FN2 won't work with any MAF calibration (running extremely lean)

FlashPro questions & answers specific to the FN2 European Civic Type R
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rattinger
Posts: 4
Joined: Thu Sep 11, 2014 11:46 am

FN2 won't work with any MAF calibration (running extremely lean)

Post by rattinger »

Hello!

Here is the problem:

Car is 2010 CW Civic Type R with following modifications:
- custom made 4-2-1 header
- 2.5" exhaust with no cat (secondary O2 sensor removed also)
- RRC intake with stock air box K&N installed

Car was tuned with MAP Calibration on dyno making ~225 hp.

Car worked pretty fine, but fuel consumption was quite high and it didn't work very fine on part throttle (thoughts based on "Ass-dyno" and engine sounds).

Problem is: now i'm trying to return to MAF-calibrations (which should be used instead of map-calibrations), but car won't work at all with any MAF-calibration.

Right after start S.term starts to rise until reaches 47% and A/F goes up to 18-20 ! In other words, car is running very very lean.

If I touch to throttle pedal, car dies immediately.

I have already tried new stock wideband O2-sensor, new MAF-sensor and many different MAF-baset calibrations, including N Group Reflash.

I think that it can't be air leak, because it works with MAP-calibrations?

I haven't yet tried to unlock ECU and returning it to stock.

Also if it would matter, I also mention that tried once also Asian version FD2 map (made fault codes)

(sorry for bad language, hope you understand :)
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Spunkster
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Posts: 23878
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by Spunkster »

Try returning the ECU to stock, but do not unlock it and see if it will run with that.
rattinger
Posts: 4
Joined: Thu Sep 11, 2014 11:46 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by rattinger »

Thanks for reply

I've already tried that
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Spunkster
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Posts: 23878
Joined: Fri Sep 20, 2002 5:06 pm
Location: Hondata

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by Spunkster »

If it does not run with the return to stock then there is some issue with the vehicle that needs to be addressed.
rattinger
Posts: 4
Joined: Thu Sep 11, 2014 11:46 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by rattinger »

When using MAF-calibrations I get following values on idle:

Cold engine:
RPM 1300rpm
MAP 410 mBar
AFM.v 1,33 V
AFM 4,3 g/s
AFC.c 100 mg
S.Trim 47%
A/F 19,20

Even when engine not running AFM values are:
AFM.v 0,76 - 0,84
AFM 0,57 - 0,82 g/s
AFM.c 0 mg

Are those values correct?
rattinger
Posts: 4
Joined: Thu Sep 11, 2014 11:46 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by rattinger »

Any advice? Anybody?
tctc
Posts: 7
Joined: Thu Jun 09, 2016 3:17 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by tctc »

rattinger wrote: Sun Oct 07, 2018 12:26 am Hello!

Here is the problem:

Car is 2010 CW Civic Type R with following modifications:
- custom made 4-2-1 header
- 2.5" exhaust with no cat (secondary O2 sensor removed also)
- RRC intake with stock air box K&N installed

Car was tuned with MAP Calibration on dyno making ~225 hp.

Car worked pretty fine, but fuel consumption was quite high and it didn't work very fine on part throttle (thoughts based on "Ass-dyno" and engine sounds).

Problem is: now i'm trying to return to MAF-calibrations (which should be used instead of map-calibrations), but car won't work at all with any MAF-calibration.

Right after start S.term starts to rise until reaches 47% and A/F goes up to 18-20 ! In other words, car is running very very lean.

If I touch to throttle pedal, car dies immediately.

I have already tried new stock wideband O2-sensor, new MAF-sensor and many different MAF-baset calibrations, including N Group Reflash.

I think that it can't be air leak, because it works with MAP-calibrations?

I haven't yet tried to unlock ECU and returning it to stock.

Also if it would matter, I also mention that tried once also Asian version FD2 map (made fault codes)

(sorry for bad language, hope you understand :)
Hi, were you able to fix this? I have the same problem. Return to stock doesn't help.
tctc
Posts: 7
Joined: Thu Jun 09, 2016 3:17 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by tctc »

Spunkster wrote: Tue Oct 09, 2018 9:09 am If it does not run with the return to stock then there is some issue with the vehicle that needs to be addressed.
Factory reset doesn't work either. I tried disconnecting the battery for a while - no result. Short-term correction of about 30% and sluggish response to the pedal. How to reset the factory firmware?
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Spunkster
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Location: Hondata

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by Spunkster »

To return to stock, go to the online menu and click on return to stock.
tctc
Posts: 7
Joined: Thu Jun 09, 2016 3:17 am

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by tctc »

Spunkster wrote: Thu May 15, 2025 9:06 am To return to stock, go to the online menu and click on return to stock.
I did this, the result is the same as I described above.
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Spunkster
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Location: Hondata

Re: FN2 won't work with any MAF calibration (running extremely lean)

Post by Spunkster »

Then there appears to be a mechanical or wiring related issue with your vehicle.
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