Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

Go Back   Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum > General > Tech Talk

Tech Talk Technical Discussion About The Nissan 240SX and Nissan Z Cars


Reply
 
Thread Tools Display Modes
Old 01-20-2013, 05:35 PM   #1
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
SR Rich idle/breaks up under boost

So i recently just did a s13 Redtop sr swap. At idle it runs between 10.0-10.5:1 a/f ratio, and cruising the car is perfect at 14.5-15.2:1 a/f ratio. Under boost it runs around 10.5:1 a/f, but once the car gets to 4lbs of boost it just breaks up bad and goes nowhere. Also when i start the car or let off the throttle it bogs down to around 200rpm then goes to 800rpm and idles beautifully. I'm running no bov, stock ecu and a ISIS t25/28 replacement turbo. Any help or insight would be appreciated. Thanks.
240nessx is offline   Reply With Quote
Sponsored Links
Old 01-20-2013, 05:48 PM   #2
Sliderintrainin
Zilvia Member
 
Sliderintrainin's Avatar
 
Join Date: Sep 2011
Location: NY
Posts: 266
Trader Rating: (12)
Sliderintrainin is an unknown quantity at this point
Feedback Score: 12 reviews
similar issue i was having.check every coupler for boost leaks.
Sliderintrainin is offline   Reply With Quote
Old 01-20-2013, 06:37 PM   #3
jamg
Nissanaholic!
 
Join Date: May 2009
Location: GA
Posts: 2,106
Trader Rating: (7)
jamg is an unknown quantity at this point
Feedback Score: 7 reviews
maybe it's a vac leak?
jamg is offline   Reply With Quote
Old 01-20-2013, 06:58 PM   #4
codyace
Post Whore!
 
codyace's Avatar
 
Join Date: Dec 2004
Location: Poconos, PA
Age: 40
Posts: 8,030
Trader Rating: (58)
codyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfectioncodyace is close to perfection
Feedback Score: 58 reviews
Send a message via AIM to codyace
Major vacuum leak or timing way off (or a combination).
__________________

Want Air Conditioning in your SR20 Swapped car? Check out www.sr20acbrackets.com for more information!

Quest Alternator Conversions for SR20! Check my Group Buy!

Tired of lousy internal gates? Go external wastegate with one of my manifolds, Check out my group buy
codyace is offline   Reply With Quote
Old 01-21-2013, 12:26 AM   #5
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
Alright, ill have to check tomorrow, the only vacuum lines are the fpr, wastegate, and charcoal canister? That all go to the throttle body?
240nessx is offline   Reply With Quote
Old 01-21-2013, 12:36 AM   #6
S14_BOSS
Leaky Injector
 
S14_BOSS's Avatar
 
Join Date: May 2012
Location: KALI
Age: 39
Posts: 137
Trader Rating: (4)
S14_BOSS is an unknown quantity at this point
Feedback Score: 4 reviews
Damn 10.1 AFR while idling? Super rich for idle.
Have you checked the spark plug gap?
S14_BOSS is offline   Reply With Quote
Old 01-21-2013, 01:11 AM   #7
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
No I'm goin to go over everything tomorrow. I assumed the plug gap was correct because there from Nissan, but I could be wrong.
240nessx is offline   Reply With Quote
Old 01-21-2013, 01:24 AM   #8
TheZ31Guy
Leaky Injector
 
Join Date: Jun 2012
Location: Houston
Posts: 102
Trader Rating: (0)
TheZ31Guy is an unknown quantity at this point
Feedback Score: 0 reviews
I would say vacuum leak. My car would run like total ass until I got into boost, found out I blew a coupler thingy majigger.
TheZ31Guy is offline   Reply With Quote
Old 01-21-2013, 03:56 AM   #9
cotbu
Post Whore!
 
cotbu's Avatar
 
Join Date: Sep 2005
Location: SWFL
Age: 50
Posts: 3,318
Trader Rating: (3)
cotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nice
Feedback Score: 3 reviews
Running in the knock map, with timing retarded! check ecu for codes, repair, reset, spend money on premium gas for a test, see if it clears up the idle richness then, boost it! report back.
__________________

LoverTechnologies "Half Broken Things!"
cotbu is offline   Reply With Quote
Old 01-21-2013, 06:24 PM   #10
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
So my spark plugs are gapped correctly, .028-.029, my fuel pressure is ~40psi, my timing is correct, and when I checked resistance on my coolant temp at around 122the when it should be about. 8ohms it was like 500ohms. So I'm goin to change that tomorrow and report back. Thanks for all the suggestions!
240nessx is offline   Reply With Quote
Old 01-22-2013, 03:15 AM   #11
cotbu
Post Whore!
 
cotbu's Avatar
 
Join Date: Sep 2005
Location: SWFL
Age: 50
Posts: 3,318
Trader Rating: (3)
cotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nicecotbu is just really nice
Feedback Score: 3 reviews
If you think it's the coolant temp sensor and if it is?, your ign timing cant be correct.
Another observation is your fuel pressure, is 40psi gonna assume with vacuum off and capped, cause that's how you check fuel pressure. your fuel pressure is low, noway you should be at 10.5afr unless injectors are leaking. You shouldn't hit 10.5 unless a whole pipe was disconnected. Also assuming good running engine.
__________________

LoverTechnologies "Half Broken Things!"
cotbu is offline   Reply With Quote
Old 01-22-2013, 04:32 PM   #12
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
my fuel pressure is low? I thought without vacuum it should be around 43-ish and with vacuum it should be around 37. With vacuum its at 40, so if anything i though it was good.

My injectors might be leaking then ill assume.

I checked the new sensor before i put it in, at room temperature and it was reading within spec. When i put it in the car, i checked it from the connector and its at around 300ohms. I guess that would mean there might be an open in the circuit or an air pocket in front of the sensor?
240nessx is offline   Reply With Quote
Old 01-23-2013, 01:39 AM   #13
Croustibat
Nissanaholic!
 
Join Date: Aug 2011
Location: France - Toulouse
Age: 44
Posts: 1,851
Trader Rating: (0)
Croustibat is an unknown quantity at this point
Feedback Score: 0 reviews
You got a huge boost leak somewhere, surely on your intercooler piping, or your crappy chinese turbo is cracked on the compressor side ( = boost leak again)

Or your MAF is unplugged meaning it cuts down at 2500rpm, but you would have said it.

As far as the FPR goes, your pressure is supposed to be 45psi + intake mani pressure, but if you just want to test your FPR you need to unplug its vacuum line (and block it); then it will be set at 45 psi all the time.

But if your FPR was bad, you would not be rich on boost.
Croustibat is offline   Reply With Quote
Old 01-24-2013, 04:53 PM   #14
240nessx
Leaky Injector
 
240nessx's Avatar
 
Join Date: Jun 2010
Location: 631 New York
Age: 32
Posts: 83
Trader Rating: (0)
240nessx is an unknown quantity at this point
Feedback Score: 0 reviews
I had a boost leak going from the turbo side to the intercooler. All fixed now, she pulls hard. (:
240nessx is offline   Reply With Quote
Reply

Bookmarks



Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump


All times are GMT -6. The time now is 07:34 PM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2025, vBulletin Solutions Inc.
vB.Sponsors
Copyright ? 1998 - 2022, Zilvia.net