Please help with my CO numbers!

[mrfatboy]

If I understand it correctly, the WRD internal spring is not totally compressed until full warm up, correct?  As the spring is compressed by the WRD feeler pin, the air valve is slowing closing the air intake AND leaning out the mixture.  If I start at a CO of 11% cold and it finally sits at 4% warm that suggests the WRD internal spring is not MAXED out (compressed) yet when cold.

On the flip side, let's say the spring was pre compressed at the stop pin and I had now where to adjust.  That would not explain the CO currently going from 11% to 4% during warm up.  The only other thing that is changing is the air intake is closing and if the internal spring is all ready compressed how would the FIP continue to lean out the pump to 4%.  It would get richer due to less air and the same fuel going thru the FIP.

Is it correct in saying that the internal WRD spring hits the stop pin (fully compressed) when the car is completely warmed up?  Before? After?

[mrfatboy]

I went ahead and preformed two more tests for a total of three to try to get the cold start better.  All three tests were stone cold starts.  My goal was to lower the CO% at warm up while raising the warm up idle hopefully to 1100.

My baseline stats were as follows:

-Cold idle 600-700rpm  (idle never was higher)
-CO started at 6% and immediately climbed to 11%
-Over a 4 minute period the CO dropped to 1.5-2%
-Drove car for final warm up and ended with a 4.0% CO with idle 600-700rpm




Test #1 

I removed the two shims under WRD in hopes of leaning out the fuel mixture during warm up.  Started cold and saw no difference in baseline.


Test #2

With the WRD oval shims still removed I added a 1.15mm shim UNDER the air slide valve in the WRD.  See picture below.  Started engine cold.

-Cold idle 600-700rpm 
-CO started at 6% and SLOWLY climbed to 11%
-After 4-5 minutes I didn't see any change in CO.  I assumed that I messed up and maybe the air slide valve got stuck or something.  I ended the test. 

I then took apart the WRD and found everything working correctly.  As I later found out, the time before the CO to start to drop was much longer.



Test #3

I decided to try a smaller shim under the air slide valve in the WRD.  I went with a .85mm shim.


-Cold idle 600-700rpm 
-CO started at 6% and SLOWLY climbed to 11%
-I decided to wait a while for this warm up to see if it would eventually come down.  It did.  It was noticeably longer than the baseline.
- Idle started to rise to 1000rpm over a long period of time.
- The CO eventually came down to 2.5% with an idle of 1000rpm.  I had to rev the engine a couple of times and it finally dropped to 650 -750rpm.
- Went for a drive and the CO retest was 4.5%

During the Test #3 drive I noticed that the car started missing a little again on hard acceleration suggesting it went a little leaner over all ranges.  Removing the oval shims and adding a round shim under the air slide valve would make mixture leaner but I thought it was only supposed to affect the warm up mixture. 

I found it interesting that none of my tests affected the CO during warm up.  The biggest difference seemed to be time.


I really wish I knew what the CO% was at cold start for a properly tuned car.  For all I know it really is supposed to be 11% and I am looking in the wrong place. Please jump in if you have the answer 



At this point, I have come to a dead end unless somebody offers a suggestion or another test to try.    It just might be that I can't compensate anymore for a worn pump. If not, I think I will call it day and just be happy what I have.

[twistedtree]

I think Dan said the same thing earlier in this or perhaps another thread, so I may be repeating.....

I would focus exclusively on tuning at full operating temp and get that working 100% first.  The only caveat is to ensure the WRD is closing completely when you do this tuning, but otherwise forget about the warm up cycle.

Next I would follow the BBB guidelines for adjusting the WRD internal shims to cause air shutoff to occur at the correct temp.  This can be done on the "bench" so to speak, though in my experience that means the kitchen.

And I wouldn't pay much attention to warm up CO.  I think it should be higher than normal, but as you point out, who knowns how much higher.  I'd be looking for a faster idle and acceptable running, then declare victory.

The challenge with the IP is that all the inputs are interrelated, but we don't know exactly how.  There is a stop for the WRD enrichment lever, but we don't know when it should be hit, nor do we have any good way to tell if it is being hit.  If that lever is not against it's stop, then the WRD presumably impacts mixture at all ranges.  It get very complicated very quickly, especially when it's a black box.

[mrfatboy]

Currently I'm fine with how it runs when warm.  I was just trying to get the cold start in spec while I am feeling motivated    I thought I understood from the other WRD thread that WRD pin DOES hit its stop when the car is warmed up.  Maybe I misunderstood. It makes sense that it would. You are absolutely right about everything being interrelated.  I have an extra pump on the bench that I check all the movements and measurements. There just so much you can do before all the interrelationships get out of whack.

The only other experiment I could try (short of putting a plexiglass cover on the side of the running pump to see what is going on) is removing the WRD completely and put an adjustable bolt in there.  That way I could check if the WRD pin truly hits the stop when completely warm.   Maybe I just haven't added enough shims.  I think the recess in air slide valve is about 2mm. Adding anymore shims would allow them to slip out.

[Garry]

Hey Fatty,

Nice to see you as a full member and welcome aboard.  Quite a few from Southern California now.

Garry

[mrfatboy]

Thanks.  BTW. I lived in Melbourne for a year when I was a kid.