88305tpiT/A

iTrader: (2)

So I have been noticing some strange things on my logs lately. First one is that during warmup, the computer will go from a BLM of 128 to 118 at about 90 degrees F. This is well below the min temp for closed loop but none the less there it is and it seems to force my engine a little lean for my taste, not to mention I have no idea what is causing it.

Second thing I notice is that when the computer is following the table: Spark Correction, LV8 vs. Coolant Temperature, something strange happens.
When I start below ~40F it adds about 9 degrees to base then takes it out per the table till it reaches the base value. This seems correct.
The only problem is the base value it seems to be using from the main SA table is 20 degrees, but in the main SA table it is 25. When the coolant temp reaches 112F and the computer enables the INT to move, the SA suddenly jumps to the correct base SA number in the main table, 25....

I do have the distributor base timing changed in the code to 14 degrees advanced instead of 6 but the distributor is set to 14 degrees to match - could this be the cause of the SA weirdness?

Thanks for any help.

88305tpiT/A

iTrader: (2)

Ok I found a thread right below mine on a similar topic (sorry) and RBob references a spark bias table.

I found two tables relating to this. It seems that one table : Coolant Temp Spark Correction Bias - is what the base timing is during warm up. oddly enough it seems to be the old value of the main SA table that ARAP starts with. I think maybe if I set this value to MY current idle range Main SA table value it would be right?

Does this sound familiar?

The other table I noticed was : Coolant temp Spark Correction Disable Temp - and this one is set to 112. so this is obviously the "snap" change I see where it goes from the correction temp to the main sa table, right?

ULTM8Z

You need to check your Closed Throttle Spark Timing. There's a table that's separate from the main SA table which drives the idle spark timing. Even though you may be calling out 25° in the main table, if the ECM sees 20° in the CTST table, it'll use 20°.

88305tpiT/A

iTrader: (2)

Ive never seen that table in the 6E code -- are you saying that cause its in the 8D code?

I did try to change the bias term I quoted above and it went the wrong way. I remember a grumpy post about how the bias term is subtracted to get the final SA term. So I will try again.

ULTM8Z

oops... sorry. I didn't know you were running 6E. It's in the 8D, I know. Not sure if its in the 6E.

88305tpiT/A

iTrader: (2)

I just checked the coolant correction table and it is linked to that bias term. Long story short I needed to correct both tables.

I will report back tommorow.

88305tpiT/A

iTrader: (2)

Nope, That didnt work either.

I changed the bias to 25 and redid the whole table so it looked like the table before I changed the bias and the car still warms up to 20 degrees...

What the heck is going on here, I am certainly missing something.

mike1986fyrbird

Look at my 730' spark thread a few posts down.

Z69 figured out that on the 730' ecm it uses the 100kpa column for the coolant spark table as a base for the changes to be made to until you reach the Coolant temp Spark Correction Disable Temp.

It is quite possible that the MAF system is the same - uses the 208LV8 Main Spark Advance column as a base reference for the coolant spark modifier until it reaches the desired tempature.

Try it out.

88305tpiT/A

iTrader: (2)

Ok cool. Thanks for the pointer to the other thread!

Link ->https://www.thirdgen.org/forums/diy-...k-advance.html