ECU Pulling 5 degrees? no clue why?

[my1path]

Its most obvious on the far right, the hidden cells in coulmn 80 are 25 degrees so even with cell averaging I should not trace as low as 23.
Under light loads below 3k rpm it seems like a roll of the dice, sometimes it follows the map and sometimes it pulls timing.
No knock cells are on the map and the problem persitsts even with Knock Sensor un-marked under DTC 3.
What am I missing?

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[Matt]

Timing can be pulled without knock cells off.

Unticking the DTC just prevents the fault code displaying (if there is a fault code) but does not prevent timing being pulled. Do you have a knock fault?

[my1path]

I have not received any codes for knocking with the knock DTC marked.
The KS is in the valley under the manifold. I guess I should have built a sub-harness so I could unplug it for diagnostic.

I did try a conservative nearly flat map with no cruise advance and it still pulled timing...

[my1path]

If I run a log is there a particular thing I should look for?
I'll follow timing vs TP and RPM and see if I find a connection.

[Matt]

I'm not sure what else would retard your timing with this particular ECU, apart from knock. I'm not sure what other information I can provide. You can try clearing your knock retard maps to 0 to see if that helps

[my1path]

I highlighted my whole main timing map and subtracted 5 today. No change in its behavior.
But I looked more closely at the trace and today it looks like its only happening over 3k RPM.
I will try setting all knock maps to zero. There seem to be several that read in different ways. not sure how they all interact with each other.

[RomChip200]

Check these tables (sorry they are for Z32, look into ADR Fiels for correspondence with your table addresses):

#Timing
TIMING_ADVANCE,&H7EC0,16,1,16,1
TIMING_RPM_SUBTRACT,&H7540,16,1,16,1

They are after start time advance according to temp and retard according to rpm. If wrongly balanced, they can push or pull timing.
Always active on Z32.
Btw, is your timing following these tables when warming up (20°C-50°C range), it should push timing at low rpm.

These ones pull timing in given ranges during warm-up (b/w 30 and 55°C):
WARMUP_TIMING,&H7F60,16,1,16,1
WARMUP_TIMING_TP_MAX,&H7FD6,1,1,1,1
WARMUP_TIMING_RPM_MAX,&H7FD7,1,1,1,50
WARMUP_TIMING_TEMP_MIN,&H7FD4,1,1,1,1
WARMUP_TIMING_TEMP_MAX,&H7FD5,1,1,1,1


IGNITION_RETARD_TEMP,&H7B90,16,1,16,1

This will retard timing according to temp in case of knock.

No other idea for the moment.

[Matt]

Warmup timing and timing advance/retard are defined in the M30 address files, so they can be adjusted

Different addresses to Z32 though:

BAA2 : B6 15 8E ldaa RAM_158E_RPM_MSBDiv2
BAA5 : CE F5 B0 ldx #ROM_F5B0_Timing_RETARD_vs_RPM
BAA8 : BD 80 9F jsr JSR_809F_Interpolatex16
BAAB : 36 psha
BAAC : 96 B1 ldaa RAM_00B1_CoolantTempIdx
BAAE : CE FE C0 ldx #TIMING_ADVANCE_vs_Temp
BAB1 : BD 80 9F jsr JSR_809F_Interpolatex16

[my1path]

I've seen some of those in the .adr but I'm not sure where I'm going with them.

Timing is being pulled when engine fully warmed up.

I did see that the M30 adr references the BASE_RB20_VG30_256_E.adr (so that's where some new maps came from after an update) has a parameter there changed ?

[my1path]

I found an older adr from a backup and did a side by side.
Left is old march 2015? Right is dated 9/2/2019

old v new adr.jpg

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when I can get back to the car I might try reverting to see if it helps (or if I've always had this problem, I didn't mess with timing when I was running the stock MAF)

[Matt]

Those are pretty much the same, only the timing advance beta was moved with the knock parameters (and some extra parameters added in that area)

Winmerge is what I use for comparing files

[my1path]

So what's my next step? Finding a way to disconnect my Knock sensor? Zero all the knock settings and take a log?

[Matt]

Post tune and log file so I can check it here. I don't have any M30 ECUs to check on however

[my1path]

Post tune and log file so I can check it here. I don't have any M30 ECUs to check on however

I have a damaged one I can send you. I think it got a little corrosion inside it. Started keeping #1 injector open. If that interferes with bench testing I could probably buy a good working one to send you.

[Matt]

Might be okay, customer returning one this week for checking