Changing the ignition dwell time

[WalknBullzEye]

Is it possible to change the ignition dwell time in NIStune with ECU 71Y05?
I upgraded the original ignition coil for a low resistance coil with higher voltage output. That's why I need to adjust the dwell time.

Second question, does anybody knows what the function is of this resistor?


Third and last question. Is it true, our SR20 ignition control modules measures and controls the current (amps) to the ignition coil (primary side)?
Or is the resistor from the image above a tool for the ECU to know how big the current to the coil is? If so, then the ECU will control the current.

You can see the current is 6A max. And takes 4 mili seconds to reach, at idle RPM (stock coil):

[bachig24u]

looks like it's there to prevent damage to the ECU from the feed back from the coil.

Measure pin 3 to transistor and see if resistance is very high value..
That will tell you if its there to gnd/feed a small current to let ECU know if transistor is ok, so it doesn't trigger an ignition DTC.

[Matt]

1. Yes change the dwell using the dwell vs volts table. Increase the whole table values to increase dwell. Some ECUs (not this one) I've added code to read a memory address from the ECU and divide by RPM to display approximate dwell time

2. Resistor is used for ignition feedback. It is used by the ECU to determine if there is an ignition fault based on the signal from feedback of the coil. If so then the DTC is raised

3. I dont know the inner workings of the feedback. I have not seen in the code (so far) any change to the dwell calculations in determining pulsewidth in the RB20DET or SR20DET models, which dont have this resistor. I cannot comment on the code for the SR20DE model

About 4ms seems right for normal Nissan coil charge time

[WalknBullzEye]

Thanks for your quick answers!

Matt, what do you mean with "DTC is raised", what is "DTC"?

I found both maps to change the dwell time vs. voltage and rpm:

[Matt]

Diagnostic terminal code = fault code

When a sensor operates outside set conditions, a DTC is raised and displayed by the ECU LEDs (if it has them) and also fault codes are displayed in Nistune

Yes you adjust coil/volt table (first one)