Fk8 AFR hunting / oscillation

FK2 Civic Type R 2015-2017, FK8 Civic Type R 2017-2021, FL5 Civic Type R 2023+ and Integra Type S 2024+
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Hondata
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Re: Fk8 AFR hunting / oscillation

Post by Hondata »

The changes you are making are not going to identify anything one way or the other.

When I said to test things one at a time, I meant from a completely stock vehicle change one thing at a time.

It goes back to the two basic approaches - start from a known good position and change one thing at a time until you identify the cause by replicating the behavior, or start from your current position and change things until the behavior returns to normal.
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SpicyRat
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

Problem is, if I go back to stock, that's no hondata. Can't monitor anything. And with the stock intake, you can't feel any surges while cruising. So that's not a viable option for diag to go completely stock.

If you mean stock parts while retaining hondata, I could do that, but what if there's an ECU issue? I'll never know.

Keep in mind, this issue was present before the charge pipes (reason I bought them was to rule out a leak in the OEM rubber). So the only real change was the RV6 downpipe and HVi with race MAF. Race MAF is off now. Stock intake with drop in and PRL silicone tube is on. Leaving a RV6 downpipe and front pipe as the culprit? I checked all mounts on the dp and fp yesterday and all bolts/nuts/gaskets are snug and sealed.

I'd think unplugging a sensor that informs the ECU on pre-tb boost and vac would have some impact if disconnected, no? If not, why even have it?
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

After driving more with the charge pipe sensor unplugged, it limits the throttle when attempting to build boost.

But has no effect on vac state afr or vac regulation.
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

Hondata wrote: Wed Mar 09, 2022 6:28 pm The changes you are making are not going to identify anything one way or the other.

When I said to test things one at a time, I meant from a completely stock vehicle change one thing at a time.

It goes back to the two basic approaches - start from a known good position and change one thing at a time until you identify the cause by replicating the behavior, or start from your current position and change things until the behavior returns to normal.


Do you have the log of the stock fk8 from page 1 in AFR and not lambda to compare apples to apples?
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Re: Fk8 AFR hunting / oscillation

Post by Hondata »

AFM-stock-exp.fpdl
(13.37 MiB) Downloaded 65 times
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

Hondata wrote: Fri Mar 11, 2022 8:56 amAFM-stock.fpdl
File loads blank. Nothing there once downloaded.
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

This is stock 2017 R with downpipe map. Put all stock components back on except for RV6 downpipe and frontpipe. Totally stock intake arm, filter, IC piping, etc.
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Stock data 2.fpdl
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factory_2017-2018_fk8_with_downpipe.fpcal
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Re: Fk8 AFR hunting / oscillation

Post by Hondata »

Standard deviation of lambda (in AFR) when in closed loop:

- 5 minute datalog from my vehicle = 0.10
- 'stock data 2' = 0.24

Now go and unplug the S02 and do the same test, near as you can with regards to temperature / speed / etc.
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

SOLUTION WAS DISCOVERED.

Not a tuning or mechanical issue of any kind.

Will post info by mid-week. 👍
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

The solution that absolutely solved this issue was to clean the ECU terminals of all the transparent/bluish colored siliconized grease that was on there from the factory. there were little tiny bits at the bottom of the ECU pin sections where it looked like those little globs (whatever you want to call them) were touching more than one pin at a time. Likely creating crosscontamination of signals.

I cleaned the ecu with MAF parts cleaner and cue tips.

Reconnected the battery.

Reflashed the HVI Racemaf cal from my tuner.

Reinstalled the race maf HVI yet again.

Started the car, logged data, and today is the 4'th or 5'th day of continuous results. Not a shred of the past mountainous nonsense at all. See attached photo for comparison and note that my tuner and I have gotten the trims to essentially zero at this point and the car is smooth and responsive as can be!!!

So, I don't know if this is a Honda issue or what, but I think it needs to be shared with the FK8 community to check their ecu for excess grease.
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sloth4urluv
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Re: Fk8 AFR hunting / oscillation

Post by sloth4urluv »

Thanks for the information.
Glad you go the issue resolved.

I'm assuming it is more an issue with poor connection than crosstalk. Especially if the sensor is unbuffered changes in the impedance with the connection could change the voltage level read by the ECU.
It is likely that vibrations while driving would cause the voltage to fluctuate.

I'm guessing the grease is there to prevent corrosion on the contacts, so it is probably something you should keep in mind.
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

sloth4urluv wrote: Thu Mar 17, 2022 6:11 am Thanks for the information.
Glad you go the issue resolved.

I'm assuming it is more an issue with poor connection than crosstalk. Especially if the sensor is unbuffered changes in the impedance with the connection could change the voltage level read by the ECU.
It is likely that vibrations while driving would cause the voltage to fluctuate.

I'm guessing the grease is there to prevent corrosion on the contacts, so it is probably something you should keep in mind.
I have had the ecu out before when pinning the difference sensors for connectivity recently, and had the ecu out a while ago when sent to Ktuner to unlock it, initially. So its had chances to reconnect to pins before. The only thing I changed in any way was cleaning the ecu terminals of the excess grease. Whether that grease was impeding the signal on individual pins or mixing electrical signals, it was doing something as removing the stuff on the ECU side solved the nightmare issue completely.

I kept the grease that was down inside of the 2 harness connectors, just removed the stuff in little globs down in the ECU/receiver side of the connection. If the ecu terminals get corroded in 10 years, it is what it is and it's a cheap replacement.

A friend of mine had this issue with a Cadillac not too long ago with excess grease in the ecu that was causing the immobilizer to work sometimes and not others, it would not recognize the fob to unlock the doors, it was this very odd issue the dealer could not solve despite the 3 trips... He pulled the ECU sprayed it down with CRC, blew it out with compressed air, never had the problem ever again over years.
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Re: Fk8 AFR hunting / oscillation

Post by SpicyRat »

3-21-22 update

After the ECU cleaning, the car is still running terrific without any mechanical changes. HVIRACEMAF tuning is complete. Cruise is still super stable (no more mountains at all) and top rpm under full boost is very stable as well. This is my last update to the thread. If anyone wants any additional info or insight, please pm me.
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