Nissan ECU Tuning

lamarmarani. · Joined: 13 Apr 2004 Posts: 51

Does anyone know how the cold start map is used on the CA18DET ECU? I need to reduce the fuelling during warm up in my application.

I think the enrichment table is at 3EB0-3EBF in the ROM - does anyone know the temperature for each value?

Apparently theres the temp sensor calibration table at 39E0-39FF, where the value in each cell is the temp in deg C - 50 - i.e. temperature = (value in cell - 50)

I'm guessing I'll need to reduce the values in the enrichment table, but it'd be good to know the temperature that each cell represents.

Sileightysx · Joined: 03 Apr 2005 Posts: 22

16 byte water temperature based tables are -40 to 110 Deg.C. in steps of 10 Deg.C.

lamarmarani. · Joined: 13 Apr 2004 Posts: 51

Excellent - thanks a lot Smile

Sileightysx · Joined: 03 Apr 2005 Posts: 22

I believe that 3EB0-3EBF is TKAS starting additions.

3EE0-3EFF is TKTW warm up additions. Scale is based on water temp. it should be the same as 16byte tables except 5 Deg.C. increments iirc.

lamarmarani. · Joined: 13 Apr 2004 Posts: 51

Ah right - I'll try changing both and see what happens.

Any idea why neither map has zeros when the engine is up to temp?

LMQT · Joined: 06 Aug 2005 Posts: 144 Location: France

Please, could you explain "TKAS" and "TKTW" and "iirc" ? Razz

Thanks

_________________
200SX RS13 Zenki (w. CA18DET)
280hp & 330Nm @ 16PSI (GT25R)

datsunboy · Joined: 26 Jul 2005 Posts: 209 Location: New Zealand

iirc is just "If I Remember Correctly"
_________________
1970 Datsun 1600 CA18DET Project

The point of life is not 2 arrive at your grave all preserved & in mint condition, but 2 slide in sideways, scratched & bruised screaming F**K WHAT A RIDE!!

Sileightysx · Joined: 03 Apr 2005 Posts: 22

LMQT · Joined: 06 Aug 2005 Posts: 144 Location: France

Sileightysx · Joined: 03 Apr 2005 Posts: 22

openloop · Joined: 22 Dec 2005 Posts: 81

If sensor goes from 0 to 5v

Voltage VS temp correction goes from 0 to 255.

you do value -50 and temps go from -50 to 205

How do you know enrichment table goes from -40 to 110 and not -50 to 205 ?

cb_drift · Joined: 04 May 2004 Posts: 472 Location: New Zealand

Two things Smile

a) could someone copy the fsm page to disk and then upload it using the attachment function in the forums - i get asked for a username and password to view the pic - im guessing other people do as well Smile

b) the range -50 -> 110 in 10 deg steps gives you 16 steps - normal table size. also these steps are a range - not an absolute - so if you are at -60deg - you use the setting calibration for -50deg - and why would you want to live there anyway? You dont? no need to worry Smile

same if you go over 110deg - it will use the calibration for 110deg for anything over it - at that temp your engine is cooked anyway - it wont be running (and if it is - it wont be for long)
if you calculations say you cant get an exact -50 deg - ass its all interpolated anyway - it wont matter if the calibration is out 1 or 2 deg - as the compensation tables will correct that anyway - the whole car is tuned around the calibration maps - so the end result is what matters - not the values on the maps - (otherwise the fuel tables would like up to real world af ratios when you convert them from the factory maps - it doesn't take much to make them correct like that ....)
hope this helps

openloop · Joined: 22 Dec 2005 Posts: 81

Thanks, I see what you mean, no problem,

But my question was how do you know range is -40 110 and not -30 120 or -50 100 or anything else.

I ask you because if I want to ajust around 0° range, I must know where to locate it in the table, maybe you experienced it yourself by tuning this vector step by step while monitoring you water temp. Just tell me.

Thanks Wink

cb_drift · Joined: 04 May 2004 Posts: 472 Location: New Zealand

fsm mentions it somewhere and hardware trace shows me with consult what is being read and what the water temp is for it...

openloop · Joined: 22 Dec 2005 Posts: 81

OK, many thanks! Wink