SR20DET w/ T25 not boosting - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Tom25666 · 06-16-2009, 07:19 PM

first off: s13 w/ redtop sr, stock t25/actuator, stock smic/bov, sr maf, aftermarket downpipe/ test pipe, walbro 255, ele fan, mostly stock (370cc injectors, no tune), no a/c, no boost gauge/controller

question: it feels like the turbo only spools half the time. or maybe it spools all the time but the boost gets lost along the way. there are no unusual noises (whistling) or smoke anywhere (blue or otherwise) that I can tell. I know the stock bov isn't a SSQV, but are you supposed to be able to hear it at all? Could the BOV be sticking open/closed sometimes? Maybe the actuator sticking? I haven't taken the turbo out to inspect, but I was thinking that if the turbo itself was bad it would be fairly obvious. Its been doing this since I had the SR swap, and I've done all the obvious stuff i.e. filters, belts, plugs. I'm running a Maxima clutch, feels like it is gripping just fine. WTF?

encludemeout · 06-16-2009, 07:31 PM

I don't think it would be your bov

Could be the wastegate staying open though so you aren't able to hold boost

Sileighty_85 · 06-16-2009, 07:43 PM

EDIT: I see you said no boost controller, so you are just running a Vac line to the W/G?

When not running a BC with just the Vac line on the W/G your only running like 4psi, which would explain why you feel like there is no boost

slider2828 · 06-16-2009, 07:45 PM

Check your timing, look for boost leaks... check wastegate (per fsm).

Rapier46 · 06-16-2009, 07:47 PM

Quote:

Originally Posted by Sileighty_85

are you running a boost controller or just putting a vac line straight on the Actuator?

Quote:

Originally Posted by Tom25666

no boost gauge/controller

msglngthfuck

Sileighty_85 · 06-16-2009, 07:51 PM

Quote:

Originally Posted by Rapier46

msglngthfuck

Thanks for helping

I just noticed, go be not so helpful somewhere else

KiLLeR2001 · 06-17-2009, 01:05 AM

Sounds like ignition timing could be too retarded.

DataXUnknown · 06-17-2009, 01:13 AM

check your wastegate and make sure there is a clip holding it on at the end. mine felt like this too and i noticed my wastegate actually fell off because the clip rusted and broke.

waynehead05 · 06-17-2009, 02:53 AM

Why wouldnt it be 7 if the wastegate is a 7psi gate?

DataXUnknown · 06-17-2009, 12:23 PM

^ I don't understand that either. I believe that is only for the KA-T setups, with SR it's 7psi.

burnsauto · 06-17-2009, 12:34 PM

check timing first, then the wastegate, piping leak, etc.

go to advance/autozone/etc and buy a $20 boost gauge... just something to get you by so you know what psi you're running. (put a T fitting between the fuel pressure regulator, and the throttle body vacuum line, and run the boost gauge signal line off that.)

Tom25666 · 06-18-2009, 02:58 PM

Quote:

Originally Posted by DataXUnknown

^ I don't understand that either. I believe that is only for the KA-T setups, with SR it's 7psi.

that's what i was thinking. i appreciate the input everyone. so probably wastegate or timing? if it was vacuum it would feel weak all the time and be audible, yes?

waynehead05 · 06-18-2009, 03:37 PM

one way to check if you're boosting or not is pull the wastegate signal off completely. Start the car and ONLY go down the block and back. Punch it, but don't go past 5k. You'll know if you're boosting or not, cause it should boost upwards of 20 pounds. If it isn't boosting it's not your wastegate.

highlifein909 · 06-07-2012, 05:20 PM

YO! i need some help., recently my car was running fine, nd outa the no where car made a small boom noise from exhuast nd shutted down, i restarted it and after the car wasnt holding boost, after tryin to BOOST it while driving car shut off, car is idling fine but smells rich, no funny or knocking noises, can it be my turbo? wastegate or turbo leak???

sandeezy · 06-11-2012, 10:53 PM

check all your exhaust gaskets most definitely. exhaust leaks = boost leaks and they can throw you off bad.

kikcaffine · 06-12-2012, 06:48 AM

My car did the same thing, the guy grabbed what he thought was a vac source off the cold pipe after the intercooler but before the throttle body (stock SMIC piping), re-routed the lines correctly (stock) and it works fine afterwards. Check to make sure your lines are routed to the correct locations on the throttle body.

steve shadows · 06-13-2012, 12:11 AM

A lot of times people diagnose problems like this and they can't figure out what in the world it is.

