Hesitation at low throttle

K-Series Programmable ECU installation questions / support issues
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Xaser
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Joined: Sat Aug 29, 2015 12:43 pm

Hesitation at low throttle

Post by Xaser »

Hi there,
I really hate to be the guy whos first post i asking for help but I'm really struggling here.

I have a K Swapped EG thats been on the road for about 4 months. I did have a few teething problems at first like the classic idle issues etc but most of these problems were solved by reading threads on here.
Recently though the car has developed a bit of hesitation at low throttle between ~2-3k rpm. I have done the usual fixes with new plugs and coilpacks but to no avail.

I have also read that this is also quite common issue with dodgy TPS's, the one on the car was a brand new Honda OEM fitted when the car first got put on the road as the old one was damage. It was all calibrated when fitted so that no throttle produced 0% signal and at full throttle it produces 100/101% so I'm pretty confident thats good. I then did some data logging to see if the signal from the TPS was noisy, which seemed fine but i did notice that the ignition timing seems to go weird when the hesitation occurs.

Details
- K swapped EG with UKDM K20A2 out an EP3
- K-Pro 2 Serial 0309
- Kmanager 4.2.5
- ECU 37820-PRA-E11
- Running the stock calibration with tweaks just to remove EVAP, Immobilizer, secondary 02 etc.
ignition hesitation.jpg
Attached the cal and datalog

Thanks in advance,
Dave
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Last edited by Xaser on Sun Jun 05, 2016 3:28 pm, edited 1 time in total.
Xaser
Posts: 5
Joined: Sat Aug 29, 2015 12:43 pm

Re: Hesitation at low throttle

Post by Xaser »

I tried a few things today to see if they were the issue, first setting the car in open loop as it only seems to occur once the car has warmed up a little bit so thought it may be a dodgy 02, although it looked to be doing what it should to my untrained eye. Then tried disabling the idle valve in case it was doing anything spurious and again no change.

I can see a tiny bit of "noise" on the TPS signal but it doesn't seem to coincide with ignition going weird, so starting to wonder if this could be a crank sensor or pickup issue but i believe that the tachometer is derived from the crank as well and I can't see any strange going ons there either.

It also seem weird that when i look back at the datalog with the map it seems to say that the ignition should stay where it's at whilst the data log shows shooting up and down.

Thanks again, if you can provide any help it would be really appreciated,
Dave
Xaser
Posts: 5
Joined: Sat Aug 29, 2015 12:43 pm

Re: Hesitation at low throttle

Post by Xaser »

So after a more research today, it would seem what i am seeing in the data log is Honda's "Acceleration Smoothing Retard" covered here in the Hondata Help file https://www.hondata.com/help/kmanager/i ... meters.htm which is there to help reduce "bunny hopping" which seems to be exactly what it is creating for me when trying to accelerate slowly.

I will try disabling this or at least reducing the duration to see if this sorts my problem.
Still confuses me why this only seemed to have appeared/become noticable recently though :S.
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Hondata
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Re: Hesitation at low throttle

Post by Hondata »

Yes, it is the acceleration smoothing retard. It probably has been triggered by the TPS noise.
Hondata
Xaser
Posts: 5
Joined: Sat Aug 29, 2015 12:43 pm

Re: Hesitation at low throttle

Post by Xaser »

Was thinking that, so does this mean the noise on my TPS is excessive then? (the data log I attached definitely shows my TPS at its worst.) i'e does this mean its time to go down the root of a k-tuned TPS?

Thanks for the reply.
Xaser
Posts: 5
Joined: Sat Aug 29, 2015 12:43 pm

Re: Hesitation at low throttle

Post by Xaser »

Just thought I would close this thread off for clarity.
I went past my garage on my way home last night, disable the Acceleration Smoothing Retard and that sorted it, probably the nicest it has ever driven. So looks like after all this is was the TPS all along, there are still some little barely noticeable hesitation which look to be due to the TPS directly. It would seem my TPS has been slowly getting worse since I originally started looking into this problem, my original datalogs the TPS looked fine as that was my first port of call, then the one I posted here showed it not looking to great, but after disabling the Acceleration Smoothing Retard I can see some large spikes in the TPS which i think is causing these tiny hesitations that i still have (as can be seen toward the end of this plot, note: the TPS is scaled as i was only looking at low throttle)
TPS.jpg
So to sum up, thats a new TPS ordered, hopefully get it fitted at the weekend.
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Hondata
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Re: Hesitation at low throttle

Post by Hondata »

Thanks for the update.
Hondata
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