Why am I running LEAN

[jdmae86]

I'm really stumped... My RB is running lean and I can't figure it out.

I have done the following...

-Running the base map that came on my Pwr FC... I had a good tune but reset the pwr fc b.c of lean issue.-Replaced my fuel filter... 300zx-Checked the Voltage at the fuel pump... 14v's constant-Replaced the fuel pump b.c the one I had was borrowed... Denso Supra TT :]-Replaced my injectors with Nismo 555cc Injectors I had laying around-Replaced the sensor on my wideband-Tested my wideband in my friends car-Tested different Fuel Pressures from 38-45lbs BASE... When I raised the FP it ran leaner wtf?-Replaced my Adjustable FRP with my stock regulator & switched out the fuel rail... no change-Made the map on my Pwr fc STUPID rich with no change...

I dunno what else I can try... I'm going to try a different z32 MAF tomorrow but the car pulls like normal so I don't think its the MAF.

Any Suggestions?

[Carl H]

possibly dead maf, maf can still read voltage but not flow... its odd but i can happen.could also be the pfc, i was poking at a car that no matter what we did when the pfc was set to z32 maf it would run stupid rich regardless of load.same maf in question runs fine on stock ecu w nistune.

[eh?]

Exhaust leak.

[jdmae86]

I have checked for a exhaust leak... I can't find any

It might be the pwr fc but I called apexi today & its a 3 month turn around time for them to test/fix it if something is wrong. I just want to make sure I check everything before my car goes down for 3 months :[

I wish I had a OEM rb25 ecu to see what the a/f's are. Maybe when I try out another z32 maf tomorrow I will be happy...

[kpodj61240]

i had a similar prob one of my intercooler pipes blew off but it was weird because it boosted fine and didnt try to kill the motor or affect performance. but the a/fs were way off.

[WhatsADSM]

I almost wonder if there is a clog or something somewhere in the fuel line.

When you mean lean you mean lean at WOT or all the time?

[240z4u]

^ reminds me, do you have your boost reference vac line connected to your fuel pressure regulator?

[virus77]

Leak in the intake pipe? maybe its getting unmetered air

[Sil240]

Have you checked your seals when you changed your injectors.

Maybe you have a vac leak at the seals?????

[jdmae86]

I have a greddy intake... FRP, BOV, & Boost gauge have there own nipples...

I have checked the injectors... I have ran both 370's & 550's with the same results.

my car idles at 15-16...on throttle in boost it read 15 to off the chart lean... going down the highway in 5th gear its off the chart lean...

[240z4u]

The question is, is your fuel pressure regulator working properly. Maybe T a gauge into the line and tape it to the windshield.

[jdmae86]

I have a SARD FPR & OEM FPR... I have tried both with the same results...

[silviasgp06]

take a nice high resolution pic of your engine bay.

whats are your results wgen you turn of the O2 sensor correction (or what ever its called?)

[240z4u]

Say theoretically you had your fuel lines backwards. Order of fuel system is fuel pump, rail, regulator, return. Your gauge would show you having full fuel pressure if the regulator was installed before the rail but would cause a massive lean situation.

I know it sounds dumb, just throwing that out there.

Evan

EDIT; I have a spare S2 ecu Ill set you up with cheap. They are great to have around for troubleshooting, but my setup is so far from stock its not useful for me to keep anymore.

[maryjane]

very possible!

[jdmae86]

turned out to be AEM wb
Modified by jdmae86 at 1:41 PM 12/7/2009

[240z4u]

Ah okay, I didn't know the car was running fine before!