WUR Adjustment?

[tstan]

I took Supermans advice for my cold start problem, "open the air box and start the car, when the engine dips pull down or lift up on the plate". Lifting up the plate brings the engine to a proper idle. OK, it's too lean on start up. My question is: is there an adjustment that can be made to the WUR or do I have to make the adjustment at the mixture screw? I'm afraid that if I make it at the adjustment screw it will affect the operation when the engine is warm. Right now when warm, it runs great. Any ideas?????

[makaio]

Stop whatever you are doing! Take it from me, before you start turning screws. Without a CIS fuel pressure tester gauge, you're just shooting in the dark. I learned this the hard way after putting in a new WUR when I didn't need to.

The CIS tester is $55 from JC Whitney, and the proper Bosch book is about $22. You need these things in you arsenal, before attempting any changes.

[Chuck Moreland]

Agree about the pressure tester comment.

The WUR is "sort of" adjustable, and it only affects cold operation. Once warmed up the WUR does nothing.

You can adjust the WUR by "knocking the plug". Unfortunately this method only allows you to adjust in one direction.

There is a method to make the WUR adjustable in both directions and Pelican has a tech article on this procedure. I did this and it works.

Read the tech article and you will then understand what "knocking the plug" is all about.

You really should have the pressure tester though. Without it your are just shooting in the dark.

You may not have a WUR problem at all. But unless you can see what is happening with the pressure, how will you know?

[wckrause]

Once warmed up the WUR does nothing.

That's not quite correct. The WUR always regulates control pressure, and will adjust it based on temp, throttle (vacuum), and atmospheric pressure.

Only the cold start control pressure is adjustable as stated.

[Sunroof]

The low and high pressures are adjustable for the WUR; however, after warm up its then you need to check the mixture. Everyone says go with a O2 sensor, but I just go by sound and feel these days. I do know that after warm up a jumping idle has indicated a rich condition so I have adjusted accordingly.

Remember, often their is some crap in that little 3mm adjustment hole so make sure you get that tool down in there well. What I have done is remove the air filter cover, held the sensor support arm in one hand and used the adjustment tool in the other (engine off of course). That way I get a good bite! RIGHT is RICH. LEFT IS LEAN. A click here a click there. I have become quite fond of that little tool and I should hang it around my neck on a lanyard!!!!

With the first CIS (1973.5) its like playing hide and go seek with this system. I guess thats what makes it fun with these older Porsches.

Regards
Bob
1973.5 T