Nistune Forums

Is there any Low AFM signal voltage setting to trigger limp mode ?
Could it be modify ?
I see if the signal lower than 1.040V, the mixture will goes rich.
I'm tuning a CA18 with Z32 AFM, can't get proper AFR transistion from 700rpm to 900rpm while idle switch is on.

N13? I didn't try that , but B13 SR20DE has Low AFM Voltage Enrichment Trigger which help in same situation. It is in expert mode all way down ...

There is a low voltage check of 0x0008 * 50mV = 400mV at address 8673 in the code (36F05) for the MAF DTC trigger

After this there is a check 0x014 x 50mV = 1000mV at address 86AB in the code which I think is the low voltage you are hitting. Only changing the code directly can alter that

Matt wrote:There is a low voltage check of 0x0008 * 50mV = 400mV at address 8673 in the code (36F05) for the MAF DTC trigger

After this there is a check 0x014 x 50mV = 1000mV at address 86AB in the code which I think is the low voltage you are hitting. Only changing the code directly can alter that

Hi Matt,
Is it possible to change address 8673 and 86AB in the HEX editor ?
The rom image I can access is only from 0000 to 3FFF.

skylinegtrhr wrote:N13? I didn't try that , but B13 SR20DE has Low AFM Voltage Enrichment Trigger which help in same situation. It is in expert mode all way down ...

Hi skylinegtrhr,
That is S13 CA18DET.

interested in this too

See how louis goes with the code changes I've emailed him

ok thanks

Matt it's possible that any of the flags like bit 1,bit2 etc could be this low voltage enable/disable?

Not likely for CA18 as it is all hard coded. Later models moved the voltage checks into separate parameters which we can modify but not this earlier ECU

Matt have you identified all the flags on ca18 ecu?

Not at this time. I'm looking at SR20s and RBs at the moment

I have the exact same problem with my S13 CA18DET with Z32 AFM.

Could you explain how I can solve it?

I've got louis email in my inbox so I will start looking into it this week. At this stage there is no solution for the issue

not sure if this is solution,but you can find here schematic of my diy device that add adjustable voltage to the AFM output signal. This can prevent limp mode that causing your issue,as you can define minimum AFM voltage.