Hondata

I've been working on getting my tune dialed in on my car after making some hardware changes, and left idle for last, but something weird is happening that I can't figure out.

The setup is:
K20Z3 with DC2.2 cams
KPro V4 with version 4.5.9.0

MAP is about 6-7kpa higher than expected (47kpa actual) whenever the car is idling after startup (or after uploading a tune with the engine running). If I make a change in live tuning, any change at all, MAP stabilizes at a steady 40kpa and my map is respected - so things stabilize. Before then, MAP is higher and fueling correspondingly erratic. In the attached log, screenshot depicting the point, I applied a 1% change in live tuning to a few cells right before 0:31...then everything got better. I can recreate it at will again and again, and nothing I save to the map seems to help it I've tried 2 IACVs, both known to be working, and the issue happens with both. Can anyone guess what this is? I'm lost on it, but I don't want to run without an IACV. I don't see any apparent settings that would cause this. If I reduce the IACV duty cycle, it won't improve...even if I go so low that the car won't idle anymore. In closed loop, short term fuel trims kind of sort this out, by adding the required 12% extra fuel to make up for the air, but I don't want the extra air in the first place...

--Matt

Small typo above. The stable map value that is achieved after making a change to the 0° map with live tuning is 43kpa. Prior, it is unstable and 46-47kpa.

I don't have an ociliscope handy to look at the activity on the IACV, but it is the only thing other than the PCV that lets anything in behind the throttle. Brakes are manual and all accessory ports on the manifold are plugged.

With no physical change whatsoever, this happens...reliably every time...with more than one idle air control valve. TPS calibration is correct, there are no vac leaks, and the AFR is right on the money when this isn't happening.

I saw some old posts suggesting that older versions of KPro had issues where having live tuning on at all prevented saving of the tables that were enabled, so I shut that off and it seemed to make the numbers make sense but idle was awful with both valves regardless of IACV duty cycle. I cleaned one thoroughly and reinstalled it and nothing improved.

I eventually blocked off the valve and set idle to the point where the ECU didn't have to add any timing for it to hold a stable idle and it seems consistent now. I have to make some more adjustments to the 0° table, it seems, but the results at least reflect the numbers now.

I have no idea what was happening with live tuning tables, but I guess I'll avoid them. It seems unbelievable that both IACVs I have, which have no history of trouble, could be at faulty but that's the conclusion for now I guess.

--Matt

Something has to be wrong in my tune somehow. I went to correct the 0° fuel problem and nothing I do makes the fueling change. It's always wrong by the same amount unless I change it with live tuning.

🤦 Maybe I need to start with a fresh file and copy my tables over to it or something. This doesn't make any sense.

Yeah, that did it. I have no idea what the heck went wrong with the old map, but a new copy with every table/parameter pulled in seems to be running fine so far.

The 0 degree map does exactly what the table tells it to now... What an incredibly frustrating thing to ever have happen.

Man this stinks, the 0° problem is back again 🤦

All I did was re enable the IACV and it's back to using some 0° map that isn't mine!🤢

I guess I'll try to do the same thing again but this is ultra lame!

Sorry, for the sake of accuracy I should be more clear. I did exactly these steps:

1) enabled the IACV
2) started the car
3) noticed the idle fuel was 5% high
4) enabled live tuning on 0° and clicked the live box
5) used Ctrl+d 5 times, found perfect idle lambda
6) unchecked the live box and turned off live tuning (noticed 20° was also selected even though I didn't turn it on)
7) saved the map
8) uploaded the map

--Matt