have you tried adjusting the fuel maps to compensate for the lean conditions? lets say your 5% lean maybe up the maps 5%

 

I did try tuning the maps to compensate but my fuel trims are wildly sporadic! It almost seems like there is a fuel delivery issue, intake leak, or exhaust leak skewing my numbers. My data logs look ridiculous and are so inconsistent. At operating temp, part of the map will go lean (-8% or so) while driving around a bunch. Then all of a sudden the same part of the map will start going extremely rich (+20% or so). My map table (volumetric efficiency table) is set up with RPM & intake manifold pressure.

I checked my fuel pressure before the fuel pump replacement and sometimes it would only get up to 10 PSI and then on the second key crank, it would jump to 58PSI. I don't know if there is a bad wire communicating with the fuel pump or if something else is involved. I'll test for the fuel pressure issue tonight or tomorrow to see if the fuel pressure issue persisted with the fuel pump (I imagine it is still happening).

I know the crank position sensor is involved with determining timing. Does it have any influence on fuel delivery?

 

New vital information that took you 3 months to post. You do the math!

 

I did mention the vital information back then! I just thought it was a faulty fuel pressure gauge set instead of an actual lack of fuel pressure! Remember? Same fuel pressure result again just before I swapped the new fuel pump in, which is what convinced me it was not due to a faulty pressure gauge.

I completely replaced the ignition housing and lock cylinder assembly along with cleaning all the connectors a few months ago.

Here's an updated summary:

Issue: Sporadic no-start on first "timed" crank mode (turn key and release). Almost always starts on second turn of key (immediately). Engine occasionally "stumbles" during initial crank. Back-firing during start-up issue is common. This issue existed with previous owner and entire time I have owned it.
Codes: P0136 & P0137 frequently until fuel pump replacement, P0138 & P0171 rarely
Fuel trims: generally very lean (~+20%) and jump around a lot (even during very long datalogs)

Replaced (yes, I have thrown wayyyy too much at this thing):
1. Replaced ignition lock housing (includes passlock module) & lock cylinder assembly (and cleaned connectors)
2. Properly secured faulty engine-to-battery ground
3. Cleaned all fuse blades (which had been subject to arching during the bad battery ground)
4. Replaced battery terminals (320,000 miles on OEM terminals with no issues).
5. Cleaned all engine component connectors and inspected for corrosion & lightly inspected wiring harnesses
6. Replaced plugs & plug boots (1 plug was seized and had a cracked insulator)
7. Cleaned MAF
8. Cleaned throttle body
9. Replaced MAF
10. Cleaned intake & injectors via tapping into fuel rail (w/high PEA cleaner)
11. Tested injectors (injectors good resistance & proper functioning)
12. Thoroughly cleaned intake ports by hand
13. Replaced injectors with higher output injectors ("late model LS" injectors)
14. Tuned for new injector flow rates
15. Replaced intake manifold & throttle body gaskets
16. Leak down test on fuel pressure gauge: dropped 5PSI quite rapidly (at varying rates, but much more the factory spec)
17. Tested for spark during "no-start" situations: spark is present during no-start
18. Tested for injector pulse during "no-start" situations: injector pulse is present during no-start
19. Smoke-tested intake side of engine with no leaks found
20. Inspected EVAP lines for cracks
21. Replaced fuel pump assembly (P0136 & P0137 have not returned in ~80 miles so far, but no-start issue persists)

 

I don't get 10psi when I turn the key on! 55-60psi starts right up within 3-4 revolutions. Go back to the ignition switch and check voltage on 1st crank.

 

I believe you! I would expect 58 PSI, and I have seen your pretty girl fire right up nicely.

Is this wire the one I should be checking?

 

Update on fuel pressure test:

Scenario 1: Fuel pressure occasionally will not build, and I assume the pump is not running during this time (new fuel pump is too quiet to hear when it is running).
-in this scenario, the engine will not start with 100% confidence
Scenario 2: Fuel pressure will quickly grow to 57 PSI and slowly drop after reaching pressure
-in this scenario, the engine starts with some subjective percentage (~65% confidence)

 

I don't see any mention of #66 on your grocery list? Did you check or swap with #72?

 

I did swap around some relays a couple months ago. I believe I included the fuel pump relay.

I just swapped the #66 for a clean relay and the issue persists.

 

Clean? Did you test it? Fuel pressure should go to 55-60psi on the gauge koeo. KOEO sends signal to ->bcm->pcm->relay->fpm.
You have a very rare situation, could be caused by aftermarket tampering?