What areas does adjusting the WUR pin affect? AFM screw?
 

Basically wondering if adjustments to WUR pin and AFM screw affect all areas of fueling, or just idle or other specific conditions.

I’ve been slowly sorting out a car I bought which has a 3.3 turbo motor swapped into it with seemingly all necessary supporting accessories. It has had some ups and downs with how it’s running, but think I’m making progress.

WUR is a 153 part number, and I believe the fuel head is stock but if there’s a way to verify or check these or other important components please let me know.
I have a wideband and boost gauge installed, as well as a manual boost controller.

I took apart the WUR, cleaned it up, then adjusted pin height. Months ago when I did this I was able to get all pressures in spec, barely, but now CCP is reading lower and I’m not sure why, but car still starts and runs fine.
Currently, system pressure is 6.9 which is correct. CCP is 1.5 which is .4 low, but WCP is 4.0 which is just a hair high.

With these pressures and how the AFM screw is currently set I am seeing:
11.0 AFR at startup, quickly climbing to…
13.2 AFR after a couple minutes idling
13.2 AFR steady idling
13.2 AFR cruising
10.5 AFR in boost, about 10 psi currently

So… it works, but it’s not perfect.
I don’t want to touch this without being clear on how to make improvements.

Can someone explain what adjustments to WUR pin height and AFM screw affect? I’ve read different things and want to be sure.
Or are there any other adjustments I should be looking at?

If I can lean things out a bit all around that should be an improvement, but I want to learn and understand first before doing.

You can go here and click on the CIS Primer for educational info:

https://rarlyl8.com/

The pin you are referring to adjusts CCP only (cold control pressure).
The idle mixture screw will fine adjust the WCP (warm control pressure) but also affects all other parameters to a lesser degree.
Your AFRs look acceptable for everything but cruising which should bump 1 unit higher than the AFR at idle. This is unusual. Double check for vacuum leaks.

Thank you, so since my CCP is low I could raise the pin slightly (or leave it if it’s running ok), and no other impact of adjusting that?

Sounds like I could turn the idle mixture screw a bit leaner and it might move me slightly in the right direction?

10.5 AFR at 10 psi of boost could be .5 to 1.0 leaner as well, couldn’t it? Currently at 10 psi but would like to be at 12-14 psi up here in the mountains of CO if everything else is under control.

I smoke tested earlier this year and found no vac leaks.

Optimally all of the fuel pressure settings would be within the spec range, but it is more important that the engine runs well. System pressure sets and moves all the baselines so that has to be in spec as does voltage to the fuel pumps and all the associated wiring fuses and relays. Adjusting outside of spec range is typically done due to sub-par performance of the components.
It sounds like your WUR may be getting lazy and not fully leaning out as the engine warms. Measuring system pressure and cold/warm control pressure will help verify. The engine AFRs at idle should automatically jump one point at cruise, no adjustments needed.

I'd definitely second what Brian says about "more important that the engine runs well".

It's way too easy to focus on the numbers and not the result. I know I've been guilty of trying to chase perfect pressures and AFRs when, honestly, who cares what the number is if it runs well.

I've often screwed myself up by chasing that decimal point when I should have accepted it because it runs great.