5.3 - p0171 & p0174 Code

[89db]

Hey guys!

Hopefully, someone can send me along the right path!

I swapped a 5.3 LM7 (From a 2005 Tahoe) in a 51 Chevy Truck. Originally I had a misfire, which is fixed now, bad injector.

Then in emission, I couldn't "COMPLETE" the O2, Oxygen Sensor, but the Oxygen Sensor Heater would complete. Since the misfire is fixed I get Code p0171 & p0174 and the Oxygen Sensor get completed.

The engine is stock but I removed most of the emission codes, everything else is unchanged in the tuned. The truck doesn't have anything "stock", so I am using a Tahoe Cold Air Intake cut to length. Hooker Manifold with 2.5 inches exhaust and highflow cat converters.
And the EVAP is unplugged and non-existent.

I attached a log below (daily run with a few pulls).

I am new to this kind of tuning so if someone with experience enlightens me I would be grateful! Anything I can look for, or that I need to tweak?

Thanks!

Dailyandpull-nointerpolation.csvLean-dailyrun withpulls.hpl

[5FDP]

Well those are lean codes.

So have to checked for vacuum leaks or exhaust leaks pre-o2 sensor?

What is your fuel pressure?

You need to running 58psi.

[89db]

Vacuum leaks seems to be non-existent. I diagnosed that during the misfire issue.
Fuel Pressure is 58-60psi. New pump, new lines, new tank.

Exhaust leaks, seems to be under control but I will check again! It is a full custom exhaust so maybe there is a pinhole somewhere and I haven't heard it!

Anything else?

[jpierro79]

Ok either you have exhaust leak throwing your o2 off or your intake has incorrect tubing throwing your afr off. If the intake tubing is larger that oem it will read less air therefore less fuel. Gm vehicles are highly sensitive to intake changes. Also you said unplugged your evap. Like unplugged the actual plug or blocked the line cause the only way you can get those lean codes at the same time are
Low fuel pressure
Bad MAF SENSOr
Incorrect intake tubing
Leak between maf and intake manifold
Bad map sensor
Exhaust leak on both side
Or a vacuum leak
You said you unplugged the evap. Like how a connector ? Vacuum line? You realize if the evap purge valve is open it will draw vacuum from the gas tank and charcoal canister causing lean codes

[89db]

Could be the intake. It is a cheap "no-name" tube from eBay since it had to be custom, so maybe the diameter is off.
Anything in the log i should look at that could indicate that?

the EVAP purge valve is on the intake manifold but the harness is unplugged. It was plugged before but during the first startup I could hear it open and sucking open air (as I don't have the whole evap line), so I just unplugged it.

[jpierro79]

if your put your stock intake back on your frequency will change at idle and lets say your cruising at 2000 rpm it will be lower than stock intake. Best way to check is log your ltfts with your intake then log then with stock and see if there is a big difference. your ltft can compensate i think up to 20 percent. if its only at idle you have large ltft correction and not as much driving "say the higher the rpm the less correcion" its a vacuum leak.

[5FDP]

The MAF on those trucks motors is it's own housing, so you can/could the piping but the MAF itself is going to stay the same size.

[jpierro79]

if the piping is smaller or larger after its going to throw it off. youll create a vacuum in the tube and turbulance if its smaller so it does matter. if its larger after youll create turbulance and flow latency. why do you think every intake that works known to man using a maf has the same size tubing start to end???? airflow dynamics also includes bends transitions sizing changes why do you think some cylinder headers with smaller intake runner volumes can flow 30 percent more than others??why do you think the good companies take time to manufacture and test these products and the cheap chinese crap hits the shelves in a few days. I can't begin to list is just general repair the cars that have thrown this code just cause intake tubing.
honda civic 2.4 and 2.0 ive seen about 10 garbage intakes on these cause it
ford triton 4.6 5.4
gm every v8 with a maf
chevy cobalt with injens with tubing reducing throw a rich code instead
lexus is350 f sport guy made to big of piping stock airbox end gues what lean codes
chevy sonic 1.4 turbo injen intake
the list goes on and a lot of these like the lexus can use the stock end it doesnt matter your disrupt the readings

heres another thing people dont know. I cant understand why they dont figure out that with long tube headers at idle the fuel mixture collects where the 4 pipes meet throwing off upstream o2 i mean its damn near a 4 inch square reducing down to 3 or 2.5 inch pipe. the air doesnt move over the 1st o2 correctly. yet these companies insist on putting the o2 at the merger the factory tuning no matter how much you offset the o2 tries to pull fuel. Mine tries to pull 5 percent i have to have it 5 percent rich at idle even if max the transition to 900mv which is like going 12.5-1 it will still pull fuel at idle all the way to 15.8 idle like crap and lope like cam without one. Ive seen aaron kaufman on gas monkey garage made that mistake of making a custom intake tubing on a car with a maf and it wouldnt run worth a crap. he supposed to be the bearded wonder. we all try things but if you automatically disclose that now youve changed something and now you have a problem that your not the cause of it youll never get anywhere. Ive made thousands of mistakes over the years im sure of it.

So here we go if the theory holds true that the tubing from maf to motor size shouldnt matter as long as the maf stays in its original tube. I want the next person to reduce it down to 1inch between the oem maf tubing connector and the motor drive it and show me after 10 miles of driving that it works