It is often the CAS or base timing being off...i.e. you need to get a timing light and an old distributor wire and check your timing per FSM to make sure it's 15 BDTC on the crank so you're all setup right...

Granted this is usually the problem if everything else checks out first.

Another thing is to check the ground wire that goes from the coil pack harness to the back of the head/firewall as well. This usually comes loose and can cause a pretty annoying mis-fire right where you don't want it.

Jesse SR20 · 06-13-2012, 12:28 AM

After you confirm your timing, and grounds, go to home depot and buy the parts to build a boost leak tester (you'll need an air compressor, or a hand pump of some kind). Search google and youtube for what I'm talking about.

You can NOT visually inspect for boost leaks. You'd be amazed at how many leaks the average boosted setup has unless they pressure test it.

06-16-2009, 07:19 PM	#1
Tom25666 Zilvia Addict Join Date: Aug 2008 Location: Alabama Age: 40 Posts: 644 Trader Rating: (5) Feedback Score: 5 reviews	SR20DET w/ T25 not boosting first off: s13 w/ redtop sr, stock t25/actuator, stock smic/bov, sr maf, aftermarket downpipe/ test pipe, walbro 255, ele fan, mostly stock (370cc injectors, no tune), no a/c, no boost gauge/controller question: it feels like the turbo only spools half the time. or maybe it spools all the time but the boost gets lost along the way. there are no unusual noises (whistling) or smoke anywhere (blue or otherwise) that I can tell. I know the stock bov isn't a SSQV, but are you supposed to be able to hear it at all? Could the BOV be sticking open/closed sometimes? Maybe the actuator sticking? I haven't taken the turbo out to inspect, but I was thinking that if the turbo itself was bad it would be fairly obvious. Its been doing this since I had the SR swap, and I've done all the obvious stuff i.e. filters, belts, plugs. I'm running a Maxima clutch, feels like it is gripping just fine. WTF?

06-16-2009, 07:43 PM	#3
Sileighty_85 Post Whore! Join Date: Dec 2006 Location: Misawa, Japan Posts: 6,815 Trader Rating: (8) Feedback Score: 8 reviews	EDIT: I see you said no boost controller, so you are just running a Vac line to the W/G? When not running a BC with just the Vac line on the W/G your only running like 4psi, which would explain why you feel like there is no boost __________________ 後輪駆動車１番 1989 Built SR GT2871R -363whp 1998 S14 W/RB25- 250ish (For Now) 1986 SR86 - 200ish 1990 R32 GTR - 320hp Don't Buy Engines from JDM-Online http://zilvia.net/f/businesses/207457-jdm-online.html Don't Buy XS-Power or SSAC Shit

06-16-2009, 07:45 PM	#4
slider2828 Post Whore! Join Date: Oct 2004 Location: San Francisco, CA Posts: 6,040 Trader Rating: (13) Feedback Score: 13 reviews	Check your timing, look for boost leaks... check wastegate (per fsm). __________________ Turn and Burn!

06-17-2009, 01:05 AM	#7
KiLLeR2001 Post Whore! Join Date: Jun 2007 Location: オーランドフロリダ Posts: 7,955 Trader Rating: (46) Feedback Score: 46 reviews	Sounds like ignition timing could be too retarded. __________________

06-17-2009, 02:53 AM	#9
waynehead05 Zilvia Junkie Join Date: May 2005 Location: Dallas Age: 38 Posts: 466 Trader Rating: (1) Feedback Score: 1 reviews	Why wouldnt it be 7 if the wastegate is a 7psi gate? __________________ Who in their right mind would want to lead this nation of Me-First Right-Now Do Nothings??

06-16-2009, 07:31 PM	#2
encludemeout Zilvia Member Join Date: Jul 2008 Location: Ohio Posts: 224 Trader Rating: (7) Feedback Score: 7 reviews	I don't think it would be your bov Could be the wastegate staying open though so you aren't able to hold boost

06-17-2009, 01:13 AM	#8
DataXUnknown Post Whore! Join Date: Sep 2006 Location: Mission Viejo, CA Age: 35 Posts: 2,934 Trader Rating: (30) Rides Gallery: DataXUnknown Feedback Score: 30 reviews	check your wastegate and make sure there is a clip holding it on at the end. mine felt like this too and i noticed my wastegate actually fell off because the clip rusted and broke.

