Swinging Fuel Trims_Help!

[PhxTriode]

Oops I started a confusion above that I just noticed. Phx, your tune doesn't look half bad, despite the performance for your car, and above I was simply remarking that GM's tune looks like hammered Sh*t. My bad, anyhow um, taking it from the top sounds good starting with idle quality, and codes. Injectors should show up from there, BTW which injectors are they? I have data for 57Lb Bosch ZR1's, and 60Lb Bosch ZR1's. (Just got my 60's from FIC, mocked up a data stream from my 57's and they're fantastic.) 675RWHP they're at 76% IJDC, so 80 Lb may be a little big because I'm doing that with 12 Lbs of boost on a Silvy right now.

Stock ones should be the same as the ls9. On the CTS-V's we are maxing them out at close to 600RWHP I was at 110% IDC @ 6200rpm and 11.6 AFR before punching them. Wacky thing is the 80"s show 75% at WOT and -.5% AFR error on my NGK/NTK. Not sure if I trust the scanner's IJDC anymore (the math is right provided the pulse width is accurate)

[IDRIVEAG8GT]

Yeah buddy unless something got messed up if the tune was improperly scaled. Did you check the Cats though?

[PhxTriode]

Yeah buddy unless something got messed up if the tune was improperly scaled. Did you check the Cats though?

Injector data was scaled based on 80.14lbs/hr@58psi which is what the company that did the injectors said the flowed.

[IDRIVEAG8GT]

Might wanna see if you can get your fuel pump to hold a solid rail pressure at idle. If it changes every now and then, injectors get pissy especially with inaccurate data.

[PhxTriode]

I found something crazy today.

I pasted all of my MAF data in a spreadsheet from current vs stock, then my current vs another CTS_V with the same mods and my lbs/hr are 50% higher than both with either injectors in (stock or #80's). What the hell would cause that???

I have already replaced the O2's and MAF. I have replaced every single gasket MAF o-ring, TB, SC lid, intake...

I sprayed everywhere there is a mating surface with MAF cleaner and no idle change.

Not one code either.

WB AFR error % matches STFT. I am so frustrated

[IDRIVEAG8GT]

???? I think it is time to ask C.U. or Steck????

[DSteck]

Don't have my laptop with me... But for starters, throw the drilled injectors in the trash. If you want huge injectors, get some new ID850s. They are direct drop in and have low pulse performance that is unmatched... Perfect for a returnless fuel system. PM me for more information. Drilled injectors are for scrubs.

Log your Inj Delta Pressure. I'm pretty sure the CTS-V has that. You could be getting interference from evap purge, which will cause trims to go way negative. Log the fuel trim cell. I'll try looking at your injector data. If it is having problems with big injectors, I'd say it's a case of a crappy injector. If it's having trouble with stock injectors, then something else is amiss. I'll try to check the tune when I can.

[PhxTriode]

Don't have my laptop with me... But for starters, throw the drilled injectors in the trash. If you want huge injectors, get some new ID850s. They are direct drop in and have low pulse performance that is unmatched... Perfect for a returnless fuel system. PM me for more information. Drilled injectors are for scrubs.

Log your Inj Delta Pressure. I'm pretty sure the CTS-V has that. You could be getting interference from evap purge, which will cause trims to go way negative. Log the fuel trim cell. I'll try looking at your injector data. If it is having problems with big injectors, I'd say it's a case of a crappy injector. If it's having trouble with stock injectors, then something else is amiss. I'll try to check the tune when I can.

Stock injectors posed the same issues after looking at my tune when they were in. I have logged delta pressures RPM VS ECT (attached image).How do I test for EVAP Purge. The ID850's you spoke of, do they make smaller one's? I based my INJ size off of the now bad data (MAF out of wack) of IJDC. My target moving forward is 650rwhp@6500rpm and 11.6AFR

Thanks for peaking in on it.
First attachment is Delta Pressure, second is STFT vsMAF, and the third is WB err vs MAF.

[DSteck]

You're saying LTFTs are changing drastically, correct?...

The pressure at idle is subject to change. The variable pump will try to float at a target, but will never hold it perfectly steady.

[IDRIVEAG8GT]

His trims swing deviously at idle. Its like what a SBC will do with a plugged fuel filter.....