82 SC high control presure.

[Bill wjw]

Hi again
1982 SC Stock USA
090 WUR

System Pressure 4.3 bars This has always tested low in the 4 years I have had the car. Even with a new fuel filter. No kinks in the line. I have not taken out the screen in the fuel tank to check for blockage. It looks like adding one shim to the fuel pressure regulator should solve that problem.

Cold Pressure 3.4 bars

5, 10 and 15 minutes all 3.9

Engine temp cold between 18 1nd 20 degrees C

This is off the chart high. Cold starting has been the current issue. It fires right up and then often dies or idles at low and rough rpm. When the engine warms up it does run but has occasional misses on acceleration.

Last week on my way home from work I started it but did not wait for full warm up before leaving the parking lot. It pop and stumbled down the road. It stalled at the second stop sigh and would not restart. I could get it to fire, probably from the cold start valve, but not idle. I had it towed home and got it to run after sitting for an hour. Poor cold running and smoother out upon warming.

I have the WUR out and am tempted to take it apart with a talented technician I work with. What are my options here?

[Tidybuoy]

Besides adding one shim to the FD pressure regulator, check the condition of the small o-ring at the end as this is what is stopping the flow of fuel until the spring compresses. Also, check how long fuel pressure holds up after the car is turned off as a weak or worn o-ring will cause the pressure to decrease pretty fast.

Others on the forum have much more expertise than me so maybe wait for a few more suggestions before doing anything.

[boyt911sc]

Originally Posted by Bill wjw

Hi again
1982 SC Stock USA
090 WUR

System Pressure 4.3 bars This has always tested low in the 4 years I have had the car. Even with a new fuel filter. No kinks in the line. I have not taken out the screen in the fuel tank to check for blockage. It looks like adding one shim to the fuel pressure regulator should solve that problem.

Cold Pressure 3.4 bars

5, 10 and 15 minutes all 3.9

Engine temp cold between 18 1nd 20 degrees C

This is off the chart high. Cold starting has been the current issue. It fires right up and then often dies or idles at low and rough rpm. When the engine warms up it does run but has occasional misses on acceleration.

Last week on my way home from work I started it but did not wait for full warm up before leaving the parking lot. It pop and stumbled down the road. It stalled at the second stop sigh and would not restart. I could get it to fire, probably from the cold start valve, but not idle. I had it towed home and got it to run after sitting for an hour. Poor cold running and smoother out upon warming.

I have the WUR out and am tempted to take it apart with a talented technician I work with. What are my options here?

Bill,

Is this a typo? A system pressure of 4.3 bar (62.4 psi) is too high!!!!! Maybe it is 3.4 bar (49.3 psi.)? A hairline thicker shim could be added. The cold control fuel pressure is too HIGH too. I would be surprised if you could make it start and idle smoothly. You have to address the following:

a). Fuel distributor system pressure setting.
b). WUR control fuel pressure setting.
c). Check your delivery and return lines for any sign of flow restriction.

PM me if you need assistance checking and testing your WUR and FD for FREE. Just pay the shipping cost round trip and I will provide you all the information about these parts.

Tony

[Bill wjw]

hi Tony,
according to the Bentley- system pressure Engine off, pump running 4.5 -5.2 bars. Is this information incorrect for my car?


I have been using the search and will go home tonight, drain the fuel tank and check out the condition of the return line.

Also take out the fuel pressure relief valve and inspect. Where can one get suitable shims. Do you know the size off hand?

Hopefully I can get this running here as I am anxious to take the top off and go for a drive. If it continues to befuddle me I will certainly take you up on your kind offer.

[boyt911sc]

Originally Posted by Bill wjw

hi Tony,
according to the Bentley- system pressure Engine off, pump running 4.5 -5.2 bars. Is this information incorrect for my car?


I have been using the search and will go home tonight, drain the fuel tank and check out the condition of the return line.

Also take out the fuel pressure relief valve and inspect. Where can one get suitable shims. Do you know the size off hand?

Hopefully I can get this running here as I am anxious to take the top off and go for a drive. If it continues to befuddle me I will certainly take you up on your kind offer.

Bill,

My mistake. I was referring to the control fuel pressure and used the wrong conversion table. Your system fuel pressure should be between 65 - 75 psi (4.5 - 5.2 bar) and you have the correct values. The shims are not easy to find at your local hardware stores. Measure your shim/s thickness and fabricate a suitable shim if you could not locate one. Did you try to look at our host's parts catalog?

Your system pressure of 4.3 bar (62.4 psi.) is low and could be leaking (?). If the primary valve is not leaking set it between 70 - 72 psi. I prefer the higher value of 72 psi. And your WCP should be around 50 - 55 psi. I apologize for the confusion earlier.

Tony

[L8apex32]

Bill,
First things first. The system pressure is too low. You know how to measure it and you know what controls it. Add a shim as necessary and work through that issue first. I had a copper washer around that I added to get my pressure towards the high end of the range - I think I added a thick one and removed a thin one to end up at the pressure I needed.

Next, control pressure is too high. The WUR should let the fuel flow back to the tank. Is it? Perhaps you could have the fuel leave the WUR and go directly to a container to isolate it from the rest of the fuel system. With the CIS test kit it sounds like you have, you can close the valve, then open it just long enough to measure the flow through the WUR, then close it again so as not to overflow your catch container.

At least you have measurable issues that you know are wrong that you can sort through. In other words, at least you aren't blind to the problem(s).

Brian

[Bill wjw]

Hi Brain,
I found a couple of copper washers that will work for shims to get the system pressure up. I put on two, but as per your experience I will take one out before testing again. I got brave enough to take the WUR apart. It is an interesting unit and I am beginning to understand how it operates. I have some very good technical help and tools to put voltage to the unit and watch how it works. I think I am going to have to knock the valve assemble up a little more out of the WUR body to lower the warm pressure. I will know more later in the day. I blew the valve out with compressed air them shot carb cleaner through it. There does not appear to be any obstruction. I will post what I find out.

[kodioneill]

Originally Posted by Bill wjw

Hi Brain,
I found a couple of copper washers that will work for shims to get the system pressure up. I put on two, but as per your experience I will take one out before testing again. I got brave enough to take the WUR apart. It is an interesting unit and I am beginning to understand how it operates. I have some very good technical help and tools to put voltage to the unit and watch how it works. I think I am going to have to knock the valve assemble up a little more out of the WUR body to lower the warm pressure. I will know more later in the day. I blew the valve out with compressed air them shot carb cleaner through it. There does not appear to be any obstruction. I will post what I find out.

You don't need to knock the pin up. Drill a hole in the center suitable for a 6x1.50 tap thread the hole then insert a bolt with a washer and nut so you can tighten the nut down to pull the pin up then, if you go to far you can tap the head of the bolt down to compensate.

[Bill wjw]

I added two copper shims to the pressure regulator in the fuel distributor. That brought the system pressure up to 72 psi. Cold control pressure was still hiht at 50 psi and stayed steady through warm up. I had taken the WUR apart last week and cleaned the screen and openings with compressed air and carb cleaner. The electrical function tested to specs.. I decided to try taping down the WUR pin. Gave it two wackes using a large punch and small hammer. The control pressure started in the correct range and rapidly climbed to 2.8 bars. That was right in the middle of the range for an 82 SC at the ambient temperature outside. The car now starts fine and warms up at proper rpm. She screams down the road now. No hesitation. It has been a lot of work fixing all the oil and vacuum leaks. New clutch and shocks. Even had to disable the faulty alarm system Friday. I am happy now and look forward to summer driving and a few trips north. Thanks to all who have helped me through this adventure.
Bill