Running Lean with a loss of power??

[jcquick]

I have a S13 Blacktop in a 96 S14 with a bunch of mods, Engine related such as: Apexi intake w/ Ejuku Racing Intake Pipe, Greddy Intercooler, Recirc. BOV, Profec B Spec II Boost Controller, Turbo Elbow and Downpipe with a 3" Exhaust, Megan Exhaust Manifold, Walbro Fuel Pump, Nismo Adjustable FPR w/ gauge, custom oil cooler w/ remote filter.

This is my first turbocharged vehicle, I've never dealt with this type of problem. I would like to thank all you guys for all your help, since this website is where I've learned all that I know about the SR20DET/240SX.

The problem I'm having is when I'm cruising around or during the vacuum to boost transition. When I'm going at a steady speed (i.e. 50, 70 mph) or when I slowly accelerate and begin boost with a reading of 1-2 psi, my Wideband intially reads 14.6-14.8 A/F but then it feels as if there is a loss of power and it begins to read lean 15.8-16.0 A/F. I figure this occurs at a certain position of the throttle (25-35% in reference to WOT) because when I let off just a bit the A/F goes back to normal and it feels like I regained the power. I thought the engine was starving fuel so I installed the fuel pump and Adjustable FPR with a idle of 42psi (vacuum line connected) and the problem still continues. Any suggestions??

Additional Info: I don't have any leaning out issues under hard acceleration or full boost. Also, my boost controller isn't the issue since I've been having this problem even before I installed the Profec B. Full Boost is at 11-12psi with a reading of 12.3-12.8 A/F. Also, when I change out my plugs every oil change they appear white (lean).

[Emperor_Tha]

I had a problem mainly in 4th and 5th gear about 1k to2k rpm where it leans out 16.0+ around 25%+ throttle. Feels like no power , bog a little and u can already hear the t25 spool. all I did was just retune safc. Ajusted the throttle point and fuel curve

What u can do is clean your maf and check if the o2 sensor is working properly.

[jcquick]

Emperor - you know exactly what I'm talking about. I can hear the turbo spooling up and it feels like there is a 25% loss of power with little bogging. Except my issues occur from 2k-3k. Well I don't have a S-AFC or any kind of aftermarket management, so I won't be able to tune. I recently installed a new o2 sensor with the Greddy Elbow. I will do as you suggest by cleaning the MAF sensor, but how exactly do you clean the MAF. I clean my Apexi air filter frequently and rarely have any dirt in the intake. Do you just blow some compressed air and brush the dust out?

[IanS]

Have you checked for ECU codes, sounds like your knock sensor is on the fritz.

[Emperor_Tha]

maf cleaner sprayElectrical cleaner spray