I don't remember if we talked about it before, but what are your fuel trims as you cold start?

 

Long term -3.9 on Jan 7th. Not super knowledgeable on fuel trims/ maf adjustments but it hasn't caught my eye with any extreme values

 

Downloaded file. I've been having some really interesting things happening during my cold starts, just looking to see if there are similarities.

 

yeah go for it! If you want more I can post some others when I get home

 

Preliminary look, your STFT is doing some wacky **** starting at 1:56 in that log. On your next cold start try this:
1) Unplug your evap electrical connection (to the right of the engine)
2) Hop in the car, turn it on, but not over, just to get the OBDII to read on VCM Scanner
3) Clear CEL (even if there is none, this is just a reset).
4) Turn the engine over. You may need to be ready to feather the gas pedal.

What this does is 0 out the LTFT and goes by what is commanded. This may not entirely fix the problem, but it should at least give some clues if it's part of the problem. I'm currently editing a screen record I did of my cold start, and mine is significantly worse
As soon as I turn it over, my foot is pressing the gas a bit and I try to keep it around 1200-1250 until the AFR/STFT jumps.

EDIT: Link to my video

 

I’ll give it a shot! Ty

 

Playing around with it now:
plugged in my scanner and there was a C0895.
went away on startup.
hmmm

unplugged my maf sensor. Attempted to start car, fires, flares up stalls immediately. Much quicker than what my problem is but it sounds pretty similar.
Fired it up a few more times, no codes and seems like I have no throttle response (which is again similar when my stalls happen quick)

now
another thing noted, after a 600km round trip this weekend running like a champ, my O2 readiness is still not complete… but the O2 shouldn’t matter on cold starts anyway even if there is a problem there…

unplugged evap purge solenoid, cleared LTFT and fired it up, little bit of surging which is similar to my problem. But for the most part seems like a strong idle. Will leave it like this and start it up again tomorrow morning cold.
C0895 came and went again after.

C0895
Device Voltage Threshold
PSCM hmmmmmmm

Sounds silly but guess I should disconnect PSCM try starting it lol idfk at this point, I`ll just start praying for a hard fault..

 

One at a time, since you'll trigger a CEL for unplugging the evap. I would take a log on the next cold start.

 

Started, sounded like it wanted to stall a little but caught itself. Only evap purge solenoid unplugged

 

It almost looks like you're having the same issues as I am.
1) Cold start, once the idle figures itself out, everything is in operating order, including the STFT and LTFT (although mine stays fairly wacky)
2) The first few minutes of driving seems also ok, then once you start going it's still fine, but that first time idling after highway speeds, the STFT starts going all over the place, eventually messing with the LTFT
3) The AFR would eventually start going down to rich (12-13 instead of around 14.7) on idle to start compensating for the lean %s I was getting, so keep an eye on that as well (mostly throttle response from stop to first gear)

As for the EVAP, I swapped out mine as there wasn't a perfect seal on the plunger, which helped some, and I had a crack in the vacuum reservoir (small boost leak) so I did a bypass on that (I can take a picture later if needed for this).

When I finished doing my clutch line replacement, my car wouldn't start or even turn over. When I took it to the dealer, they told me my underhood fuse box was the issue - they had to use a lot of dielectric grease to make connections so the relays would function properly. I still need to swap it out (weather and all) and hoping this would resolve my issue.

 

bad evap purge solenoid would introduce rich condition if stuck open and no leaks (flooded canister). If gross EVAP leak, would run lean directly to the port at the TB

 

I’ve tested the purge solenoid and I can’t pass air through it when disconnected.
All my evap codes are off however, was thinking of turning them all back on see if the computer can detect a large leak/flooded at the canister

I would like to delete my evap system though. I think the pros of reducing the complexity of the system greatly outweighs the downside of losing a tiny bit of gas fumes for efficiency .

 

delete purge, not vent. vent will make filling the tank a pita

 

This isn't the same as the vacuum bypass right?

 

That's for an LNF. Or more for lnf

How would you suggest doing that JapEatr?

Plug TB port, remove purge solenoid, remove evap line going to purge solenoid and call it a day?

 

Just triple checked purge solenoid is good.

I’ll cap the throttle body when I get home to be 1000% sure and I’ll leave it like that and in time that should rule out an evap leak.

 

thats LNF only, and I dont think the Supercharger bypass solenoid would give you the same issues you are having.

 

 

Well I think your on the right track ProfDNS about it being fuel/ trims.
I found a log with my wideband in use and when I stall it get progressively more lean until it hits 18, holds it and stalls out.
Injector pulse, commanded AFR, its all there asking for fuel..

I regret returning the ECU I had here.
Can anyone identify what modules corelate to
0x543
0x544
0x54A
0x7E8
0x7EA
ive asked hptuners if they can identify them

 

It’s gotta be a bad ground though.
Bad module should be more consistent.

I’m gonna cut G105 off this weekend should be nice out, I’ll rewire it a few Inches back with a new terminal.

 

are you sure you have the correct injector data in the tune? or FP?

 

Fuel pressure tested fine, 50psi key on after sitting overnight, 60psi running.
I don't see how I could have the wrong injector data. The tune has worked for 2-3 years with only slight changes to WOT timing, MAF and taking out fuel above 3spi for Methanol.

 

flow / press hasn't changed in years I just checked

 

Got a little off point today.
Rewired all the power taps at the BCM, tightened bolts that hold BCM in and rewired all grounds near the BCM.
Hardwired my aftermarket radio and got rid of all butt connectors in that area.
*found an exposed wire between the radio and aftermarket gateway module*
-Kinda want to wire up my hands free controls while I have it all apart.

moving towards the drivers side now though, gonna clean up Methanol controller, Wideband and Interceptor gauge get rid of all my rats nests.

then tomorrow might be g105 day, remove my intake and try to get as much room as possible. Knees are starting to get cold and stiff haha

 

Really happy with today. Been wanting to redo my radio wiring for a long time.. took a lot of junk out.

and with a lot more room was able to get a good look at the dlc connector and I may have found my smoking gun. An exposed Tan wire! Gonna be hard to repair, 20 more min of sunlight let’s go!