Cranking fuel tables

[Torque]

Hi ..

There is no cold start signal, just the ECU listening on the temperature sensor.
There is a cranking signal though ...

Is the ECU reading the temperature correctly?

[bachig24u]

its what happens when the cold start enrichment isn't sufficient.

happens after injector size increases and maf changes.

[BlueRB240]

Hi ..

There is no cold start signal, just the ECU listening on the temperature sensor.
There is a cranking signal though ...

Is the ECU reading the temperature correctly?

Sorry meant start signal. Yes temps are showing correctly.

[bachig24u]

I'll bet it has an eye watering exhaust until its warmed up also!!

had the same issue after a set of 870's were installed on a RB20 also.

took a while to sort cold start runnig characteristics.
still working on the cranking enrich tables as they took a lean dive suddenly after injector upgrade also.

fun times..

[Torque]

Interesting, why lean after bigger injectors?

So cranking and warm-up is not governed by the all mighty K-Factor?

[Matt]

No they are not

Well cranking start tables are in ms so totally independent of K constant

Usually after whilst warming K is somewhat used but the cold start enrichment tables are a % based calculation. K does not seem to have as much effect then on bigger injectors. So then usually cold start tables need tweaking to compensate for the larger injectors (pulling the tables leaner)

The issue I'm having with both my R31 and R34 is the air cond enrichment is not affected by K either. It means both are leaning out at idle with A/C on and will be part of my own personal quest to fix this problem to restore driveability (and then bring to the rest of the vehicle platforms)

[Torque]

Why not re-calculate these % values based on the change in K (when using larger injectors?)

[Matt]

The cranking tables are now automatically recalculated based on K %

However ... the warm start enrich tables etc have only been recently been identified as something which may need changing

Now if the injector resize is done followed by the MAF resize then it usually is not needed since K is about the same. However if K goes out of wack then it will. Would have to experiment with this one. In the meantime I'll leave that to the tuner since I've got more than enough other things to keep me busy at the moment

[Torque]

Hi!

I did a resize in version 13R, then did a compare.

The cranking tables did not change on a Z32 ECU.

(Warm Enrich/Cold Enrich)

Any suggestions?

The cranking tables are now automatically recalculated based on K %

However ... the warm start enrich tables etc have only been recently been identified as something which may need changing

Now if the injector resize is done followed by the MAF resize then it usually is not needed since K is about the same. However if K goes out of wack then it will. Would have to experiment with this one. In the meantime I'll leave that to the tuner since I've got more than enough other things to keep me busy at the moment

[Matt]

(Warm Enrich/Cold Enrich)

These are not cranking tables, they are enrichment tables. They adjust the fuel after cranking has completed and engine is running without the starter motor being used

[Torque]

Hi Matt!

Hmm ... but the table name said 'cold/warm crank' that's why I thought they were for cranking ..

So which tables are the 'cranking' ones then?
(On Z32)

Also whichever they are, I could see no difference in the resized map ..

[Matt]

'Crank enrich' is the table you are looking for

The other two tables are cold and warm enrichment tables. The one that gets used is determined by what the current coolant temperature is during cranking

Normally if < 15degC coolant then 'cold enrich' used otherwise 'warm enrich' used

Table names are 'Enrichment coefficient' when opened for 'cold' and 'warm' crank respectively. Table will highlight if Nistune knows what the cranking temperature is whilst consult connected

[Torque]

There are % tables going to 100% actually ..
(I don't have them here since I am at work)

Would you know what the % works on?

Is it % of K or % of mS?

That's right- some are purely percentage based. I've seen this on the CRO while bench testing. So if you have a value of 10 that means the injector will be open for 10% of the cycle. Go to 100 and the injector will be on all the time!

Bottom line is to be careful with these tables. Go in small increments and always adjust a group of cells rather than just one.

PL

[Torque]

From memory I don't recall such a table on Type 2, but I will double-check at home.
Thanks

'Crank enrich' is the table you are looking for

The other two tables are cold and warm enrichment tables. The one that gets used is determined by what the current coolant temperature is during cranking

Normally if < 15degC coolant then 'cold enrich' used otherwise 'warm enrich' used

Table names are 'Enrichment coefficient' when opened for 'cold' and 'warm' crank respectively. Table will highlight if Nistune knows what the cranking temperature is whilst consult connected

[Matt]

Called 'First Time Enrich' in the current version. Been updated on my machine... not out there yet