LSA CTS-V holding good A/F until 3rd/4th gear, then spikes rich..

[That_guy]

First guy that tells me what my problem is and it actually fixes the issue gets $50 via Paypal gift.

Car is making about 16psi on the stock blower. Has full bolt ons and a 226/240 camshaft. Car runs great, MAF correction error is +/- 3% all the way through the hz range. When this thing hits the top of 3rd and going into 4th it goes from a good commanded Air/Fuel down to 10:1. WTF m8?

Some thoughts:

Car has FAST 85lb injectors that were checked by FIC and showed to flow very good & accurately. They were 940cc @ 4bar. Take a look at the injector data too and let me know if this is causing my issue.

I've played with cat over temp thinking this could be my issue. Even when disabled it still goes rich.



Thanks

[Russ K]

Your not logging the commanded AFR. But you still have the COT enabled and the Cat test & post O2 tests need to be disabled. And I would lower the WOT timing by 2* to start with to lower the knock retard.

Russ Kemp

[supercowboy]

looks like you pulled fuel from the maf table to compensate. I would shut of cot so that doesnt make changes. need some more data. datalog commanded afr in fuel settings make sure power enrich is working correctly. Also data log fuel pressure to make sure fuel is not rising causing too much fuel, also monitor torque management. car looks like it pulling timing do to this. When the car pulls timing makes less power but fuel stays the same cause a richer condition. you might have another issue going on that can cause that.

[b2009v]

COT will certainly cause a similar situation.

[SultanHassanMasTuning]

if you still have cats, you can still have it enabled but lower the enrichment multiplier say stock is 1.35 (change to 1.1)

[That_guy]

Thanks for the input gents. I'll get some more logs tomorrow and post them up.

[That_guy]

Ok guys, here's 2 runs. They're not the greatest, but I do have commanded Air/Fuel on there. The first run wasn't as long as I'd like because I have to be careful, I'm doing this on public highways. Second run I had a lot of spinning on the 2-3 shift.

Basically it's super lean through second and then literally richens up a full point in every gear. By the time I hit 4th I'm in the 10's on Air/Fuel.

Any input would be appreciated. Thanks!

[SultanHassanMasTuning]

config? are you logging fuel pressure? you do know that the system purges and gives variable pressures...

[That_guy]

Sorry. Config is attached.

Did not know they had variable fuel pressures. How much power can the stock CTS-V pumps support?

Thank you

[gmtech16450yz]

Like guys have said, disable COT. I also noticed that your "Low Flow Fuel Pressure" is at 36.3. Not sure what stock is in your '09 file but the later LSA files it's at 50.8. I doubt that will fix your issue but double check against your stock file and make sure it's the same.

You might want to try this config file of mine. Everybody has their own scanner setup preferences but this one shows a lot more of what you need to see than what you're logging and charting. You'll have to add in your custom PID for your wideband though.

Speaking of the wideband, are you sure that wideband is setup correctly and the voltage offset is right? It's a little weird that your wideband gradually reads richer, but at the same time your narrowbands are going leaner. (Yes, I know all about narrowbands, but they do tell you something even on the extreme ends.) Your narrowband starts out at 9.4 and goes to 8.6. At the same time your wideband is going richer, not leaner. That may be telling your something. Over a run like those, and especially with the afr supposedly going to 10.xx, the narrowbands should be well over 900mv.

Here's my config, enjoy!

("Sky LSA" is the one you open in the scanner, "VCM Scanner" is the one you put in your "Settings" folder. Save your "VCM Scanner" file somewhere else if you want to go back to your setup later.)