie , I'll be doing what you said. Thanks. It certainly makes sense that you have to set warm first. To try the regulator with the bimetallic strip out I turned a tube id to be an easy sliding fit on the pin carrier diameter and then supported it all with alot of plasticine ( I've got alot of kids ) on the three closed sides of the main casting. I think it was a valid test as I did get a warm contol pressure of 2.5 bar which would be much less if the pin had fallen out. This was also the same pressure I 'd got after modifying the warm up regulator as per Engifriy's diagram.
More info as per requests;
Inital prob was poor cold idle and surging.
The heater element has a resistance of 36 ohms and heats up.
The bimmetalic strip bends when heated.
WUR is correct for the car and prob 30 years old.
It has the side as well as the top vacuum connections .
I checked ignition then vacuum. Checked the auxillary air valve was closing as it should and then got bored and got the fuel pressure gauge out that told me I had no cold control pressure. I wondered wether the guage was faulty but checked main fuel pressure and this was spot on. I then stopped and modded the WUR when I should have carried on and got a warm control pressure. Put it all back together , jumped the pump set the cold pressure to 1.75 bar , fired her up and perfect. Then waited and as she got hotter the pressure only rose to 2.5 bar.
Will get some pics at the weekend. Its a good unrestored white and black targa, pacha, 16" fuchs, green tints, no spoilers but it does have a working factory cruise control.

paulj,

You could check your WUR for warm control pressure without the need of running your engine. Why waste fuel when you cold do the test with a non-running engine? Search for 'ricks911s' about Chasing CIS Demons (page 3). You'll find a very helpful video he has made and could benefit many CIS troubleshooters. Guys have given you many good advises for you to solve this problem. BTW, what's the number on your WUR (0-438-140-xxx)?

Tony

[paulj]

WUR part no is 0 438 140 089, please remember this is a UK car, we have vacuum at this age, WUR is correct. Spec says warm control pressure should be 3.4 to 3.8 bar. Should this be set with vacuum on or off? Thanks for all of your input. Going to look at Ricks pages now.

[enjefriy]

Hi Paul,
We have the same type of WUR P/N.
The Warm control pressure of near 3.8 bar is with the vacuum supplied. (vacuum connection on the side, Not the top one).
The diagram i put on is off a US version, but i posted it just to show the adjustability mod.

Anyway, with the 089 WUR (ROW/Euro), the Springs sit on a piston, which will raise when vacuum is supplied. So therefore, when more vacuum applied, increase in control pressure is obtained.

I have had problems with obtaining the specified Warm pressure as well, and found that the Piston seal was not sealed, and hence prevented the raising of this piston with vacuum applied.

Regardless however, the procedure described by Ossi still stands. The absence of vacuum would only account for about 0.4-0.6bar of pressure anyway (depending on how much vacuum is applied), so you should atleast be able to shoot for a Warm control pressure of about 3.4 bar without the vacuum.

Like Tony says, you could still do the test without the engine running, however on mine, i found that the power supply to the Bimetallic Strip was only available with the engine running. (i suppose u could just supply it with 12Vdc from another source)
For the vacuum, i supplied it with a mityvac, as the Bentley states it to be 13-15inHg.
So warm control pressure would be quoted w/out vacuum applied, as well as with vacuum applied for comparison.

[T77911S]

you also have to have the WUR connected to the correct port on the throttle body. the WUR should have vacuu, on it all the until you go wide open throttle WOT.

if you have a hand vac pump, connect it to each port and you chould see one, the side one, raise the WCP. or, if you remove the vac, you should see the CP go down.

[paulj]

I think I've cracked it with your info. With the top vac off, vac applied to the side port is only raising the control pressure 0.2 bar not 0.8 to 1.0. I've clamped the side vac pipe with vac applied and the pressure remains constant. I think the seal is ok but the piston isn't moving through its full travel and that would account for the loss of approx 1.0 bar control pressure I have cold and warm. I'll pull it off at the weekend and let you know.

[paulj]

I've got good cold and warm pressures now . The engine is running sweet again. The vac is now giving 0.5 bar up from 0.2. I suppose this is because the piston resting position is now lower after tapping the valve housing down giving it more upward deflection. Still not 0.8 bar though but I think I'll leave it at that. I'll be checking the control pressures at service time from now on. Thanks for all your help.

Paul

[boyt911sc]

Originally Posted by paulj

I've got good cold and warm pressures now . The engine is running sweet again. The vac is now giving 0.5 bar up from 0.2. I suppose this is because the piston resting position is now lower after tapping the valve housing down giving it more upward deflection. Still not 0.8 bar though but I think I'll leave it at that. I'll be checking the control pressures at service time from now on. Thanks for all your help.

Paul

Paul,

Congratulation for fixing the problem. Could you share the information to others? Please state the values of your fuel pressures you got. "I've got good cold and warm pressures now" would be more descriptive if you include the values in your post. This would be helpful to other readers too. Thanks.

Tony

[paulj]

Sorry, got 1.75 bar cold and 3.7 bar hot.

[boyt911sc]

Originally Posted by paulj

Sorry, got 1.75 bar cold and 3.7 bar hot.

Paul,

These numbers are very good!!!! For your reference, I would suggest that you record the WUR's characteristics. For example record the control pressure from start, 30 sec.,90 sec. 120 sec. and so on until you get to the max. control pressure(warmed by the heater only). If you had the chance to view Ricks911S video, you'll find how he did the test with engine off. Keep us posted. Thanks.

Tony