Start tuning SR20DET

[Matt]

2022-07-01 15_33_36-Nistune [S14A(SR20DET) (Version_ 1)].png

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This point here is where it goes south. The MAF is still reading a voltage shwoing load (about 1.5V) whilst RPMs keep dropping below 800

What you see next is an increase in TP load (green) and injectoin time (orange)

Either put a bend between the turbo and the MAF (turbo probably still spinning and sucking through airflow, measuring load) to reduce the affects

Or update the firmware to FP1.1 or FP2.1 and use the antistall (TP limit table) so when TPS below the voltage in the table, we limit how far TP increases

[Skyline8075]

Do you think I can adjust anything else such as tpmin or something to fix? Just started to have this stall problem when I changed my cams. I feel like its a fueling problem with the cams giving it more air or maybe tps? The tps seems real erratic and i was really trying to baby as much as possible. I don’t even feel like boost had even started at these low rpms.

[Matt]

The TPS signal is slightly jittery. The only potential causes of that could be an issue with the 5V power/ground back to the ECU or the signal wire (assuming it is shielded all the way to the ECU). As usual start with the plugs/connectors and make sure secure and clean

If you hold it steady, the voltage should stay still on the TPS signal

Any extra airflow measure will result in more fueling, so that is something to consider, but we do see that MAF voltage hold quite high all the way through. Almost like turbo sucking airflow, or a leak

TPmax will limit injection time, but you can only really adjust it on the bottom end since it affects acceleration. That is why I added the 'anti stall' TP limit tables which get used when the throttle is under a certain voltage and then it stops TP cursor moving any further right

[kamilp1908]

And all working I have done with tunning the engine came to this result:

wykres200sx.jpg

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Boost is 1.25B (~18 psi)

[kamilp1908]

Hi.
I need to dig out my old topic

I have lately some problem with TPS and idle.
Main problem is that, when I setup my TPS at idle with 0.44V, there is no TPS Idle indicator lighting up.
It lights up when I set TPS below 0.3V. This is sth new for me, because it does not match to Nissan manual.

Is my TPS dying? Or maybe some ground problem?

[Matt]

TPS could be an issue.

When you crank, it records the TPS voltage (for idle position). If your TPS opens and then closes, and goes below this value (undershoot), then a new idle TPS position is recorded.

We have seen some cases where if TPS snaps shut, it undershoots and returns after to 'normal' position and no longer shows TPS idle

You can try this by cranking, check TPS idle set, note TPS voltage

Increase TPS slowly, and then decrease slowly to original voltage noted at crank and see you have TPS idle still

If so good, then try snap open and close and see if TPS idle gone. If so then loose throttle/TPS is causing undershoot issue and may need repair/replacement