Dreaded knock.... cant seem to get my tune right

[Dopey]

So what happens if the maf isnt installed? Sorry, left that part out as well

Thanks for the screenies, I'll increase the recovery rates similar to yours to see if it gives the dreaded saw tooth pattern or just spikes here and there (hopefully indicating background noise or a false positive)

[WeathermanShawn]

Mmm..thats kinda a 'trick' question..

Seems like from a previous thread, that you still are not going to run SD as long as you have not failed it in the software.

Now, how it is calculating CYLAIR..no MAF Frequency..Thats an excellent question.

I like Joecar's suggestion. Zero out your MAF Table and see what happens. Sounds like it still pulls out a MAF airflow if that Table is active...

Great question..

Edit: I agree, a lot of your 'KR' looks mechanical. One big spike..then nothing. I think I saw a couple of lower RPM 100% TPS that looked more real (sawtooth). The KR on my screenshot was real..I good hear some pinging when I lugged it on a hot day going up an incline. So, that gives you a pretty good idea of what 'real' KR look like on a scan..with a very fast Recovery Rate..

[joecar]

wow you guys are quick

@joecar I will try that, I would absolutely love it if it was that simple *fingers crossed* Injectors are stock (28.8lbs I believe)

@WeathermanShawn I am wanting to run completely no maf (OLSD)

When you zero the MAF table:
- if engine runs, then PCM was using VE table all along;
- if engine does not run, then PCM was using MAF all along;

So what happens if the maf isnt installed? Sorry, left that part out as well

Thanks for the screenies, I'll increase the recovery rates similar to yours to see if it gives the dreaded saw tooth pattern or just spikes here and there (hopefully indicating background noise or a false positive)

If MAF is not installed, this is what happens:
- PCM detects MAF failure and sets one of the MAF DTC's (P0101, P0102, or P0103);
- the presence of any of those 3 DTC's causes the PCM to ignore the MAF table and run exclusively from the VE table.

i.e. you are not in SD mode unless a MAF DTC is current.

You can also get the MAF to fail by editing the failure thresholds (e.g. setting C2901 to 1 Hz will fail the MAF).

[joecar]

The key is: when a MAF DTC is current, the PCM is ignoring the MAF and running solely from the VE table (i.e. SD).

Then if you disable long term trims, short term trims, closed loop, semi-open/closed loop, then you have OL.

Running both gives OLSD... when VE table is corrected, runs good like this (instant throttle response), but will most likely damage cats in long term usage (so replace with pipes)...

If you want to run cats, first correct VE (in OLSD) and/or MAF (in OLMAF) or both, and then run either CLSD or CLMAF... you want the front O2's to switch to allow the cats to function correctly (which prolongs their life)... the rear O2's will monitor the cat function/efficiency.

[joecar]

More info, see my profile, scroll down to where it says this:

PCM calculates airmass from:
- above B0120: MAF,
- below B0120: MAF (steady throttle/airflow) and/or VE (transient throttle/airflow),
- in SD (MAF-less): VE.

[Dopey]

Sorry for the late reply guys, I tried what joecar suggested and zeroed the MAF tables out and the car started up and ran fine...... So it looks like the person that did the tune before just had a different way of putting it into OLSD....

Just as a precaution I changed the tune and followed the AutoVE steps to put it into SD mode, but I still cant figure out what the knock is... Unfortunately its pooring today so I am not to keen to go out logging.... I will keep playing with the tune over the weekend and post up the results.

One thing I thought about was setting the timing table to 11 across the board (every cell) and seeing if I still get knock... Surely 11 is more than conservative...

Does anyone want to share a pic of their High octane spark map as a comparison? Im trying to figure out if my timing is just too aggressive?

[Dopey]

Another thought, how are people getting figures for B6240 - B6251? After looking through a few stock HSV (australian) tunes they seem to vary from one to the next...

[WeathermanShawn]

Another thought, how are people getting figures for B6240 - B6251? After looking through a few stock HSV (australian) tunes they seem to vary from one to the next...

Dopey, those are the ones I do not mess with..keep them stock. Perhaps you are asking which one is actually stock? Again, I leave those alone.

Here is my High and Low Octane Spark. Rarely get KR..only on very hot days..lugging engine etc. Thats on a 11.0:1 CR..91 Octane (Colorado-Western U.S. Highest Octane Gas).

Good idea to set 11 degrees across the board. That should help.

[joecar]

Dopey, are you getting any MAF DTC's at all (i.e. any of P0101, P0102, P0103)...?