I have stock Main Spark table and the PE Spark advance vs RPM is stock also.
I know many of you zeroed out this last table and added the additional spark to the Main Table.
Why I can’t see the additional spark when in PE?
Example: 100 TPS
Coolant 88 deg °°C
Commanded AFR 11.64
O2 volts 925
MAP 99,3 Kpa
RPM 3300
Spark adv 20.70 deg
Ref Spk Adv 14.72 deg --- (14.72 + distributor setting(5.98)) = 20.70
NO spark retard.
The main table says that at 3200 rpm the spark advance is 20.04
The table “PE Spark advance vs RPM “ says that at 3200 RPM in PE it adds 4.92 deg
Why I can’t see the additional spark when in PE?
(should I see about 25 deg..)
Thanks.
-Beppe-

 

No one knows where I loose the additional spark?

 

there are more tables involved in spark (at least in my 8746). There is a coolent compensation spark, the spark bias, etc.

The real test, would be to drop the PE spark by 1*, do the test again, try to get the temp, same conditions, and see if it commands, 14* or 13*.

 

If everything is working properly (including your scan tool) then you SHOULD see the additional spark added when in PE.

What are you using for a scan tool? How are you determining your don't have any knock retard? The main reason for a "discrepency" between Relative Spark (I ignore the Total Spark) is because is generally the ECM pulling spark out due to knock. It wouldn't be the first time I heard a scan tool wasn't displaying something properly.

As suggested by Dewey, try altering the spark value in the PE table a bit. Including setting the "Max Knock Retard in PE" to 0.

 

I'm using Datamaster, and I can determine that I haven't Knock retard because I haven't knock counts and no knock retard, and the total timing is the timing at the distributor (6*) + Ref Spk Adv.
I can determine also that I haven't knock retard because when I have knock retard the timing changes accordingly.
The coolant compensation spark, the spark bias can't be the culprit, because at this coolant temp I have a SA base temp correction bias at 20.04 deg at this load and temp I have also 20.04 deg so I can assume that I havent nothing to add or nothing to subtract from the timing (20.04 - 20.04 = 0 deg).
I will try to lower the "PE Spark advance vs RPM " table ...
-Beppe-

 

I Set the timing again and i can't see the ADDED spark in PE.
The end of the story is that im running total timing of 20/21 deg at WOT from 2000 rpm to 5000 rpm!
all readings on datamaster are
reference SA: 14deg
and Spark advace: 20 deg
or
reference SA: 15deg
and Spark advance: 21 deg
When I have 2 deg of retard i have
reference SA: 12deg
and Spark advance: 20 deg (a real 18 total deg advance, 12 +6)

I zeroed out the PE Spark advance vs RPM and added to the main SA table.
Now if I'm at 3200 at 100% TPS I added 5 deg to the main table (from 20 to 25).
Datamaster shows (as expected 19deg reference SA and 25 deg of Spark advance)
At 4800 rpm the PE Spark advance vs RPM was 7 deg.
So I added 7 deg to the main table (24 + 7= 31)

Datamaster shows (as expected 25deg reference SA and 31 deg of Spark advance).
So the car is able to handle the increased SA (sometimes I have some deg of knock retard...).
So I have to find WHY when the total timing is (main table + Pe Spark advance vs RPM ) I haven't the total spark advance requested.
Yes, I can retain the PE Spark advance vs RPM zeroed .. but in this way i'm not able to understand the logic used by the calibration.
Please help me to understand.
-Beppe-

 

The only thing I can think of is that the ECM is not going into PE mode. Check the commanded AFR, it to should change when in PE mode.

RBob.

 

I don't know... All seems indicate the ECM is going in PE mode.
BLM and INT goes to 128/128 steady.
commanded AFR averages from 10.90 to 12.50 at WOT
O2 mVolts goes from the tipical jumping situation of the closed loop to the 900/930 value in PE..
The only thing that do not follow the PE law is the timing, stuck at the value in tha main spark table.
Is thereSomething else to check?

-Beppe-

 

I try to post again..

 

From your testing I'd say datamaster is wrong again. Try different software, there are lots of freeware that all work with the same 2 transistor or max232 cables.
In the ANHT hack there are 2 "spark advance" parts of the ALDL datastream.
Datamaster might be looking at one and not the other. I don't have experience with a p4 test bench so I'll have to hope that somebody that has one can verify that these 2 locations are indeed different. I'm just guessing when I say that one of those 16-bit locations isn't displaying the final SA and that is what datamaster is displaying.
You could as an experiment, change the code in the chip at those locations by swapping the code.
Make it into the following;

 

Might try looking at your scanner software, and see if the RAM location it's using for the ALDL is actually the final spark calculation.