E36 m52 Turbo RK tunes Lean on Boost ( help )

[m52dinan]

My set up it's an m52 stock internals with spacer , HG, Arp head studs, m50 mani and m3 cams . 6266 , rapid spool mani , 80lb injectors, hpx maf with RK tuning.
I purchased the ECU used and it's running ok, idle it's a little skipy but still in 14.3 to 15.3 afr , my biggest issue it's on full boost 16-17 psi it's getting lean , 12.5 to even low 13
How is that possible with 80lb injectors?

[JPE36M3]

how much fuel pressure do you have with vacuum not attached?

[Kevin325i]

Spark plug gap and what part number are you using?

Condition of coils and boots? Are they 150k mile original parts? Shitty aftermarket ones?

What fuel pump and have you replaced the factory wiring to the pump with a second relay and larger wire?

[328iFun]

I've had leaks before the maf, at the maf, and after - at the manifold.

All of which made the afrs sit in low or high 12's.

After fixing the leaks afrs are in 11s

Did you do a boost leak test ? What psi? 15+ at idle usually indicates a vacuum leak which would turn into a boost leak



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[328iFun]

Ngk 4091 gapped to 22
Original coils with about 260 km on them
Wallbro 255 but didn't replace any wire

- - - Updated - - -

Didn't do a boost leak , but I will soon
It's getting into 12, even low 13s after 10psi aroind 16

Yeah should do a boost leak test before you do anything else...

The intake manifold may be seeing 10 briefly but bleeding off due to a leak. I've been boost leak testing maybe twice a month and usually always find one somewhere. If you need a tester butters makes/sells them. However, I've never seen anywhere near 16 AFR @ 10 psi.

Fuel pump should also run of its own wiring / relay. You can use the stock + to trigger the relay and then run a thicker gauge wire to power the relay and the fuel pump. Using a thicker gauge wire doesn't hurt