Reasons A Stock Rb25det Would Run Rich:

[R33 Jared]

Ayo,

Full acceleration, anywhere over 3.5k revs causes my afr to completely overfuel itself. (I have searched many other threads but I feel mine is slightly different). Applying only 75% throttle however it accelerates great and smooth. What are some culprits I can address to try and smooth out this AFR under full load? I have brought my RB25 back to absolutely 100% stock everything, no aftermarket BOV, stock SMIC, stock turbo setup, stock Airbox, everything is stock. Still running a 2.5" exhaust as my partner and I enjoy communicating whilst driving.

I have just purchased:

- a new ignition loom (wiringspecialties)

- NGK Copper BPR6 1.1mm gap plugs

Other than those two obvious ones, the possibilities then open up a whole new branch of things. Fuel Pressure? Coilpacks? Leaking BOV? Would a leaking BOV be capable of throwing off an AFR that much!? Please, I'm sure a lot have been through this. I'm able to upload a video if that may help.

[Ben C34]

Boost leak. Do a pressure test to find it.

Close the gap on the plugs down to 0.6

[KiwiRS4T]

I take it you have installed a wideband afr meter? All RBs seem to run rich - I don't know if yours is worse than average. Check for boost leak like Ben says and maybe clean your AFM.

[89CAL]

Give the AFR's you are see seeing and under which conditions. It may not be rich

The only 2 things that cause over fueling are too much fuel or not enough air

What causes that will be the bigger question. Tune, losing air out of the system post AFM, 1 or more dud injectors

More info needed

[R33 Jared]

Boost leak. Do a pressure test to find it.

Close the gap on the plugs down to 0.6

Will run a pressure test in the morning. It always seemed to run rich, but it one day seemed really bad. Closing the gap will what? Help combustion even when there is an incopious amount of fuel spraying in? If this solves the issue is it unsafe to leave it at 0.6?

[blind_elk]

The need to shut down the gap on a spark plug (in a stock engine) is generally indicative of a poor spark (coil). Try a new set of either factory or Splitfire coilpacks.

The spark plug heat range for a stock 33 is a 5, so try a set of BP5nnn plugs, 1 - 1.1 gap.

Get the injectors cleaned.

Edited June 11, 2016 by blind_elk

[R33 Jared]

Try a new set of either factory or Splitfire coilpacks.

Thanks for suggestion, I was already thinking of heading down this path but wanted some reinforcement before I paid the $700 bucks (again). On my S2 motor I had Splitires but they don't mate with my S1 (as everyone knows).