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A/F ratio tuning
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Jan 26, 2021 4:13 pm    Post subject: A/F ratio tuning Reply with quote

I put a new fuel pump in that actually puts out enough PSI (a 944 pump does NOT, and the one that came in my car from a ford ranger/aero start/generic, almost put out enough, but still short)

So I hooked up my gauge and was getting up to 85 psi, but with the valve open or closed there wasn't much change. I was starting to think the WUR was bad, But I tapped the diaphragm/banjo bolt block down a little and that seemed to do the trick.

NOW note I have a easily adjustable WUR (I'm making a YT vid on it) so I can easily adjust the Pin/dowel of the thermal plate up and down at will and finitely.

I got it so the idle A/f was 13.5-14, but then once I started driving it started to lean out under boost toward 15-16, pulled over and enriched the CIS meter.... drove again, now its way too rich! idle around 13, but on boost going to 9!!! engine stumbling on boost.
WTF??

pull over again, and now the engine is idling around 10-11.(with out touching anything yet) I lean out the WUR (pull pin upwards) (no pressure gauge on at this point) and as soon as I move the pin up just a tad, the RPMs go up.

idle is now around 14, drive again, WOT still hitting high 9's

Last try: I lean the CIS meter slightly, and now Im getting WOT/boost reading of around 10, still seems a little rich.


The tricky thing is, if you adjust one (WUR) you have to adjust the other (CIS meter) and then of course adjust the idle speed as this affects your idle A/F.

But now that im close, and I feel like I want to enrichen the Boost A/F slightly do I do it with the WUR or the CIS?

(in case it wasn't obvious I've messed with everything every which way, and the low pressure fuel pump, threw me in a wrong direction, so I had no real base setting, and when you have 4 different variables it make things a pain)

All in all I drove around for about 30 min, and on my last turn before getting home I had some idiot in an A4 race me! I didn't even know it, I was giving it some gas to test the car out and I notice the car beside me trying to keep up! BUT I"M IN THE TURNING LANE YOU RETARD!!

Also when I got home, went to wash my hands in the kitchen sink, I thought "what time is it?", turn around to look at the clock on the stove: and it's 9:24... no joke!
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morghen  



Joined: 21 Jan 2005
Posts: 8338
Location: Romania

PostPosted: Tue Jan 26, 2021 5:32 pm    Post subject: Reply with quote

Your wur is probably bad.
Especially running higher boost than factory, it is regarded as normal to idle at 13.6 and get as low as 11 under full load in mid rpm and then lean out towards top end rpm.
I was running 1.1bar, had it idle at around 13AFR, would go down to low 11 or even high 10AFR at 4000RPM and then lean out to 13 at 6500RPM under full load.
That leaning out wasnt particularily great as it would produce detonation but you get the picture of what the WUR should do.

I would disregard the idle afr for now and adjust the WUR so that its running mid to high 12AFR at top end RPM and full load.
Then see how the mid range looks...if its 11.something it should run fine.
And then adjust the idle to your liking.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Tue Jan 26, 2021 5:59 pm    Post subject: Reply with quote

Well, from all the adjusting i've done, the best way I can think about it, is the CIS does the overall mixture, but the WUR controls the enrichment curve.

Now that I have had a minute to think about it, I think the next adjustment I need to make is slightly lean the WUR, and then maybe richen the CIS a hair.

If Im correct that will lean out the WUR control at WOT.


Unfortunately right now my RPM gauge doesnt work, and neither does the spare I have, even though Im getting a pulse.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2194
Location: Somerset, UK

PostPosted: Tue Jan 26, 2021 7:22 pm    Post subject: Reply with quote

http://930wur.com/

Pissing in the wind with a stock wur trying to get all AFR in spec.

Also don’t forget as soon as the boost signal hits the wur, it will go super rich before full boost and rpm needs it
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Cdric  



Joined: 27 Aug 2004
Posts: 2114
Location: Sweden

PostPosted: Tue Jan 26, 2021 8:44 pm    Post subject: Reply with quote

I dont remember how modified you car is, but i think it would probably be best to try and come back close to factory settings. I would start by setting the CIS system pressure according to the specs and then not touch the fuel distributor.

'You can change the warm control pressure on the WUR, and the maximum boost enrichment allowable, and thats where i would start.

I run at 1 bar with more or less standard everything, and it works well, my biggest issues is exhaust pops/bang after throttle lift of. But ive noticed that not all wurs behave exactly the same, and of course not all modded engines are the same. So fine tuning is always needed.

One thing I did last year was to just unhook the boost enrichment boost port from the wur and just let it hang, that helped alot to get rid of the rich midrange, while minimally affecting the top end. But if you have a standard car without IC than leave it on, the standard car should have a very very flat AFR curve.
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Wed Jan 27, 2021 12:18 am    Post subject: Reply with quote

If you are running the lambda system you need to tune to the lambda system with a dwell meter, or you could be idling 14.7 but still be rich or lean quite a bit on the afr screw..

Or unplug your o2 sensor and then tune to 14.7 with it unplugged..
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Wed Jan 27, 2021 6:14 am    Post subject: Reply with quote

Carrera RSR wrote:
http://930wur.com/

Pissing in the wind with a stock wur trying to get all AFR in spec.

