Attached is my current .bin for my turbo 3.8 with DIS. Bear in mind I have done considerable tuning of the spark table so the numbers will not add up exactly to what I started with! This is basically a copy of an e-mail to another member so here goes:
When I plugged the 1227749 / Code$59 ECM into my Buick engine, it would start fine, then it would get an "old tractor" sound, and "chutter along" weakly for about 3 seconds..... and stall. The timing was so far retarded the engine could not run. By disconnecting the EST Bypass wire, the engine would run OK but would not have any spark advance.
The distributor HEI module gives a reference signal when the trigger points in the pickup coil are in alignment. This is very close to TDC. The ECM returns a pulse to the HEI module when it is ready for the module to spark.
Electrically, the DIS is the same. Just like the HEI module, it gives a reference pulse and waits for a return pulse before firing the spark plug. BUT the DIS sends its reference pulse about 33 degrees LATER than the distributor!
By converting from distributor to DIS, I effectively "retarded" the reference signal by 33°. To counteract this effect, the ECM's programmed timing had to be advanced by 33° across the board.
This is what I determined through tuning with real-time, and if there are any errors, or an easier way to do it, please feel free to correct me. The attached BIN does run very well though, so it can't be too far off!
The member I was talking to us setting up a different DIS system which has a 60° retarded reference angle, so the numbers are based on 60° here:
The following values will ADVANCE the timing when they are REDUCED. Set them to 0:
Spark Reference Angle [was 0] is already 0
Coolant Advance Bias [was 20.04] (this advances it 20.04)
Boost Advance Bias [was 21.80] (this brings it up to 41.84 - but still not 60 yet)
We're out of "bias" settings, and still need to add 18.16° of advance!
Open the Coolant Advance Correction table (F2). RAISING these values will ADVANCE the timing. Select (highlight) ALL cells in the table. Open table editor and select the Offset +- function. Put 18.16 in the editor and hit "execute." This raised all values by 18.16° across the board! Add this to the 41.84 gained by reducing the bias values, and you have 60°!!!
Now that the "60° of retard" has been corrected you have to give the ECM "head room" to operate without hitting the limit. Do this by raising the Max Spark Advance relative to Reference:
Max Spark [was 46.76] (ADD 60) results in 106.76° for your engine.
So far this is what's been done:
-Installed DIS system (or moved ECM to a DIS-equipped engine) which RETARDED timing by 60°.
-Eliminated the unwanted RETARD by causing ECM to advance timing by an additional 60° (above the engine's timing curve) under all conditions.
-Raised the limit on maximum advance, to give the ECM room to calculate the high degree of advance from reference pulse to ignition event.
Since you know your DIS has a 60° retarded reference pulse, you can still use the Tuner Pro data to analyse the engine. Just look at the "spark advance relative to reference," which will show 60° more than the actual advance. Don't pay attention to the "spark advance relative to TDC" because that only applies to the distributor motor.
Before doing any hard driving, VERIFY WITH A TIMING LIGHT that the ECM is accurately controlling the timing.
Thanks,
David
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The more I read the more amazed I am that my engine even runs ! I think Six's advice is responsible for that. Thanks.
that is just the type of project we need here! It's amazing how adaptable these ECMs are.
