Billiumss

iTrader: (11)

I just finished up a SD tune on a 1999 Camaro SS A4 with a 383. Awesome car, big 244 cam AFR heads, FAST 90 Intake, Nick Williams 90 TB, True Duals 3500 stall, VERY LOUD....

I got the SD tune dialed in nice and I switched it back over to use the MAF in closed loop mode.

The car runs great with the MAF, drives great, no stalling or surging. Ltrims are slightly negative when cruising and always lock at 0 when at WOT. My A/F is close (12.3) but hard to get right on the open street so I'll finish it up this weekend on a dyno.

The problem I have is that it's stuck in the Low Octane Table. I have the upper part of the high octane table set to 26 but I am only getting 21 at WOT.

What would cause this? I pulled the PCM fuses twice and that didn't help.

Does the PCM think it's in "safe mode" or something?

Bill

SmokingWS6

iTrader: (1)

copy and paste the high octane over to the low and see if that solves the problem. Most operating systems revert to low octane when in SD mode.

Billiumss

iTrader: (11)

I will have to try copying the high octane table and pasting it over....

That's the thing, I'm not in SD mode anymore, I'm using the MAF in closed loop mode.

foff667

iTrader: (2)

and your sure its not an adder table skewing the #'s?

Billiumss

iTrader: (11)

Not 100% sure but it "follows" the low octane table when you go WOT.

TAQuickness

iTrader: (28)

did you double check the maf settings (fail frequency, and fail limits) to make sure the maf is enabled?

Edit: also, if you look at the document in my sig, it's got a list of all the things to get into SD. I would double check all of them just to make sure...

Billiumss

iTrader: (11)

I used your document before, very nice write up, even works great for HP Tuners Off the top of my head, there is only one fail freq for the MAF in HP Tuners.

All MAF settings are back to stock settings. I have VER 2.0 and I used the compare feature to make sure. I can read the MAF freq and lbs/min with no problems.

Holden LS1 Tonner

What is you're knock learn factor reading when you scan ?

Billiumss

iTrader: (11)

Should be stock since I never changed it.

rgvsierra

iTrader: (7)

but wont the knock learn factor change as knock occurs, check to see if you have a 1.00 in the scanner.

TAQuickness

iTrader: (28)

for ***** and giggles, have you tried copying the low octane table to the high octane table (opposite of SD tuning procedure)?

You stated the timing tends to follow the low table. by doing this you could see if the PCM is interpolating the values between the high and low table or if it's stuck on the low table.

My understanding is the PCM will constantly interpolate a value between the high and low table unless both tables are the same, or a condition causes the pcm to only use the low octane table.

jimmyblue

iTrader: (11)

Log the Knock Learn Factor to see which table you
are closer to. If you see 1.000 then it's using the
HO table entirely, and any timing shortfall is coming
from spark adders / multipliers (IAT, ECT, et al).
You might also log the various available retard and
advance PIDs one time, just to see who's active.
Like Burst Knock could be seen on a car that has
a high VE slope with RPM, because the delta CylAir
threshold is met just by running RPM up quick, etc.
Log 'em all and then prune off the boring ones.

Taking one last pass through the codes and the
fail settings is a good idea, in case there's some
"fail safe" action going on based on the SD tune
disable-the-MAF stuff that didn't get reamed out
when all done. Don't know if that would be shown
by the KLF or not.

Billiumss

iTrader: (11)

Well, I ended up copying the high octane to the low octane and that works fine. The owner of the car came over to get it and we went out driving. I'm not getting any knock at all and I have his A/F at 12.9.

Even though both timing tables are the same, it will still pull timing, if knock occurs? At least it should since I didn't adjust for how much it pulls, right now it's set to 4 degrees to be pulled.

I'm still going to play around with it to find out why this weekend.

Holden LS1 Tonner

From what i know it will still pull timing but the next time it goes through that load / rpm point it will knock again with the pcm not having a low spark table to work with .

Looks like an awsome car , wish GM had sold the F-bodies here in Australia

WS6FirebirdTA00

iTrader: (33)

yeah itll pull out knock. just makesure the max knock settings are sufficent so it will pull a decent bit of timing out if need be

Steel Chicken

iTrader: (3)

+1 yep