Also don’t forget as soon as the boost signal hits the wur, it will go super rich before full boost and rpm needs it


I've already converted it to adjustable, and rebuilt it.
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Carrera RSR  



Joined: 08 Jan 2010
Posts: 2194
Location: Somerset, UK

PostPosted: Wed Jan 27, 2021 6:44 am    Post subject: Reply with quote

MikeDanger wrote:
Carrera RSR wrote:
http://930wur.com/

Pissing in the wind with a stock wur trying to get all AFR in spec.

Also don’t forget as soon as the boost signal hits the wur, it will go super rich before full boost and rpm needs it


I've already converted it to adjustable, and rebuilt it.


Are you adjusting the hex nut under the brass cup on the bottom of the WUR? As seen on the left

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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Wed Jan 27, 2021 6:46 am    Post subject: Reply with quote

C�dric wrote:
I dont remember how modified you car is, but i think it would probably be best to try and come back close to factory settings. I would start by setting the CIS system pressure according to the specs and then not touch the fuel distributor.

'You can change the warm control pressure on the WUR, and the maximum boost enrichment allowable, and thats where i would start.

I run at 1 bar with more or less standard everything, and it works well, my biggest issues is exhaust pops/bang after throttle lift of. But ive noticed that not all wurs behave exactly the same, and of course not all modded engines are the same. So fine tuning is always needed.

One thing I did last year was to just unhook the boost enrichment boost port from the wur and just let it hang, that helped alot to get rid of the rich midrange, while minimally affecting the top end. But if you have a standard car without IC than leave it on, the standard car should have a very very flat AFR curve.


this car is pretty much stock at the moment. the only thing I'm not sure about, is I have 3 WUR's one is from an s1 (my car is an s2) I don't recall which one I have in it right now (with the adjustment mods)
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Wed Jan 27, 2021 6:53 am    Post subject: Reply with quote

No, im adjusting the pin that holds the Bi-mettalic strip
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Fasteddie313  



Joined: 29 Sep 2013
Posts: 2224
Location: MI

PostPosted: Thu Jan 28, 2021 12:16 am    Post subject: Reply with quote

I think the strip is supposed to be completely off once it’s up to temp.. That’s for adjusting cold control pressure, when cold only..

You can adjust warm control pressure by tapping the diaphragm cylinder in and out of the housing.. The round thing that the lines bolt into.. It moves in the housing.. Tap tap tap with a hammer.. Put it back together, test warm pressure..

Take that diaphragm all apart and clean it while you’re at it..

Hex nut under the brass cap is for adjusting the on boost control pressure I’m pretty sure..

I never got that far into setting WURs before I got rid of mine completely..

Definitely need to take your lambda into account when setting base AFR though..

I have a good WUR if you need it..
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Fri Feb 26, 2021 7:58 am    Post subject: Reply with quote

Damn, where did I screw up?
I pulled the WUR off and took the bottom cap off and punched a hole in the brass cap to adjust the Boost enrichment... But now that doesn't even matter, I cant even build boost!
Took it for another test drive yesterday and it was barely driveable.

Its running so rich at part throttle down to 9:0 its starting to stumble, but at idle (once it warms up) its going way lean, 18:0+ (sometimes up to 22:0)

So what I can't figure out right now (my brain has been rattled by the stock market, can't think things out 100% at the moment; the car is supposed to be a tinker toy escape) is where to focus on.

At first as mentioned in my original post it seemed to be running mainly ok, except for the boost enrichment... well after I messed with it, Now it swings from way rich to way lean after it warms up. (example: I turn the car off after its warmed up, start again after about 10 min, start around 10-11:0 AFR....then as it warms up over the next 2min, it starts to go very lean toward 15-17 (so Im assuming this means the Heating element in the WUR is working)

I tried leaning the CIS but that only brought the AF on part throttle to 10, but made off throttle near 20. SO I richened the CIS and leaned the WUR, which helped a little but the range was still too extreme.


Now I had tapped the Fuel port block on the WUR in about 1mm previously when I had my last "incident" but when I took it apart to punch the hole in the Brass cap, I tapped the Port block back out, but that seemed to make little difference(I thought tapping it in would decrease the boost enrichment) Maybe I need to tap it back out some more??
The car has a new fuel pump BTW.

so I have both "adjustablilities" done to my WUR





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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Fri Feb 26, 2021 8:34 am    Post subject: Reply with quote

heres the pic of my "easy adjust" WUR set up



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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
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PostPosted: Fri Feb 26, 2021 8:55 am    Post subject: Reply with quote

I feel like I'm starting to juggle too many variables at once.
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MikeDanger  



Joined: 21 Nov 2002
Posts: 636
Location: Denver

PostPosted: Fri Feb 26, 2021 9:28 am    Post subject: Reply with quote

morghen wrote:
Your wur is probably bad.
Especially running higher boost than factory, it is regarded as normal to idle at 13.6 and get as low as 11 under full load in mid rpm and then lean out towards top end rpm.
I was running 1.1bar, had it idle at around 13AFR, would go down to low 11 or even high 10AFR at 4000RPM and then lean out to 13 at 6500RPM under full load.
That leaning out wasnt particularily great as it would produce detonation but you get the picture of what the WUR should do.

I would disregard the idle afr for now and adjust the WUR so that its running mid to high 12AFR at top end RPM and full load.
Then see how the mid range looks...if its 11.something it should run fine.
And then adjust the idle to your liking.


So Im running stock boost, the gauge is reading about 6-7psi.
Problem is if I lean it out to run 11afr on boost it would be supper lean off throttle, I actually had the engine die for a moment as I slowed for sharp turn.
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