Throttle latency on 2009 k24 MT

via
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Joined: Thu Oct 26, 2017 8:13 pm

Throttle latency on 2009 k24 MT

Post by via »

I purchased a Ktuner V1 last week because I've read how it can greatly reduce the input lag and rev hang issues present on these cars. For the most part, it is significantly better. I have changed throttle compensation for fuel cut to 0%, have adjusted the fuel cut delays to 10 for all gears, and tried to configure it so that fuel cut doesn't occur below 3700 rpms. I have also created a 1:1 DBW mapping table. In general, it is much more crisp on gear shifts.

However, the issue is still present, and worst, it seems to be inconsistent. Sometimes the throttle is very precise, but other times the ECU is clearly ignoring my pedal inputs. I took data logs to try to figure it out, here are a few graph screenshots: https://imgur.com/a/mNFhC

Some of the examples in there are really obnoxious, such as when modulating the gas to get a quick start and the throttle clearly does nothing.

Is there any way I can solve this with KTuner? Looking at the logs it does seem that when the clutch has been used, or a gear shift is occuring, it is a crisp precise throttle response, and when it isn't a gear shift, such as in just cruising at low load and rpm, the inputs are heavily filtered. I was considering bypassing my clutch pedal switch to see if that made a difference, but I don't really want to eliminate cruise control by doing that. It would be really great if KTuner could somehow keep this from happening. If there's any data I can provide that would help, I'm more than happy to.
KTuner
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Re: Throttle latency on 2009 k24 MT

Post by KTuner »

Try starting over with a fresh tune, because it doesn't do what your logs are showing even factory. If you still have the issue I couldn't begin to tell you where to start looking, but you have a problem somewhere.
via
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Re: Throttle latency on 2009 k24 MT

Post by via »

Huh, thats odd -- it definitely was doing this before KTuner, I assumed it was intentional throttle input filtering to "assist" people who didn't know how to drive a MT. Are you thinking something mechanical?

edit: I guess it would help to know if TPS.CMD is what the ECU is instructing the throttle to do, or the reported throttle position from the throttle body.
via
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Re: Throttle latency on 2009 k24 MT

Post by via »

I've got to admit, this seems like the exact same problem that a lot of other people have with respect to nonresponsive throttle, sometimes you press the gas and it just doesn't react. I've read lots of forum posts, and also (for the newer accords) hondata products with corresponding graphs that show the exact same throttle ignoring and lag that I see here, and how it fixes it. I can easily reproduce this by just driving at 25 mph in 2nd gear and very quickly pressing and releasing the throttle. Most of the presses will be totally ignored, but some of the presses will be responded to -- its like its trying to filter out accidental rapid throttle presses. I can reproduce it at any rpm.

I realize ktuner might not have a fix for this, but it would be really nice to investigate it and see why it happens, there must be some conditions where the ecu wants to heavily filter throttle input.

Edit: see https://www.hondata.com/forum/viewtopic.php?p=66231
KTuner
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Re: Throttle latency on 2009 k24 MT

Post by KTuner »

TPS is the throttle and TPS.CMD is what the ECU is commanding. We've tuned and worked with many of these vehicles. Lag is not something I recall seeing at any point during factory testing before tuning, or when tuned.

That being noted, we actually don't adjust throttle settings at all in our tunes. Email a log with our base tune loaded onto the vehicle. I'll take a look at it.

You are speaking about more than just taking off in first gear, right?
via
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Re: Throttle latency on 2009 k24 MT

Post by via »

Thank you -- yes it seems to be an issue in pretty much any gear. The most annoying part about it is how it seems inconsistent.

I'll load the base tune and give a log later this afternoon, much appreciated.
KTuner
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Re: Throttle latency on 2009 k24 MT

Post by KTuner »

No problem. Don't tweak any settings in the tune for the log you submit. If it's inconsistent I'm not sure it's going to be part of the ECUs command code.
via
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Re: Throttle latency on 2009 k24 MT

Post by via »

I'm sure its consistent with however its programmed, I just don't know what conditions it chooses to do it under, so it just feels really horrible from my perspective.

Either way, log is attached with a factory base image loaded and me driving up and down the road. You can see that throttle response is often horrible with giant lag times opening the throttle. In the log I do a lot of pulsing the throttle and you can see it sometimes doesn't touch the commanded TPS.

Also pictures: https://imgur.com/a/cCDpT

Correction, it won't let me attach the log, its 4 MB. Can I email it to you?
KTuner
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Re: Throttle latency on 2009 k24 MT

Post by KTuner »

TPS isn't supposed to match TPS.CMD all of the time. It's based on the drive by wire tables.

Email was what I asked you to do in the earlier post.
via
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Re: Throttle latency on 2009 k24 MT

Post by via »

What is your email address?

I know it doesn't match, but clearly that is not any form of mapping going on in those graphs, and my earlier graphs were from a linear mapping.

edit: I sent things to info@ktuner.com, let me know if you want it elsewhere.
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