Car is bucking at low RPM

[Friendly]

2004 Honda Civic LX w/ 2002 K20A2 & 2006 K20Z1 Tranny
Not sure of serial number
37820-PRB-A05
V3.3.1
K&N short ram, 4-2-1 header, No cat w/ 2.5" exhaust.

Recently my car has started bucking at low rpms (1800 - 2500).

I am new to the KPRO. It came with the engine and I finished the swap about a month ago. I never noticed this problem before.
My calibrations came from a stock map downloaded from KPRO and some cam changes from a cold air intake dyno tune also from KPRO.

I would appreciate any help or guidance as to what I can try to d to fix this problem.
Thank you so much.

I attached 1 zoomed data log of the bucking (WTFisthisshitZOOM);
1 long data log of a 10 minute cruise (WTFisthisshit);
1 short log of a normal 2-4th pull (WTFisthisshitPULL);
and my current calibration (8300);

[Spunkster]

Please see the Help file about acceleration smoothing retard:

http://www.hondata.com/help/kmanager/ge ... =gear+comp

[Friendly]

Please see the Help file about acceleration smoothing retard:

http://www.hondata.com/help/kmanager/ge ... =gear+comp

Hey, thank you!

I did notice that my ignition was retarding a lot around the time when the injectors where acting up.

Quick question however. Would the ignition retarding affect the injectors to cut like that?

I noticed that bucking only when the injectors where cut. Other times when I was driving and the ignition was retarding, I did not notice and 'Bunny hopping' as the Help file mentioned.

I will still go ahead and make some corrections and post results, I am just trying to learn how the KPRO works at the same time.

Thank you again!

[Spunkster]

Start with this and see if it fixes the issue.

[Friendly]

Start with this and see if it fixes the issue.

Hey,

So I went ahead, and just completely removed all tip in retard duration, as well as set all the tip in retard gear multiplier to -100.

My ignition graph is a lot smoother, however, I am still getting the hops from the injectors cutting every now and then. Although from what I have experienced so far, it is not as much as before. Thank you for that.

But do you have any other ideas for what could be causing this problem?

Thank you again!

Attached is a new data log. As you will see the ignition line is much smoother compared to before (except at idle) but there are still injector cutoff points.

[Spunkster]

Where specifically in the datalog is this happening?

[Friendly]

Where specifically in the datalog is this happening?

Wow, I am so sorry, I didn't mean to upload such a long datalog for you. Here is the corrected one.

I marked the instances that I felt with a comment "JUMP". You will see compared to the first one it is much less.

I also attached my current modified configuration in case there might be something in there.

[Friendly]

Actually, I just noticed that, at the times when it bucks, my TPS reading drops to zero.

I am going to go home after class today and check out my TPS sensor to make sure everything is ok with it.
The results are consistent with closing the throttle, so that could very well be the issue. If you have any ideas on this theory please let me know and thank you so much for your help!

[Friendly]

Sorry to resurrect an old thread.

My problem with the ijectors cutting had progressively gotten worse and worse.

I finally got a new TPS sensor and installed it on the car this morning. However my issue is still there.

Just an update on the problem:
At low throttle input (1-5%) the injectors will randomly cut off and then come back on. This causes my car to buck, and it is almost impossible to drive at any steady speed.
I had noticed that whenever that happened, that my tps reading would drop to zero. Which led me to change my sensor. However even with the new sensor, only a couple minutes of use, it started dropping to zero again as the car warmed up.

Does anyone have any idea of what I can do to fix this problem?

Side note:
This only happens when the car is warmed up.
My car has no oxygen sensor.

Quick edit:
In the datalog, you can see where the injectors cut, the tps reading will also drop to zero, and as soon as the injectors come back on, so does the tps.

[Spunkster]

It could be a wiring fault affected by heat.

[Jsandoval84]

Friendly I know this is an old thread but I wanted to know if you got this figured out. I'm having the same issue.