KTuner V1.2 data logging showing boost way over target?

[turbotiger123]

Hey guys.

I recently flashed the Starter Dual Target 21 PSI Tune to my '18 Hatch. I did enable "Quick Adjustments" and set tune1 -> 17 PSI, tune2 ->19 PSI and tune3 ->21 PSI. I was logging (via bluetooth to TunerView) just for kicks and noticed that there was a spike to 24.05 PSI while running tune1 (jumped from 17.7 to 24.05 BACK down to17.19 in ~ 100ms). I'm hoping this is just a glitch with the data logging. Has anyone else noticed any quirks like this?

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[Crab]

Are you sure you are reading in PSI and not mBar? If we take the 24.05 as mBar, 2405 mBar - local Baro pressure of 1024 mBar = 1381 mBar. Converted to PSI that's 20.0 PSI. Still seems like a little over boost for a 17.0 PSI map.

Did it seem feasible for the boost pressure to change in the time frame you saw?

 

[360glitch]

I'm curious, do you have a catless downpipe?

 

[KTuner]

The more aggressive you get on adjustment settings, like RAMP, Responsiveness, and Spool, the more aggressively it will try to reach the target boost level. With PID boost control there is always the possibility of slightly overshooting and having the ECU correct for that to reach the target.

 

[turbotiger123]

Here's my datalog. The 24 PSI of boost is seen @ timestamp 1272.261 (row 26547).

I have not made any hardware modifications to my car.

 

[gtman]

I generally see a slight overshoot in hitting the boost targets from time to time. Basically 1-2 psi higher. But, overshooting by that 7 PSI is fairly drastic. I didn't look at the datalog but 24 PSI when you're targeting 17 is like a 40% overshoot. And honestly, your quick settings on that 17 PSI tune look fairly mild.

For comparison, a 40% overshoot with a 21 PSI boost target would be like 29+ PSI. Yikes. Have you datalogged your 21 PSI tune #3?

 

[turbotiger123]

I did log some 21 PSI pulls and saw around 22.8 PSI max.

Is it possible that the ECU can get "overloaded"? When that 24 PSI boost kicked in traction control was going bonkers due to a wet road surface. I wonder if the ECU was too busy dealing with traction and let the boost control "slip" a little bit...

 

[gtman]

Since it just lasted a second, might just be a one-off type thing. Have you done any new logging with the 17 PSI tune?

 

[Crab]

I took a look through the log. I'm no expert tuner, but that looks like a glitch in the reported pressure, or the log. Map did not jump at that time and it only happened for a brief moment. Definitely something to keep an eye on to see if it is repeatable.

 

[KTuner]

Since the target suddenly jumps to -3.9, which isn't accurate, I suggest that's a glitch. If you see a glitch again let's test some conditions for why that may be occurring.

Then again... this is a TunerView log output, so there could be an issue there vs the V1.2

 

[alxgravel]

We got a si and a hatch .... we are both on dual map starter / 21.5 psi

On my si I pulled 22.5 psi sometime to reach the peak target

My friend on his hacthback pull sometimes 23 psi

We make a conclusion for the hatch need to push a little higher to get his peak target because the smaller turbo

Hitting 1 or 2 psi sometimes its maybe normal ... but over that maybe something wrong. You sould reflash ur 17 psi tune if ur constently hitting 24 psi ...

We both use ktuner v1.2 and tunerview

 

[ergoodfellow]

Hi
I have a 2020 Hatchback 1.5 on the KTuner 21psi basemap. Was out on a late night drive when I felt a weird reduction in power. Continued driving and the car didn't feel like it was running right. I noticed MAP pressure was spiking up to 27psi, which I have never seen it do before. This is when I started logging. Turned off the car and turned it back on a few mins later and everything seemed to be working normally again. Let me know if you notice anything.

Thank you

 

[gtman]

Based on even that little 40 second blip, for sure something is wrong.

1.3 knock control. Boost is really off. It's taking a while for boost to happen and then when it finally catches up ... big overshoot!

At the 27 second mark:

At the 29 second mark:

 

[ergoodfellow]

Based on even that little 40 second blip, for sure something is wrong.

1.3 knock control. Boost is really off. It's taking a while for boost to happen and then when it finally catches up ... big overshoot!

At the 27 second mark:

At the 29 second mark:

Thank you for the quick response. Any idea what could be going on? I knew something was off immediately. I haven’t driven the car today yet. Last night it seemed to have fixed itself, but I’m not sure if I should still drive it.

Do you think it could possibly be a failed spark plug or injector?

Update: I went on a 15 minute drive. Knock control started at 1.05 and settled down to .83 once I got to my destination. Knock count was 1 and LTFT was -4%. Went WOT 2 times and boost went right to 21 and did not exceed. I wonder if something sent the car into a sort of limp mode last night, because it seems to be back to normal since I turned it off and back on.

 

[KTuner]

The wastegate is what controls boost pressure. You could also have a pressure leak which the boost control system is trying to compensate for. Check for loose connectors.

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