WRD Slider Valve Cold Start Position?

[mrfatboy]

Today I had some time to play around with the WRD to see if I could alleviate a rich cold start issue.  At at stone cold start I used the split linkage test and determined the car is running rich during warm up.  At operating temp the fuel/air mixture is perfect and the car runs great.  It's just the first minute or so during warm up it could run smoother(need higher rpms).

CSV doesn't leak, new plugs, new injectors, timing, etc is all correct. FIP air filter not clogged.  FIP air valve shuts off completely at operation temp. FIP was tuned at Fairchild.

My first attempt to lean out the rich condition at cold start/warm up was to remove all oval shims under the WRD. My understanding is this should lean out the FIP only during cold start/warm up.  I think it helped a tiny bit but the split linkage test reveals it is still running rich.  I still need more air.

Since everything is set correctly when the car is at operating temp(used CO meter to verify) the issue must be at the WRD. I don't want to monkey with leaning out the pump over all ranges using the BC adjustment method or adjusting the rack screw at this time because that will also affect the FIP at operating temp which I don't want.

The next step was to remove the air hose from the WRD to eliminate the slider valve shut off position entirely.  This had a major LEANING effect.  The car was now running lean as determined by the split linkage test.  Progress is being made

So now comes the big question. Does anybody know where the slider valve should be within the WRD at stone cold start?  I have attached a picture.  Using a mirror you can see that my valve (aluminum sliding cylinder-  RED arrow) starts VISUALLY about 50% closed. This could be correct.  I don't know. The blue arrow points to what looks like a metal pointer within the WRD air housing.  My valve lines up to it at stone cold start.  Is this where it supposed start? Coincidence?

At this time, the only way I can think of to get more air into the system during cold start/warm up is to adjust the two nuts (toward the bulb, tighten) on the thermostat bulb in the WRD upper housing thereby having the slider valve start more open.

I hope I was clear.  Before I move forward I would like to hear what you guys think.

[mrfatboy]

Today I opened up the upper level of the WRD that houses the thermostat bulb to see if I could make any adjustments. When I saw the bulb I realized it was the newer preset type (I forgot. it's been awhile).  There are no nut adjustments on it.

However, I did have an old working thermostat bulb with the nut adjustments on it and I thought I would swap it out with my new test adjustments.  I adjusted the nut toward the bulb so that the air slider valve would be more open at cold start.

Short story... my test was a failure   I put everything back the way it was.  The only good thing was that I got a FIP/WRD refresher  

[wwheeler]

You can adjust the air valve so it "just" closes when warm by the round shims. By removing the round shims, the air valve will be more open when cold, but you also add fuel. So that will only raise your idle speed some when cold and will also extend the time the WRD is on. Make sure as you know, that the air flow shuts off completely when warm. I do not know of an easy way to increase air in the A/F ratio in the WRD other than the oval shims, as it is set by design.

[mrfatboy]

By removing the round shims, the air valve will be more open when cold, but you also add fuel. So that will only raise your idle speed some when cold and will also extend the time the WRD is on.

Correct. It's all starting to come back to me now It's so confusing with all the permutations of adjustments that can be done.

When I started this little tweak test my original thought was to just increase the air without changing fuel.  In order to accomplish this I would have to remove the round shims (more air and fuel) AND remove the oval shims to compensate for the added fuel, correct?

[wwheeler]

In order to accomplish this I would have to remove the round shims (more air and fuel) AND remove the oval shims to compensate for the added fuel, correct?

Removing round shims will raise your idle speed slightly just because you are adding both fuel and air. That won't change your mixture though. And as you know, there is a limit to how many round shims you can take out (WRD won't close). It sounded like you were badly rich at a cold idle. Just removing oval shims by itself will lean the mixture and accomplish what you are after. I also remember that you said you had already removed all of the oval shims. So at this point, I am not sure how you can increase the air without adding more fuel. Almost sounds like there is a restriction somewhere in the air circuit not allowing a correct amount of flow. Maybe others could help with solutions?

You could also test with and without the FIP air filter to see if the mixture leans out significantly. If it does, then the air filter is bad. Short of the oval shims, the A/F cold mixture is set by the WRD device and cannot be changed unless you alter the air slot opening in the air valve cylinder or such.