Idle fluctuating then stalls

[Eric0]

Hello, this is definitely my favorite forum. I always manage to resolve my issues when I come here!  However, I’m dealing with a problem I’m not sure how to address. I’m hoping to receive pointers or guide on my quest to solve this issue. 
 

Issue: On cold start, my swapped 180sx with an rb25det will crank and idle normally, but as soon as it starts warming up. There’s a subtle backfire, little pops if you will. At operating temperature, the idle begins to fluctuate up and down between 800-1200RPM. Eventually, only when fluctuating RPM it will drip my 150A breaker at the battery and the g4+ ecu will lose power and shut off.  Or the ECU will shut off without dripping the 150A breaker and everything else stays on: radio, fuel pump, gauges, etc. 

Questions:

1. What may cause the ECU to turn off?

2. How to I measure voltage to the ECU? 
3. Is it possible there is a short causing the current surge to drip the breaker and make the ecu behave erratic? 
4. Anything I should check?
 

Parts installed before problem began:

• GTR R35 Coilpacks 

• Bosh donut knock sensors 

• PRP trigger kit 

• 270A alternator 

• LINK G4+ lambda CAN wideband sensor 

 

I did drive the car with all parts installed with one issue.  The ECU had a wideband sensor overheated code, which I resolved by addding a 200uF 12V capacitor. Other than that, I didn’t deal with issues until this. 
 

Any help is greatly appreciated. Thanks!

Edited June 7, 2023 by Eric0
Added more description

[robbo_rb180]

The 150A breaker is it a quality item? Thats a big current trip

Does the afr change and go lean? sounds like a possible lean issue with popping or if rich check coil voltage.
Check IACV resistance when cold and warm. Also disconnect and see if same issue occurs.
Did you upgrade the alternator wiring when you did the upgrade?
Check wiring at alternator as could have a steel/braided line running over the B+ terminal

 

[Dose Pipe Sutututu]

Sounds like an alternator related issue.

What is your voltage like?

[Murray_Calavera]

Can you log every channel and post up the data? Would save a lot of guessing. 

[Dose Pipe Sutututu]

3 hours ago, Murray_Calavera said:

Can you log every channel and post up the data? Would save a lot of guessing. 

This!

[Kinkstaah]

Surely something tripping a 150AMP relay is a short somewhere?

[Eric0]

19 hours ago, robbo_rb180 said:

The 150A breaker is it a quality item? Thats a big current trip

Does the afr change and go lean? sounds like a possible lean issue with popping or if rich check coil voltage.
Check IACV resistance when cold and warm. Also disconnect and see if same issue occurs.
Did you upgrade the alternator wiring when you did the upgrade?
Check wiring at alternator as could have a steel/braided line running over the B+ terminal

 

Hi Robbo! Always lovely hearing from you! You’ve helped me with a lot of issues! 

Yes, the 150A breaker is quality and I’ve never had it trip until recently with the idling issues. All alternator associated wiring was upgraded to sustain high current. 

I just had Jono go over my ECU and he was able to pin point the triggers being a reason why the stalls out. The ECU had a lot of trigger errors. 

Not sure why the breaker went off, or ECU shut off, maybe due to bad trigger feedback? 

I will resolve the trigger issue and see if the weird behavior persists.