Lo Spark above 30% throttle

[limited cv8r]

2006 VE SS commodore,L98 6.0L Auto E38 ECM. Car is dropping to the Lo spark table approx above 30% throttle,really killing power,car is standard apart from a catback system. Fairly new to E38 so any advise,suggestions, where to look greatly appreciated.
Tunes and log attached.

[limited cv8r]

Are there any settings in the Knock or Torque control that may cause this?:help2:

[limited cv8r]

Ok,so after a bit of looking and reading I find out that the octane scaler reads opposite to the LS1 PCM's. So I now believe that I am not dropping to the low spark table but basically running on it all the time. I have also read that the PCM will set the octane scaler to 100% whenever a MAF or Knock Sensor DTC is set.
{B1932} Octane Scalar ESC DTC Default, value= 0.998,
Description:
If any knock sensor faults are active (P0325,P0326,P0327,P0332) the octane scalar is defaulted to this value.

{B1960} Burst Knock ESC DTC Default, value= 0.998
Description:
If any knock sensor faults are active (P0325,P0326,P0327,P0332) the burst knock memory cells are defaulted to this value.

I will have to get this car back and check for these codes,from looking at the tune,all codes should set a MILL which I believe the vehicle is not.

[CV8IIM6]

Something for all of us to look out for. Good job.:thumb_yello:

Keep us posted.

[GMPX]

I spoke to someone last week with an L76 that had the octane scaler at 0.998 too, thing is, it was there due to severe knock. The customer had always complained of bad fuel economy.
Of course they assumed it was a tuning issue that it was running so bad, but it was something was wrong with the car.

BTW, you need to pull power to the ECM to reset the octane scaler back to 0.
Do you think GM swapped the octane scaler around just to confuse all the calibrators going from GenIII to Gen-IV?

Cheers,
Ross

[limited cv8r]

Cheers, I'll see how I go. Also it looks as though the E40/LS2's use the same type of octane scaler, do we log these with Aspark or the OCTSCL_DMA pid

[GMPX]

I think both require the DMA PID as GM never implemented the octane scaler in the normal PID set (ah, why!!)

[limited cv8r]

Can I use the OCTSCL pid for E40/LS2 even though it is in the E38 pid list?

[limited cv8r]

Got car back today, disconnected battery,octane scaler reset to 0.000 .
First dyno run,straight back to 0.998. No logged DTC's. Owner taking car to holden to complain about S**T power.

[GMPX]

The car I was talking about was showing a constant 3 - 4 degrees of knock at anything more than 30% throttle. The ECM was only doing it's job.
You might want to write down for your customer what you found, it will help the techs at Holden get on the right path faster. Otherwise I can see the ECM being replaced as a solution.

[limited cv8r]

Yea, customer took notes, hi spark,lo spark,octane scaler, DTC's,maf sensor ,knock sensors, etc. No point sending a man in unarmed.
Explained that I could improve his power, but it would compromise the safety systems that the engine management uses.