Help: RPM fluctuation making car jerk on low speed

[Prozento]

Dear CivicX community
I am experiencing some new strange RPM fluctuation in my car and hope you will be able to point the possible reason for this.
General info:
Car: Civic 1.5 sport HB manual
Tune: Triple 16.5/18/21 PSI (appear on all of them)
Early spool: off
Throttle response: 2
Improved spool: 2
Errors: only U129e disabled
Basic2step: 3600-3450
Maf: factory scaled option
BBG: 1/17; 2/19
IAT correction: 0,1,1.5,2,3
Rev-Hand disabled: No
Cruise control main unit while driving: off

On low speed with first/second gear, without touching the clutch (for example after passing a road bump), when I press the throttle pedal the car start to jerk for a few seconds until the speed rise and RPM fluctuation stop. Sometimes its happen when I go up to a hill on the same speeds. The RPM changes sometimes are near 100-120.
Adding picture from a log when you can see this happen: (have the whole log too of course)
https://ibb.co/MN1sbCn
After that I changed to factory tune and this stopped but not completely. Sometimes I do feel something similar but far to be that noticeable.

I spoke with Ktuner and he told me that possible reasons are:
1. Bad fuel (Look for a k.control) - K.control on stock is stable 0.49 and rise only on WOT. Waiting till tomorrow to finish my old fuel and used K44 fuel system cleaner to full refill. After all time spent on stock tune, I have a feeling that the fuel is not the problem, even that maybe some bad gas station could make it worse so I noticed there is some problem.
2. Fuel injectors - The car feels good and fuel economy without any change so I for now I dont think hardware is the problem, even that I can be wrong of course.
3. Spark-Plugs - same as 2

Does someone experience a same thing? What option(Q.adjusment in Ktuner) can make the jerk so more noticeable than the stock tune?

Thank for all who spent their time on reading all this and hope you will be able to point the reason for this
Sincerely
Prozento

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[Prozento]

https://www.civicx.com/threads/hesistation-stutter-at-low-rpms-tweaked-starter-21-ktuner.44508/

After reading this and hoping that I found the solution - Ktuner said that this is not the same case.

So hope you guys can help me to point the problem

 

[Prozento]

Hello everyone
Here are an update about the issue.
First of all I flashed again the triple 16.5/19/21 Beta version tune (in place of stock) with the maxed adjustments, early spool and MAF factory scaled (used 16.5 psi map while testing).
After driving just for a few minutes I immediately experienced the same issue as before - jerkiness on second gear. The car feels jumpy on the first gear too and you can diffidently see it on the logs.

When I understood that the issue is still here, I flashed the 21PSI Dual Eco Non-Beta version.
Again immediately drove to the test area and hallelujah, there is no issue at all. It is even better than the stock! Before I came back home and opened the logs I tried to duplicate the issue on this tune - but nothing happened. It works fine.
When I came back and watched the logs I saw that in this tune the TPSCMD never pass the TPS under 1500, it is always under the actual TPS (opposite from the Beta tune). It does pass the TPS after 1500 RPM sometimes (on WOT for example I saw it almost always).

So it looks like the problem is in the BETA files. At least I cant find any other explanation for the difference between the tunes. There is something about this maps that just aint right.
Anyway, after spending few days of testing I came back to the starting point - waiting for the full version to my ECU 5AN-E32 . Hope Ktuner will release it soon.

Sincerely
Prozento

 

[KTuner]

The same fix was applied to all codebases the same way. The starter tunes for non-Si are all the same for any given codebase you choose to work with.

I was very clear in this post. The factory limitations have been reintroduced and we will not be introducing any limitations beyond factory.
https://www.civicx.com/threads/hesi...ed-starter-21-ktuner.44508/page-2#post-736907

Feel free to find a combo of quick adjustment settings that works for you or choose to use the non-beta option. That is your choice and luckily you have it!

 

[Prozento]

The same fix was applied to all codebases the same way. The starter tunes for non-Si are all the same for any given codebase you choose to work with.

I was very clear in this post. The factory limitations have been reintroduced and we will not be introducing any limitations beyond factory.
https://www.civicx.com/threads/hesi...ed-starter-21-ktuner.44508/page-2#post-736907

Feel free to find a combo of quick adjustment settings that works for you or choose to use the non-beta option. That is your choice and luckily you have it!

I am never talked about factory limitations. This is something beyond my understanding.
I just point that the logs from 2 tunes that supposed to be similar - is different ...and it have nothing to do with quick adjustments! I have tried them all already. The BETA files and Non-BETA files have something different in their core.

