2-Bar Woes

[onfire]

Did it run well after the dyno tune or did it always buck at wot?

[NAH]

No, the original dyno run was with a 1-bar sensor fitted.

Something is pulling timing when loading the engine. The High Octane fuel table shows a timing of 20° for a given rpm/cylinder-grams/air. The actual timing recorded using scan tool is 4°. What would cause this?

[ringram]

Some cells in your tune have the low octane table reading higher than the high octane.
(eg) 3200rpm at 0.64g shows 22* in low and 18* in high.
Without knowing the exact algorythm that the PCM uses to calc final spark Id suggest that sanity checking the entire tune would be a good start. Weird stuff like that might throw a spanner in the works.

As suggested starting from a known good stock tune and following the guides and tutorials on here and in the docs is always recommended.

[NAH]

Some cells in your tune have the low octane table reading higher than the high octane.
(eg) 3200rpm at 0.64g shows 22* in low and 18* in high.
Without knowing the exact algorythm that the PCM uses to calc final spark Id suggest that sanity checking the entire tune would be a good start. Weird stuff like that might throw a spanner in the works.

As suggested starting from a known good stock tune and following the guides and tutorials on here and in the docs is always recommended.

I have constructed a tune based upon the stock 2004 Monaro tune from Holden Crazy but using the custom OS *03. The values are very different in places & I'd like to know more about what the calibrations do. The whole ETC area is very 'grey' as mine has a cable throttle. For some ETC calibrations, the folder in the list is RED & I assume that these are not relevant to my PCM.

Anyhow, what I am attempting to do is co convert the current tune (which has been constructed using the 2001 Commodore Custom OS *03) to the one mentioned earleir as you suggested. Then I can compare the differences between the the stock 04 Monaro tune & the current tune. I will have made the changes to the stock tune as described in the custom OS tutorial.

BTW, sorry to not have called you today but had some serious s**t with an ongoing site - work gets in the way of everything.

[ringram]

Do you want to convert the old tune? Depends on what you are trying to do.
You can convert it to see if the OS level helps. But you might want to stage the migration so you can observe what happens as you bring over each table.

[NAH]

Success, the problem was with B6216 Burst Knock Retard. Setting this to zero cured the problem of the pulled timing. Now I am seeing 140+kpa manifold presure but the AFR (indicated by the sensor voltages) a bit rich.

I need to tidy up the tune for the boosted region A0009 & the AFR settings, but need some dyno time to make it right. I will also fit (hopefully) a wideband next week.

I am a happly chap. Thanks Richard for your invaluable help, top job.

[dc_justin]

Success, the problem was with B6216 Burst Knock Retard. Setting this to zero cured the problem of the pulled timing. Now I am seeing 140+kpa manifold presure but the AFR (indicated by the sensor voltages) a bit rich.

I need to tidy up the tune for the boosted region A0009 & the AFR settings, but need some dyno time to make it right. I will also fit (hopefully) a wideband next week.

I am a happly chap. Thanks Richard for your invaluable help, top job.

Ah, I had that problem when tuning. It means that the column to the right of the highest column you're seeing in the boost VE table is too high. Look for that "shelf" in the boost table and reduce it manually to something reasonable.

Example. You may see 179kPa at WOT. Scanner will log that data in the 175 column, and your AutoVE stuff will only alter that 175 column. In actuality, it's interpolating between the 175 and 185 columns. If your 185 column is drastically larger, BKR will be triggered.

[ringram]

Actually it was being triggered at quite low map, even in the stock OS.
Adding the new 2bar sensor obviously put bigger numbers into the equation making it worse, but it was there in the stock OS too.
All sorted now, most people zero out BKR anyway. As long as the spark map is done properly it shouldnt be needed. We logged no KR under load and only a small one or two degree tick on taking off from idle.
I think its for designed for granny who refuses to shift down from 6th gear to overtake around town.

[dc_justin]

Actually it was being triggered at quite low map, even in the stock OS.
Adding the new 2bar sensor obviously put bigger numbers into the equation making it worse, but it was there in the stock OS too.
All sorted now, most people zero out BKR anyway. As long as the spark map is done properly it shouldnt be needed. We logged no KR under load and only a small one or two degree tick on taking off from idle.
I think its for designed for granny who refuses to shift down from 6th gear to overtake around town.

If I zero out BKR, I get real knock BAD when rapidly going from light throttle to heavy throttle. Roots supercharger will go from 10" of vacuum to full boost almost instantly, so BKR is a lifesaver there.

[ringram]

Cool, NAH can keep an eye on it and maybe put a little bit back in if required. It was set to 14* before zeroed. I guess the delta airflow values could also be increased to move the trigger level up too.
Lots of fun to be had tweaking