Cranking fuel tables

[Nuyskov]

Hello, Matt!
There are a few tables about Cranking in Nistune (0V810 ECU):

Crank Enrich (%)
Crank Enrich Offset 1 (ms)
Crank Enrich Offset 2 (ms)
Crank Enrich Offset 3 (ms)
Crank Enrich Offset 4 (ms)
Engine Crank Offset (ms)

As I understand Crank Enrich table tells ECU how much fuel needs engine to fire up during cranking. And this table is independent from K and Latency.
And what make other tables?

[Matt]

I've been looking into this for another customer just before christmas. With regards to the crank enrichment tables, these are used conditionally.

Meaning that depending on various inputs will depend which table gets used, or how much the table has an effect. As such it is difficult to work out, and changing tables sometimes have varying effects depending on how the vehicle is started.

I’ve dug further into the code after updating the symbol tables further:

Crank enrich – appears to be the main table

Crank Enrich 1 (value saved from this table does not appear to be used in the code)

Crank Enrich 2 (value from this table is used as a multiplier)
*Crank Enrich 2. The multiplication is changed if TPS is open/closed (Digital control 1, #01 clear)

Crank Enrich 3 (value from this table subtracted from multiplier when no start signal present. Digital Control 1, #02 clear)

Crank Enrich 4 is always referenced. Table is indexed based on RPM. Multiplied by value from Crank enrich 3 table

Notes: Crank Enrich 1-3 are is not referenced when no start signal is present during cranking (Digital control 1, #02 clear)

Basically from the above. Crank Enrich 1 doesn’t need to be changed. Other tables are used and their usage depends on timing of the start signal to the ECU, cranking length and position of the TPS. Sometimes coolant temperature can also come into effect with ECUs but I don’t see that here in the code

Regardless I normally suggest to reduce the cranking tables values by the % of fuel injector increase, so it is adequately compensated for. Crank enrich offset 4 and the main table are the ones I would recommend to modify by this %

[Nuyskov]

Thank's!
Will try to see what depends on their changings and tell you if I find new relationships.

[Matt]

I need to adjust my R34 further with these also. Sometimes it takes longer to crank than it should