Assembling the WUR
 

About a month ago I took apart the WUR for cleaning. By mistake I assembled the bimetallic strip upside down and ran the car a few times. Needless to say, the car ran like crap. I have since rectified my error. The strip appears undamaged, but poor running issues make me wonder if I did damage it. Thoughts?

Testing WUR.........
 

911nick,

You need to test and measure your control fuel pressures using the correct gauge. Without knowing the fuel pressure readings from cold to warm, you can not tell. The first 4 mins. is critical. Post these values.

Unless you broke the heating element, the bi-metallic spring is very sturdy. BTW, what problem/s are you having with your CIS? Keep us posted. Thanks.

Tony

Hi Tony. Outside temperatures have been about 55 degrees. Starting the car cold, it seems to run on less than 6 cylinders. It takes about a minute for the idle to get smoother. It does not idle high like it should during cold starts; it goes real low. The idle increases as it warms. Once warm, it idles nicely, but I'm getting a lot of exhaust backfires on deceleration. I just installed headers and a free flowing muffler, so this probably exacerbates the situation. However, it runs rich for sure. There is also a midrange stumble. I've eliminated vacuum leaks. There is a bit of a drop in rpm when I remove the oil cap. New plugs, wires, fuel filter, air box, cap, rotor, serviced the ignition distributor. I have my gauges setup right now. I will take readings later today and post. Oh, my car is a European model equipped with the 69 WUR. It reads 36 ohms cold.

I just took some readings with terminals 30 and 87a jumped.

WUR resistance is 37.7 ohms (I stated 36 ohms earlier)
I measured 10 volts at the plug that goes to WUR
Cold control pressure - 2.5 bar
Warm control pressure - 2.5 and no change. Ended test at 2 minutes.

Something to note is I replaced the o-ring inside the WUR last night. The new ring is a bit thicker than the old one. With the WUR dismantled, I can get forced air and carb cleaner through the inlet and outlet. But, once assembled, I cannot feel air going through. I would have thought that air would be able to pass through, especially when the WUR is cold.

Update:

I knocked the plug until the gauge read 1.5 bar cold control pressure (CCP). Afterwards, I applied power to the WUR for a warm pressure reading. After approx. 2 minutes, the gauge read 2.5 bar, and it seemed to hold.

What do you think of these readings? Should CCP be 1.0 bar? How high should the warm pressure be after 3-5 minutes?

Control fuel pressure chart........
 

911nick,

You will need more than two (2) mins. to do the test. A good WUR-069 would get to WCP about 4 mins. Your WCP should be around 46 ~ 53 psi. BTW, I prefer to use psi. because that's what I've been using ever since. Something you have not demonstrated is the fuel pressure difference between NO VACUUM and W/VAC.

Use a hand vacuum pump and check the difference. I looked at my logbook and checked the WUR-069 calibration I did last month. My record shows that after 2 mins. WUR was heated it was about 80%~90% of specified WCP. This also similar to other WUR's used in CIS applications.

Your cold idle engine speed (RPM) should start HIGH and gradually goes down as the control pressure builds up. Your engine is exhibiting the opposite. You have more problem to solve aside from your WUR.

Tony