I will copy-paste my ongoing journal of the tunes testing:
Tune 1: Non-beta 21PSI dual eco/factory
Throttle: Adjustment closed (factory?)
Improved spool 2
Turbo responsiveness 3
Boost ramp: Aggressive 2

NO jerking at all (logs from the previous post)

______________________________________________________________________
Tune 2: Beta Triple 16.5/19/21PSI
Throttle: Factory
Improved spool 2
Turbo responsiveness 3
Boost ramp: Aggressive 2

AVERAGE JERKING ON 1300-1500 RPM

______________________________________________________________________
Tune 3: Beta Triple 16.5/19/21PSI
Throttle: Economy
Improved spool 2
Turbo responsiveness 3
Boost ramp: Aggressive 2

LIGHT JERKING ON 1300-1500 RPM

________________________________________________________________________
Tune 4: Beta Triple 16.5/19/21PSI
Throttle: Improved 2
Improved spool 2
Turbo responsiveness 3
Boost ramp: Aggressive 2

HEAVY JERKING ON 1300-1500 RPM (logs from the previous post)

_______________________________________________________________________


Its clear that one of the Graphs acting different between BETA and Non-BETA tunes.
I understand that the same fix applied to all the codebases, but what if the codebases wasn`t the same from the beginning? Since I have found differences between couple of tables - maybe the codebase used for BETA files is different for this specific ECU than the Non-BETA one? Just guessing

 

[Prozento]

Here are another test I have made:
Tune 1: Non-beta 21PSI dual eco/factory
Throttle: Adjustment closed (factory?)
Improved spool 2
Turbo responsiveness 3
Boost ramp: Aggressive 2
A/C: on

All the logs, even when there are some fluctuation in RPM, TPSCMD stays under the TPS on low RPM. No jerking problem at all - same as stock

*I have tons of other examples and the whole log of course

Now switching to another tune: (I use this tune since I assume its the closest to the NonBeta file)
Tune 2: Beta Triple 16.5/19/21PSI (16.5 used for testing)
Throttle: Factory
Improved spool 2
Turbo responsiveness 2
Boost ramp: Aggressive 1
A/C: on

Car stutter again and the logs came back to the "Beta behavior":

Its really acting not in the same way

Another interesting observation. These 2 samples were made in the same place - climbing small hill before turning left
BETA:

NonBETA:

no words need to be added in this case I think

 

[KTuner]

Dial back your quick adjustments to something that works for you.

One of your starting tunes is labeled beta, which is the one you're complaining about. If you're unhappy with the beta option, don't use it. Use the non-beta option instead. Thanks for sharing!

 

[Prozento]

Dial back your quick adjustments to something that works for you.

One of your starting tunes is labeled beta, which is the one you're complaining about. If you're unhappy with the beta option, don't use it. Use the non-beta option instead. Thanks for sharing!

Thanks for an answer
Last 2 question:
1. If I will choose to stay with the BETA version, is it still safe despite this issue (considering the fact that this is my daily and I drive quite a lot)?
2. Will it have some negative affects on the engine in a long run? (Or at least until you will publish the full version hehe)

 

[julianzh]

On boost by gear, set gear 1 to 17psi. It help out a lot on my Civic. My car always jerk during slow traffic or stop and go traffic. Limited 1st gear to 17 psi made my commute so much smoother. Works on base map and TSP map too.

 

[KTuner]

We have some datalogs from the customer, but you may be on to something. Loading factory boost levels does not cause the change, so potentially limiting lower gears could add some relief if this is caused by the ECU's boost control which integrates directly with the throttle control.

 

[Prozento]

I would like to thank Ktuner for taking part in solving this issue. I really hope that your efforts will end up in something useful.

It shouldn't be taken for granted that Ktuner community is getting customer support on that high level. Most of the times in my country it looks much more like "You paid, have a nice day"


P.S. As for the BBG. It was set for 17PSI for first gear and 19PSI for second gear. Since this is really high I guess I should try it much lower and close to stock

 

[CAPTS]

We have some datalogs from the customer, but you may be on to something. Loading factory boost levels does not cause the change, so potentially limiting lower gears could add some relief if this is caused by the ECU's boost control which integrates directly with the throttle control.

looking forward for beta/full support for 5AG - P6/9X
have people asking for pop/bang setup (not recommended but there's some asking for it)
personally looking forward for more tables to be accessible especially BBG to limit lower gears

 

[Prozento]

With the help of Ktuner this issue has been solved. I want again to say a huge thanks for the help. Great customer support and great product.

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