Finally rebuilt and running! P0068 fault only on boost - Tune and log inside

[megadeus]

Hi guys, I've been lurking on the forum since I first asked for help and I found several mechanical issues.
There were the wrong valve springs which caused a broken intake valve.

The kids and I rebuilt the engine, installed new rings with boost friendly end gaps. I also rebuilt the 4l80e because the internal condition was unknown to me. (I'm an automatic transmission guy by trade)
I found the pump bushing actually eroding pretty badly from poor engine grounding when cranking. I have installed new grounds straps since then.

My real job right now is teaching auto shop to high school and community college kids. I've been working on this truck at the school to share the trials and tribulations of hot rodding in the modern era.

Bio on truck:
2006 Silverado 1500 4.8 - 2003 PCM/TAC modules
4l80e Transmission - 1996 era
3500 RPM stall torque converter
On3 76mm turbo bolt on kit.
EFIlive COS3 semi-open loop speed density
Cam is unknown of origin . - has .595 lift on intake and exhaust (my presumption before i took the engine apart was that it was a 4.8 OEM cam)
LS1 '241' series heads now installed with PAC1518 valve springs.
PCV catch can vented to atsmosphere (for now)

Tune and most recent log.
LS1B 2006ChevTurboAutotuneV1a_0007.ctz
Log_0085.efi

My current issue is the P0068 rearing its head on boost. I am trying to get this ready for a trip to a dyno shop for a power run that will also be a field trip for my students. I will do my best to give feedback from every suggestion given here.

She idles well except for a being a bit rich while warming up. Am I asking too much for the engine to idle below 900 rpm too early on warm up? I'll post a log of the warmup cycle later on.

Thanks,
Jason

[megadeus]

I have been looking at other publicly posted COS3 tunes for a bit of research.

Tomorrow's trial by fire:

1st - I think I need to punch my C6101 & C6102 tables up a bunch and then come down gently 10% a time to find my safety net for the ETC.
2nd - I will set B3618 to 1.25 for a bit more safety
3rd - I will set B3616 to 65% TPS below 3200 rpm 35% TPS above 3200 rpm. *My tune is currently at 90% across the B3616 map.

I'm writing this down so I'll remember what I'm thinking about. So I don't end up throwing out a wad of paper I might write these notes down on accidentally.

[joecar]

Hi megadeus,

Good job on the 4L80E rebuild (pump bushing pathing to ground).

Also in your tune file, A0012 and A0013 are quietly indicating they are out of range... set them to max-1, save file, exit tunetool, restart tunetool, set them to max (this is a trick which I will explain later).

[megadeus]

JC,

I performed the A0012 and A0013 adjust and resave procedure as you recommended.

I upped C6101 and C6102 by 100% and now have BOOST! All I have to say is Gig-GAH-DEE!

I'll post logs after I put in some road time and adjust the base VE tables more.

[joecar]

Good job

[megadeus]

Here is my new updated tune and some longer logs. I'm gonna have to do something about my Trans fluid cooling. My Trans oil cooler is undersized but it was all I had sitting on the shelf here at the pit o' poorsville. Any recommendations?

LS1B 2006ChevTurboAutotuneV1a_0010.ctz
Log_0093.efi
Log_0092.efi

The last log was after I put in $20 of fresh E10 Pump gas.

I haven't been brave enough to put the go pedal down all the way yet.... I know my parts can handle it but I need good gas in the tank first. The old gas has been in there since May! The horror!

[joecar]

Try the B&M 70264 (it comes with everything you need to install it), so the cost is not so bad.

Yes, change to new gas, and don't run the engine at load just yet...

look at this first:
B3618 PE is set 0.7998 EQR (instead of 0.7998 lambda) which is way too lean (and you already know that EQR = 1/Lambda and vice-versa)...
in tunetool, go Edit->Properties and set Fuel units to EQR, restart tunetool and redo B3618 (see below).

( for commanded fuel we'll use EQR, for wideband measurement we'll use Lambda, this helps to avoid confusion )

Since you're going to run boost, try doing this:
- set B3647 to start ramping fuel up from the 75 kPa column so that it reaches EQR 1.18 at the 100 kPa column;
- set B3613 to 105 kPa,
- set B3618 to EQR 1.25 all across,
this allows non-boost fueling to come from B3647 and boost fueling to come from B3618 (this gives you more control over fueling).

Also:
- B3618 is good like your have it, maybe reduce the 65% down to 55% or 50%;
- set B3609 to 0.05 sec, all cells;
- if you have removed the catalysts, then disable B0701;
- if you have removed the EVAP system, then set B0501 to max (just in case you ever enabled closed loop);
- B5913 has too much timing (where it has a swath of 27 degrees), for boost you want to reduce timing below that of NA timing.
- B5914 should be lower (maybe 10 degrees) than B5913... note that with a COS the HO/LO adaptive spark still functions in the presence of a MAF DTC.
- set B1901 to 640 ftlb.
- C6101 and C6101 you already took care of (you may need to go up more in the 5000-6500 rpm columns).

[megadeus]

Missed that FUBAR on B3618 big time!

I have made those adjustments as suggested. There are no runtime logs as it's the weekend and the truck is locked up at the school.

Take a look at B3647 table please. Is is wise to do it the way I did on the assumption that below 2000 rpm I will not be expecting PE?
The engine does dabble in those cells 800-1600 going from idle to tip-in with that loose converter.

LS1B 2006ChevTurboAutotuneV1a_0011.ctz

[joecar]

Yeah, don't be in a hurry, measure twice (or more) before you cut.


You could be idling at the red signal, and then on green mash the throttle, rpm will still have to travel up thru 400 to 2000 even if the converter has a loose stall, right...?

Even with a loose stall there is some amount of load on the engine (it has to push the the converter turbine around, but the stall looseness is not yet allowing it to couple so it generates heat, this heat is the conversion of energy from the engine into heat, so the engine is still working hard, just not quite as hard as with a tighter stall)...

So you would need fuel from B3647 right away...

I would carry those columns all the way down to zero rpm.


Then of course, you would analyze this while doing some street driving (stop light to stop light), make some adjustments, compare/analyze using seat dyno (seat of pants).