Boost & Idle issue... - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

***dorkidori_s13*** · 05-21-2012, 01:14 AM

hi all. thought id post about a few issues im having. please read before commenting

here are my engine specs:
Blacktop (NOT notchtop) SR20det
T28 S15 turbo (which JUST replaced a worn out T25)
Walbro fuel pump
Greddy FMIC
HKS SSQV 3 BOV (authentic, purchased from MVP Motorpsorts)
Greddy PE2 catback
Megan 02 housing and downpipe
7 psi boost (stock boost)
Stock SR turbo manifold (replaced a Megan tubular manifold).

Boost: so as of late, my car seems to be reaching boost kinda late. my car would shrug a bit right before boost hit, but full boost hasnt been hitting until 4000rpms (all 7psi). From what I remember with stock boost, it should be full spool by 3000rpms. I just installed an S15 specR turbo and OEM manifold on saturday. the car has stopped shrugging before boost, but boost still comes on around 4000rpms. I tightened all my clamps and made sure i wasnt leaking boost (used a boost leak tested we made at the shop), no hissing, no leaky pipes. last i remember, an S15 turbo should be at 7psi around 2800rpms due to being dual ball bearing.

Idle: my SR has never had a consistent idle. sometimes it will idle around 800rpms, other times around 1100. a lot of times it will idle around 1100 then drop down to 800-700 range (i backed off the IACV to push the RPMs up around 1000 at idle). even with the new turbo, car still has idle issues. im thinking i might need to clean the IACV out (a lot of FWD SR guys have to do this, especially with bad turbos) or my TPS is going bad.

the T25 i just pulled off the car was leaking oil pretty badly into the hotpipe (it would spray all over the place with my SSQV). i would go thru at least a quart of oil between oil changes because of it. im taking a guess that excess oil build up would gunge up the IACV pretty badly. but as far as late boost goes, im pretty clueless on this one. one thing i could think of it being is that the fuel pump is going bad (though i dont get any knock, ive burned thru quite a few walbros in the past) which is causing a lean condition before boost or my fuel pressure regulator is taking a dump.

input would be much appreciated...also i am going to restate..

DO NOT TELL ME TO TIGHTEN DOWN MY INTERCOOLER CLAMPS, I BOOST LEAK TESTED THE CAR!!! IT IS NOT LEAKING AIR!!

05-21-2012, 01:14 AM	#1
*dorkidori_s13* ITS LISA'S FAULT!!! Join Date: Jun 2003 Location: Las Vegas Age: 43 Posts: 7,496 Trader Rating: (41) Feedback Score: 41 reviews	Boost & Idle issue... hi all. thought id post about a few issues im having. please read before commenting here are my engine specs: Blacktop (NOT notchtop) SR20det T28 S15 turbo (which JUST replaced a worn out T25) Walbro fuel pump Greddy FMIC HKS SSQV 3 BOV (authentic, purchased from MVP Motorpsorts) Greddy PE2 catback Megan 02 housing and downpipe 7 psi boost (stock boost) Stock SR turbo manifold (replaced a Megan tubular manifold). Boost: so as of late, my car seems to be reaching boost kinda late. my car would shrug a bit right before boost hit, but full boost hasnt been hitting until 4000rpms (all 7psi). From what I remember with stock boost, it should be full spool by 3000rpms. I just installed an S15 specR turbo and OEM manifold on saturday. the car has stopped shrugging before boost, but boost still comes on around 4000rpms. I tightened all my clamps and made sure i wasnt leaking boost (used a boost leak tested we made at the shop), no hissing, no leaky pipes. last i remember, an S15 turbo should be at 7psi around 2800rpms due to being dual ball bearing. Idle: my SR has never had a consistent idle. sometimes it will idle around 800rpms, other times around 1100. a lot of times it will idle around 1100 then drop down to 800-700 range (i backed off the IACV to push the RPMs up around 1000 at idle). even with the new turbo, car still has idle issues. im thinking i might need to clean the IACV out (a lot of FWD SR guys have to do this, especially with bad turbos) or my TPS is going bad. the T25 i just pulled off the car was leaking oil pretty badly into the hotpipe (it would spray all over the place with my SSQV). i would go thru at least a quart of oil between oil changes because of it. im taking a guess that excess oil build up would gunge up the IACV pretty badly. but as far as late boost goes, im pretty clueless on this one. one thing i could think of it being is that the fuel pump is going bad (though i dont get any knock, ive burned thru quite a few walbros in the past) which is causing a lean condition before boost or my fuel pressure regulator is taking a dump. input would be much appreciated...also i am going to restate.. DO NOT TELL ME TO TIGHTEN DOWN MY INTERCOOLER CLAMPS, I BOOST LEAK TESTED THE CAR!!! IT IS NOT LEAKING AIR!! __________________ Check out my IG for what I'm up to! DORKIDORI INSTAGRAM!!!