car wont build boost over stock psi! :( - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

anfitch2k5 · 02-25-2010, 07:04 PM

i just had my ecu tuned from enthalpy, no bad words for them. everything went smooth, heres my problem. tuned for s13 black top 740 cc inj, s15 turbo, fmic, exhaust, intake, z32 maf and a isis intake manifold. when i got the ecu back i put it in the car but the car had yet to have the intake manifold on it, i was running the stock manifold still but it still pulled great and put down 278hp on 18psi. i finally got the intake manifold on with all new gaskets, install went flawless no problems at all. at first it kinda sputtered under boost, afr gauge still said i was below 11.0 so i changed the plugs, re gapped, same thing. messed with the fuel regulator, nothing changed, adjusted the timing both retard and advanced, nothing changed. im just stuck with possibilities. i got in to drive it today after checkin for boost leaks and now all of a sudden it doesn build boost anything over then stock. just falls on its face after 7psi. i can run 7psi smooth but its slow as dirt ya know? lol could it be a wastegate problem? something else i can look into? it seems like the intake manifold was bringing in more air ofcourse but enough to blow out spark when plugs are new and regapped to .028? could it be ignition coils?
any help or info would be greatly apprechiated. i searched online and everything kept coming up spark plugs.
thanks alot in advanced!

bikrman2 · 03-01-2010, 08:07 PM

Check for vacuum leaks..... A rolled injector o-ring, pinched/ leaking vacuum line etc..

anfitch2k5 · 03-15-2010, 08:33 PM

well i found a boost leak but its still runnin weird. it pulls smooth but around 4000 rpms it hiccups still, and again 5000 rpms so i let out of it. its like, not enough air, my AFR gauge is pegged below 11.0. im thinkin its leakin at a gasket. so i guess ill order all new ones and do it all over again.
any other ideas guys?!

s14unimog · 03-16-2010, 10:13 AM

pressure test the boost system. Literately make a tester, pull your MAF and run up the pressure. I had tons of leaks at the runners of my intake manifold. I used a gasket tack to seal it.

02-25-2010, 07:04 PM	#1
anfitch2k5 Zilvia Member Join Date: Sep 2009 Location: austin, tx Age: 34 Posts: 256 Trader Rating: (5) Feedback Score: 5 reviews	car wont build boost over stock psi! :( i just had my ecu tuned from enthalpy, no bad words for them. everything went smooth, heres my problem. tuned for s13 black top 740 cc inj, s15 turbo, fmic, exhaust, intake, z32 maf and a isis intake manifold. when i got the ecu back i put it in the car but the car had yet to have the intake manifold on it, i was running the stock manifold still but it still pulled great and put down 278hp on 18psi. i finally got the intake manifold on with all new gaskets, install went flawless no problems at all. at first it kinda sputtered under boost, afr gauge still said i was below 11.0 so i changed the plugs, re gapped, same thing. messed with the fuel regulator, nothing changed, adjusted the timing both retard and advanced, nothing changed. im just stuck with possibilities. i got in to drive it today after checkin for boost leaks and now all of a sudden it doesn build boost anything over then stock. just falls on its face after 7psi. i can run 7psi smooth but its slow as dirt ya know? lol could it be a wastegate problem? something else i can look into? it seems like the intake manifold was bringing in more air ofcourse but enough to blow out spark when plugs are new and regapped to .028? could it be ignition coils? any help or info would be greatly apprechiated. i searched online and everything kept coming up spark plugs. thanks alot in advanced!

03-16-2010, 10:13 AM	#4
s14unimog Nissanaholic! Join Date: Dec 2003 Location: In a place, near a river, over a lake Age: 34 Posts: 2,415 Trader Rating: (22) Rides Gallery: s14unimog Feedback Score: 22 reviews	pressure test the boost system. Literately make a tester, pull your MAF and run up the pressure. I had tons of leaks at the runners of my intake manifold. I used a gasket tack to seal it. __________________ Fuking ginger bread man stole my wallet... SHIFT*lock_slide to side d3m3rs0n: if i have a baby im naming it Brandons Fault Emerson

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03-01-2010, 08:07 PM	#2
bikrman2 Zilvia Junkie Join Date: Dec 2009 Location: Albany NY Age: 38 Posts: 541 Trader Rating: (4) Feedback Score: 4 reviews	Check for vacuum leaks..... A rolled injector o-ring, pinched/ leaking vacuum line etc..

03-15-2010, 08:33 PM	#3
anfitch2k5 Zilvia Member Join Date: Sep 2009 Location: austin, tx Age: 34 Posts: 256 Trader Rating: (5) Feedback Score: 5 reviews	well i found a boost leak but its still runnin weird. it pulls smooth but around 4000 rpms it hiccups still, and again 5000 rpms so i let out of it. its like, not enough air, my AFR gauge is pegged below 11.0. im thinkin its leakin at a gasket. so i guess ill order all new ones and do it all over again. any other ideas guys?!