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I know this is my first post, this is my attempt to fix my ongoing problems with my USD s13 240sx Rb20det swap

1990 240sx, Rb20det, rb25 turbo 11psi wastegate pressure, sard afpr, sidemount, straightpipe, AEM UEGO, safc-2(Only for Rpm),everything else is stock unknown mileage, ive put 2k on the motor since the swap ran fantastic up until about a week ago it started overboost on wastegate pressure to around 18psi but had good afrs but still backed out as soon as i seen it spike well that stopped and now its lean all the time unless its cold when its cold its like 13.5 at idle and as it warms up it leans out to 15+ all the way to 17.9s. now even at WOT 13.5 is as low as it goes and thats not getting full boost at 5psi i let out any advise or pointer would be great im not asking for someone to tell me what the problem is but mere help me get on the right path, it free revs great, pops after a few hard throttles, Ive litteraly had to plug up safc-2 and at 20% at 800-1000 to get it to idle around 13.7.. The AFR do change at WOT but not much cruising is 15.0-16 spiking around as soon as a WOT 14-13.5 and i let out. Im thinking my Fuel pump is going out as it has been in the car for 2 years, its not a walbro its a Circuit sport 255lph

Problem: Lean , Slight Misfire all through out power range under no load, dont notice it under a load

Things ive checked:

Plugs (.28)gap (white tips)

Vaccum leaks found 1 didnt help

Fuel pressure 40psi with vacc (my attempt to richen it up Sard AFPR also tried factory FPR)

TPS .45 closed 4.10 WOT

Boost leaks none held 16psi didnt leak down

Maf have not checked voltage but have swap mafs no change

Moving wiring no change in idle or afrs

CTS is 2.0 ohms cold

all Injectors are pulsing via noid light

Cleaned up grounds

Checked Codes 54,34, was all that came up auto signal and knock sensor which only comes on when WOT trans hits firewall just alittle near starter

Also was told that rb20 Coolant temp sensor superseeded 4 times to a 03 350z CTS anyone else heard of this? I work for a Nissan Dealership and that is what i got parts to dig up. please any help would be appreciated feel free to email also @ [email protected]

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replaced my 02 sensor and idle is alot better afrs, 14.7-15.5 trys to stay around 15... also noticed that if i wiggled my TPS it would try and stall and from what ive gather from the r32 fsm that indicates a bad tps sensor so im going to pick one up from Raw Brokerage and give that a try... there is also a notice hesiation/bog before boost at low rpm then around 3200rpm it feels as if timing is advanced and pulls good, Revs under no load great and coming out of the gas is fine no stalling...

Fuel pressure @ idle should be around 2.5 kg/cm2 (35.6 psi), @ idle with vacc removed 3.0 kg/cm2 (42.7 psi).

Lean @ idle is not a problem. Lean @ no load is not really a problem. Lean @ boost is a definite no-no.

ECU ignores O2 @ idle.

What is a .28 spark gap (mm, thou)? Do you mean 28 thou (0.71mm)? Then you should open it out to around 35 thou (0.9mm). Do you have the correct heat range plugs (NGK 6s)?

CTS - cold = 2.5kohm, hot = 0.3kohm.

How have you set (programmed) the SAFC? dyno?

Are the injectors clean and flowing correctly?

Have you driven the car with the fuel pressure gauge attached?

Thats were i have my Sard AFPR set at right now alittle higher then 35 i have it set at 38psi and 44psi with no vac i have OEM fpr, and cheap ebay one and my sard and have tried all 3 still same issue, not really worried about the AFRs now ass they are not that bad cruising or dropping down wot.. Spark plugs are Ngk 6's and yes 28mm. it appears that coming of a stop light with out blimping the throttle to take off it leans out 17.0 afrs bogs/Hesitates then right at 3200 rpm boost kicks in and it will take off enough that im spinning my 18x9.5's with a wielded diff. im going to be replacing the throttle postion sensor in hopes that my problem is the Closed and WOT contact points on the TPS. you think this could be my problem?

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