Hondata

Hey guys, so the title says it all. ive been having this issue for some time and working on it on and off, confirmed and checked many things and also scrolled through many threads on the internet for similar issue but not quite the same problem as im having.

Here are some specs:
k20z3 Dc2 on kpro v3 tuned
motor is internally stock as is trans/clutch etc
rywire kswap harness, ktuned conversion harness
k tuned fuel system but stock injectors 255 pump
karcpets adapter plate with stock tb with new oem iacv and k tuned hall affect tps
hybrid intake, karcepts header oem type s o2, 3in ss mandrel bent exaust to a vibrant uqr
using the ktuned vss calibrator as well if that matters.

My issue is that when the vehicle is warmed up to 180 the idle will drop to about 500-650 range only when rolling, the second i come to a stop it shoots back up to the target idle perfectly, the car has absolutely no drive-ability issues or CELs present. I checked a lot of wiring for the o2, vss, tps everything is in order with no resistance issues, as well as the components themselves are new. i have oem coil packs and spark plugs new as well. At this point i am wondering if it has something to do with tuning. This issue did not make itself present until i had a tps and iacv issue where i ended up replacing both as the bearing in the iacv was unable to spin freely even with cleaning as well as the tps simply going bad. After replacing and calibrating everything was fine, this was earlier this year during colder weather so the problem had not shown itself.
one thing that bothers me is im unable to determine my a/f ratio even though i have my o2 setup with built in wideband oem on kpro, i have some photos i will attatch to this thread.

some more photos

You need to post your calibration as well as a datalog showing the problem. Screenshots do not show the whole picture.

my apologies, here ya go

Spunkster wrote: Mon Aug 05, 2019 4:52 pm You need to post your calibration as well as a datalog showing the problem. Screenshots do not show the whole picture.

uploaded..
also yesterday when driving the vehicle i noticed when it was on the colder side of ambient air temp and water temp the rolling rpm would be raised slightly to around 1200 steadily. showing signs of the exact opposite as compared to reactions when warm

reviving this because i cant seem to find the issue with my concern. im going to try switching to countershaft style knowing it shouldnt work and seeing if the issue actually goes away. with that being said im going to assume it could possibly be related to vss? very very strange issue, hopefully someone has a little input

edit- for the record i have since only tried zeroing out the low cam angle speed below 1500 and from 1500-2250 i interpolated but that did not seem to fix the issue.

Are you sure that you have completely bled the coolant system? If there are any air bubbles it could cause idle issues.

Yes i have absolutely no air in the cooling system.

Perhaps calling this an idle drop was an incorrect use of words.

The vehicle itself has no issues with idle characteristics, it is only as the vehicle starts to roll that the RPMs begin to drop to 650 when warmed up. the second the car stops the rpm will recover to 850. the only difference when the vehicle is cold is that the rpm will raise to 1150 and again once stopped recover to 850.

the vehicle does not need any input what so ever for this to occur, just simply keeping it in neutral and releasing the e-brake allowing the car to roll is all it takes for the affect to occur.

At this point the only things that i feel could be causing this are either vss related, iacv related(although i have a new one), or something to do with closed loop. perhaps i am not setup correctly although i do have the correct oem o2 in place i also do not seem to get a value on the a/f display

Have you adjusted the idle valve duty adjustment slider?

yes i have adjusted that already, this weekend im going to review the wiring for some things again just to be sure. id really like to see a datalog from another car that utilizes the ktuned vss converter and see if they also always get the 158mph reading on the ecu. seems like once the car begins to roll the rpm drop doesnt happen until that vss signal is seen. i could be wrong about that having to do something with it though.

RESOLVED:

first and foremost thank you spunkster for all the help!

secondly what i found was that the vss converter input wire that i had wired into the input going to the engine side of the harness into the vss sensor itself had a double crimp i wasnt aware of leading to a backfeed in the wire going back to the ecu thus causing the rpm drop issue!