Stock LS1 with Stock Tune - Lean Codes

[MathGreek]

I swapped a stock 5.7L LS1 with new gaskets/seals out of an 04 GTO into an S10 and have been getting P0170/P0174 lean codes. The codes usually show up for a couple of days then turn off for a couple of days and repeat. Fuel pressure is around 58-60psi at any rpm and I can't hear any exhaust leaks. I've been doing some logging and I noticed my IATs were getting very high (~145 F) sitting in traffic so I thought that might be causing it to go lean. After relocating the sensor out of the path of the radiator fans, the code still came back after a couple days. Also, it seems like it only goes really lean around 1200-1800 rpm (low throttle) if I'm reading the O2s correctly. I'm new to HP Tuners so I'm not really sure what readings are normal and what aren't so I've uploaded a log file from my morning commute if somebody can take a look.

Only differences from a stock 04 GTO:
04 GTO K&N Cold Air Intake
98-99 Camaro exhaust manifolds w/ EGR/AIR pipes cut/welded
LS7 lifters
LS2 timing chain
LS6 oil pump
3.08 gears (came with the truck)

Thanks

[Frost]

When the MAF is moved from it's OEM piping into a new position, the old transfer curve is no longer accurate. IYour long term trims show learning of +15 to +20%. Most OS's will trip that code around 20% out. That's a lot of error to make up wiith trims. Either tune the MAF or fail it to SD; it should run on the OEM VE with less positive trimming.

[MathGreek]

I'm using a K&N air intake for an 04 GTO so the MAF should be in the position expected by the stock tune. If it matters, I'm using exhaust manifolds from a 98-99 Camaro which supposedly flow a little worse than the GTO manifolds. I'll add this info to my original post. When I get a chance, I'll disconnect the MAF and see if the LTFTs decrease while in SD.

[mbray01]

the point Steve is trying to make is, you have the engine outside of the stock parameters. touch up the maf curve, and make it happy. you either have a mechanical issue, or a tuning issue. either the parts are incorrect or bad, or the tune is incorrect

[blindsquirrel]

I've told this story before so I apologize if anybody experiences deja vu...

Dealership, new unsold Chevy HHR was sent round to the service dept with a CEL on, P0171 FT System Lean, no other codes. Clear codes & drive for HOURS, no code. Let it idle for ~20 minutes and get P0171 again. Swapped O2 sensor, no change. Swapped MAF - bingo, no more code. Inspected the MAF and found the tiniest little sliver of plastic flashing curled around one of the support bars in the MAF, and not right close to any of the critical bits, either. Removed the debris, reinstalled the original MAF, no more code.

Point is, it only takes a tiny disruption to skew things and adding a CAI without retuning anything is a much bigger change to the airflow tract than a little 1/8" long sliver of plastic.

[vettemakesemwet]

I've told this story before so I apologize if anybody experiences deja vu...

Dealership, new unsold Chevy HHR was sent round to the service dept with a CEL on, P0171 FT System Lean, no other codes. Clear codes & drive for HOURS, no code. Let it idle for ~20 minutes and get P0171 again. Swapped O2 sensor, no change. Swapped MAF - bingo, no more code. Inspected the MAF and found the tiniest little sliver of plastic flashing curled around one of the support bars in the MAF, and not right close to any of the critical bits, either. Removed the debris, reinstalled the original MAF, no more code.

Point is, it only takes a tiny disruption to skew things and adding a CAI without retuning anything is a much bigger change to the airflow tract than a little 1/8" long sliver of plastic.

Ford expidition, mid to late 2,000's model. Customer complaint of sometimes a long crank/hard start. No codes, no PID out of range, NOTHING. COuld not duplicate. Did everything except put it in a climate controlled booth to super heat and deep freeze the damn truck. Nothing. Fired right up for days in our shop, boss driving it, me driving it, the old codger of a porter driving it, all kinds of scenarios to create the long crank. Bring it in my bay to do something, was running, started stumbling, died and became a crank no start. Watching the scan tool, saw MAF dropping out. Pulled the MAF and found a char-broiled, electrified, shriveled, dried up carcass of what was left of a bee. Gently removed said carcass and wished it well in its next life. Truck has no more issues. What really tweaks my melon, how in the HOLY ******* ***** ******** did a bee get past the air filter.

[vettemakesemwet]

Oh yeah, make sure there are no vacuum leaks. On stock LS/vortec engines, high fuel trims at idle and while driving, points towards un-metered air entering, the air measurement device has been changed, or electrical connections are not sufficient. If ALL of those are good, the problem is in the tune. Be careful with oiling the K&N. Contaminates MAF sensors like mad.

[2xLS1]

Smoke test the entire intake downstream of the MAF is the only way to find vacuum leaks. I just smoke tested a 5.3L a couple days ago with proper fuel pressure and +25 trims. Found every bottom injector O-ring leaking.

[MathGreek]

Finally, got around to testing some of the things mentioned. While in SD, fuel trims were significantly better generally staying under +5%. So I tried cleaning the MAF and swapping to a different MAF and nothing helped. Following some of the guides on here, I disabled LTFTs and adjusted the MAF calibration using average STFT% vs MAF frequency. I re-enabled LTFTs and they seem to be in the +/-5% range now. I notice there's still a lot of spikes in STFTs though. Looking at the log, should I try to adjust the MAF calibration more?