06-17-2009, 12:23 PM	#10
DataXUnknown Post Whore! Join Date: Sep 2006 Location: Mission Viejo, CA Age: 35 Posts: 2,934 Trader Rating: (30) Rides Gallery: DataXUnknown Feedback Score: 30 reviews	^ I don't understand that either. I believe that is only for the KA-T setups, with SR it's 7psi.

06-17-2009, 12:34 PM	#11
burnsauto Post Whore! Join Date: Dec 2006 Location: 717, PA Age: 39 Posts: 3,324 Trader Rating: (6) Rides Gallery: burnsauto Feedback Score: 6 reviews	check timing first, then the wastegate, piping leak, etc. go to advance/autozone/etc and buy a $20 boost gauge... just something to get you by so you know what psi you're running. (put a T fitting between the fuel pressure regulator, and the throttle body vacuum line, and run the boost gauge signal line off that.) __________________

06-18-2009, 03:37 PM	#13
waynehead05 Zilvia Junkie Join Date: May 2005 Location: Dallas Age: 38 Posts: 466 Trader Rating: (1) Feedback Score: 1 reviews	one way to check if you're boosting or not is pull the wastegate signal off completely. Start the car and ONLY go down the block and back. Punch it, but don't go past 5k. You'll know if you're boosting or not, cause it should boost upwards of 20 pounds. If it isn't boosting it's not your wastegate. __________________ Who in their right mind would want to lead this nation of Me-First Right-Now Do Nothings??

06-07-2012, 05:20 PM	#14
highlifein909 Zilvia Junkie Join Date: Nov 2011 Location: i.e. Age: 31 Posts: 436 Trader Rating: (3) Feedback Score: 3 reviews	YO! i need some help., recently my car was running fine, nd outa the no where car made a small boom noise from exhuast nd shutted down, i restarted it and after the car wasnt holding boost, after tryin to BOOST it while driving car shut off, car is idling fine but smells rich, no funny or knocking noises, can it be my turbo? wastegate or turbo leak???

06-11-2012, 10:53 PM	#15
sandeezy Join Date: Apr 2011 Location: valencia, ca Age: 37 Posts: 43 Trader Rating: (0) Feedback Score: 0 reviews	check all your exhaust gaskets most definitely. exhaust leaks = boost leaks and they can throw you off bad.

06-12-2012, 06:48 AM	#16
kikcaffine Zilvia Addict Join Date: Aug 2009 Location: Marietta, Ga Posts: 713 Trader Rating: (2) Feedback Score: 2 reviews	My car did the same thing, the guy grabbed what he thought was a vac source off the cold pipe after the intercooler but before the throttle body (stock SMIC piping), re-routed the lines correctly (stock) and it works fine afterwards. Check to make sure your lines are routed to the correct locations on the throttle body.

06-13-2012, 12:11 AM	#17
steve shadows Post Whore! Join Date: Aug 2003 Location: LA and OC Posts: 8,202 Trader Rating: (5) Feedback Score: 5 reviews	A lot of times people diagnose problems like this and they can't figure out what in the world it is. It is often the CAS or base timing being off...i.e. you need to get a timing light and an old distributor wire and check your timing per FSM to make sure it's 15 BDTC on the crank so you're all setup right... Granted this is usually the problem if everything else checks out first. Another thing is to check the ground wire that goes from the coil pack harness to the back of the head/firewall as well. This usually comes loose and can cause a pretty annoying mis-fire right where you don't want it. __________________ Like Me on FaceBook !

06-13-2012, 12:28 AM	#18
Jesse SR20 Join Date: Nov 2007 Location: Rancho Santa Margarita CA Age: 47 Posts: 41 Trader Rating: (0) Feedback Score: 0 reviews	After you confirm your timing, and grounds, go to home depot and buy the parts to build a boost leak tester (you'll need an air compressor, or a hand pump of some kind). Search google and youtube for what I'm talking about. You can NOT visually inspect for boost leaks. You'd be amazed at how many leaks the average boosted setup has unless they pressure test it. __________________