running extremely lean

[Emperor_Tha]

s13 black top,stock t25, 370 cc injectors and maf3 inch exhaust with high flow cat.fmic, recirculated greddy rs bov 300zx fuel filter, walboro 255 fuel pump, stock fpr7psi no boost contoller i had an autometer narrow band before. a/f read good. lean at idle, stoich at cruising, and rich at wot.

a week before my megan racing fpr stop working so i switch back to stock. car ran good.

then lately my car been reading lean at wot, so i switch to an autometer wide band. my car idle at 16, cruise 14.2-15.4, and 16 at wot. bog really bad about above 4500 rmp.

i did fuel injetion cleaning service at work and add gas cleaner to the tank. did not help. then i pinch off the return hose with a vise grip. still no good. then i drove with the maf unplug. idle 14.6, cruise 12.1-13.6 wot is 10.9-11.2. this is before 2500 rmp. 1st-5th gear.

then i swap over my sohc maf. my car idle at 16, cruise 14.2-15.4, and 16 at wot.

i clean all connector with cleaner.

what else should i look at.

[Emperor_Tha]

bump?

[Emperor_Tha]

ok got it narrow down to the walboro fuel pump.

i was told that people been seeing walboro fuel going back lately.

is the 300zx fuel pump worth getting for its price?

[esahuque]

what happened to the fuel pump? how did you know?

the reason i'm asking is because i just blew my motor because i ran to lean and before i rebuild i'm trying to fine the problem.

[Emperor_Tha]

i clean all my injectors, clean fuel rail, put new filter, clean fuel line, did fuel injection service. clean out pump filter.

temp sensor tested good. no vaccumm leak or boost (7psi no boost controller) swap ecu. swap maf

test fuel pressure at idle, regulator working fine. fuel pressure is fine when reving on no load.

only thing left is the fuel pump is crapping under a load.

dont have a long enough fuel line to see the pressure while driving.