Hondata

Good evening Hondata.

I have a 2018 FK8 with 18k miles. It's been mine since brand new. Professionally tuned by a great friend of mine and well-known tuner.

We have run out of ideas to figure out the issue I am experiencing.

Applicable mods:

PRL intercooler
PRL piping
RV6 ... exhaust and front pipe
Muffler delete
Brand new OEM plugs at OEM gap

Various intakes being tested

Car has been boost leak tested 4 times, bpv tested, evap tested, pcv tested, comp tested, MAF cleaned, tons and tons of data logs when cruising, idling, wot.

Issue:

The car will hunt AFR in closed loop at cruise/low throttle with stock map, hondata map, and Dyno tune. It will hunt some in completely stock intake and stock filter, more on PRL stage 1, and lose its mind with the PRL hvi with race MAF. At wot, it doesn't "hunt", but move around a bit. At low throttle (12-13%) in 6th, the data logs look like an earthquake with parkinson's when the hv with race MAF and scale is installed and look like a mountain range with PRL stage 1 setup and cal.

The hunting is problematic because the car has a slight hesitation feeling while cruising, and just feels like it's slightly "off" while the AFR cycles from 14.0-15.3, up and down, endlessly for as long as the car is NOT at wot. The hunting/oscilation rate slows at idle, and is worst in 6th, cruising on the hwy with the hvi, but still bad/problematic with the stage 1 intake.

I have run wide open exhaust, all intake variations, made sure all clamps are obviously tight (not mechanical noob by a long shot), and as stated, my tuner has gone above and beyond in trying to help me with this for MONTHS at no charge.

I want to see if anyone can help me out so I can do more legwork on resolving this issue instead of pestering him further as he is out of things to try as well.

I can upload logs and cals, but keep in mind, this all happens whether it's a stock map with hvi intake and hvi scale, or full tuned map with OEM intake and drop in filter.

Please let me know what I can do to help aid in your e-diagnostics!

Please post a datalog and the corresponding calibration.

Here is 1 datalog and corresponding cal

This is dyno tune with PRL stage 1 intake

Stock map with dp and HVI race maf scale

The AFM, trims and INJ are steady yet the lambda is changing. It could be the o2 sensor and/or o2 sensor wiring.

Hondata wrote: Tue Feb 08, 2022 9:01 am The AFM, trims and INJ are steady yet the lambda is changing. It's the o2 sensor and/or o2 sensor wiring.

Finding a replacement in stock has been outrageous... But supposedly I have one on the way. I will 100% update the thread when I get the replacement LAF.

Thank you for your insight; I'm hoping this solves it.

@hondata Well... put in the brand new OEM Honda primary sensor and it made zero difference. See logs from fresh flash and same stage 2 tune as before. Just as stumped as before.

Never ran anything but 93. not many mods as listed above.

This is a pic of:
(top) Hondata DP basemap with drop-in filter
(middle) stage 2 dyno tune with drop-in filter
(bottom) PRL HVI RACE MAF Stage 2 tune

Nothing changed mechanically in any way except for the RACE maf intake in the bottom pic. All within a days of eachother.

Seems like you have narrowed it down then. Can you provide datalogs for the above screen shots?

Hondata wrote: Tue Feb 15, 2022 11:52 am Seems like you have narrowed it down then. Can you provide datalogs for the above screen shots?

Those are just additional files recorded when I recorded the logs already posted above. All the calibrations listed. I took so many over the last 4-5 months.

Tuner and I are out of options besides return to stock and sell the car.

Hondata wrote: Tue Feb 15, 2022 11:52 am Seems like you have narrowed it down then. Can you provide datalogs for the above screen shots?

Data logs and cal from today. Same stg 2 cal from above.

Wondering if a slightly askew oem maf could cause the constant oscillation that just gets worse with more airflow (PRL HVI RaceMaf)?

Attached graph shows a scatter-plot of exact data points pulled from the Oscillating cruise datalog I posted today. As you can see, the maf is mixing gal/s and afmv all over the place just in the 3 volt ranges I measured. Is this how the OEM maf works? Or is mine faulty from the factory?

This is from the 60mph cruise datalog, zoomed in. Compared to a stock datalog the range of the lambda, cylinder charge and fuel injector is about the same. Sorry, could not find a stock datalog with a nice steady cruise.