Air fuel code for scangauge

JvKintheUSA

I have been trying multiple codes for the Scangauge II, so I can measure my A/F ratio, but had no success. Has anyone had any luck getting the Scangauge II to display the A/F ratio. I tried Google but no luck.

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Modshack

Someone here claims to have done it, but I followed his info and could not get it to work on mine, and I've done a fair amount of SG code entry...

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JB1

That was me. I used the "Alternate A/F Ration (general)" setting for CANSF. See page 3 in the XGauge list: http://www.scangauge.com/support/pdfs/XGAUGE.pdf

It works on mine, I do get an A/F reading. It normally is between 13.7 and 14.7. These look like fairly normal A/F ratio's (rich to stoichiometric) so I assume this means this setting works correctly on my Scangauge.

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Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar //

JvKintheUSA

I'll try that setting and report back in a few. I see you are rooting for Holland - I like!

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JvKintheUSA

+1 for you JB1 - it worked. Shows me an A/F of 14.5. Is that good, bad or ugly?

Edit: I did a quick highway run and the A/F ration varies from 0 (downhill no accelerator pushed) to 17.5% at full throttle, but most of the time is around 14.5%. So I guess the 17.5% is quite lean. Not sure if that is normal.

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Modshack

Normal A/F will remain in the 14.5 to 14.7 range as long as you're in closed loop (partial throttle mode). When you cross over to open loop (WOT), mixtures should go rich not lean. YOu can set the Scangauge to show the transition. If that 17.5 is accurate it is dangerously lean. Ideal full throttle A/F should be in the 12.5-13% range.

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Steal my car! (SOLD)...Now Porsche Cayman S
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Nick911sc

I'm glad to know this worked out. When I get around to doing any mods to my car I plan on buying this!

And please check your A/F ratio! It would pain me to see someone on the forum grenade their engine from being too lean.

JB1

Thanks for the rep. I'm Dutch so yeah, go Holland! I hope this will finally be our year

I just noticed your custom title, funny, I'm about to order a set of "DUTCHZ" vanity plates, I bet it will add at least 50hp

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Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar //

JvKintheUSA

Yeah I felt the difference as soon as I put my plate on!

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JvKintheUSA

I'll be monitoring it closely - tonight on my way home i will floor it a couple of times and re-check the A/F ratio. Wonder why that would happen though...I put the stock intakes back on, which would presumably give me less air and a lower A/F ratio - correct me if I'm wrong. But then again, doesn't the ECU compensate for that automatically? I guess that when in you are in open loop everything the ECU does is out the door and it is max fuel and whatever air she can breath.

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Nick911sc

The ECU does not compensate for Intakes, so when you had the R2C's on it will not compensate I believe because of the different size tubing and all that MAF mumbo jumbo. Someone else can answer that better than me because I'm not expert.

JB1

Why did you put the stock intakes back on? Because of the a/f ratio or something else? I had Takeda intakes for a while but got rid of them because of the high air intake temps. (sound was great though). If I remeber correctly, a/f ratio with the Takedas was mostly in the 13 range, so rich not lean.

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Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar //

JvKintheUSA

The reason I took them out and put the stock back in is that I wanted to see the difference in air intake temps. Also I will be doing another dyno run in the next few weeks with the stock intake and maybe I'll do it also with the HKS Super Hybrid drop-ins I ordered. I might also order the Cobb post MAF hose as well - not sure yet. I know some folks wanted me to throw the R2Cs back on after I dyno with the base intakes, but not sure if i can make that all happen. In all honesty - I have not noticed much of a difference, if any. The intake temps with the R2Cs installed while cruising at highway speeds were about 6-8 above ambient - same results with the stock intakes. The main difference is that the intake temps while stopped, do not climb as fast with the stock intakes - they also fall faster with the stock set-up. I did not have the code to measure the A/F ratio with the R2Cs, so not sure what it was before, but only WOT I measure now 17.5-18.1 A/F ratio, which scares me a little.... Not sure why the car would run so lean with the stock intake. Maybe it has something to do with the HFC and CBE I have...

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JB1

Well, for what it's worth, until 3 weeks ago I had Berk HFC + Berk CBE and stock intake with Cobb post MAF hoses. As far as I know I never saw the A/F ratio go over 14.7. Since then I swapped the Berk HFC's for the stock cats and the A/F ratio remained the same. But I'll pay more attention tomorrow during my drive to work to see what the A/F ratio does during WOT. I'll report back later!

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Black Fangs // Black rear Valance // Berk CBE // COBB post MAF tubes // K&N drop in filters // Setrab Oil Cooler // Stillen Sway bars // Z1 SS brake lines // Stillen brake cooling kit // Harness bar //

Jordo!

Is that a transformed value derived from the narrowband O2 voltage? In closed loop, all the ECU cares about is seeing the O2 hover around .5 volts (i.e., ~14.68 AFR / lambda = 1.0).

There's pretty much no way it can run too rich or too lean in closed loop (fuel trims will correct) unless something is really fvcked up, in which case you'll get a CEL.

In open loop the AFR will be whatever was tuned from the factory without the narrowband commanding any adjustments (except probably for a long term trim that carries over that is).

Say what? Is that a sustained AFR or only an occasional blip (e.g., going lean on tip-in)?

If you are seeing stable AFR's that lean under heavy load (i.e., WOT, high RPM's) GET OFF THE THROTTLE! You may very well get massive detonation and kill a piston or spin a bearing in short order.

Assuming that value is accurate -- best to confirm with a good wideband O2 either on a dyno or one you can buy (e.g., AEM UEGO)

You do not want to see anything leaner than ~13.5 under heavy load, N/A and a bit richer would be preferred for best power.

Especially if you are using 91 AKI instead of 93... with 93 anything south of stoich is probably okay (N/A), though not best for safety or power.

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