Rb20 backfires on decel then applying throttle

[DVS JEZ]

Just tuned a r32 rb20. Only problem now is on the freeway in 5th gear when applying slight throttle after decel. There is a loud POP/backfire.
Has anyone encountered this and how did u fix it?
Thanks
Jez

[Matt]

What do your logs say with the AFRs and injection pulsewidth vs AFM voltage?

If the AFM voltage is spiking and causing AFRs to go rich on re-acceleration then its a mechanical issue

[bachig24u]

a lazy workaround: increasing fuel cut 50 or 100 rpm can help cover the issue. just don't get too wild as it also causes bucking behaviour if set too close to cruise rpms.

if the fault is electronic Calibration:
Sounds more like Tip in scales is the problem,
if 'k-constant' , MAF, Injectors or even fuel pressure is different from OEM then maybe focusing on Acceleration Enrichment (tip-in) correction will sort the fuelling problem out.
Often the AE tables are over looked as it's very challenging to get logs that reflect accurately whats going on.. thats where the calculations come in to tuning the scales correctly.

mechanically: Check the Fuel pressure regulator isn't leaking fuel in to the inlet manifold.
nothing else comes to mind.

[louiswun]

My A31 with RB20DET is fully standard included the ECU and rom file inside, it always do that....for years !

[bachig24u]

louiswun,
Does your car have a larger exhaust system from dump pipe back?

[louiswun]

Fujitsubo 76mm cat back, stock exhause manifold, stock turbo, stock dump pipe and stock front pipe.