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 06-11-2019, 05:30 PM   #1
dirtdiggler666
Nissanaholic!
 
dirtdiggler666's Avatar
 
Join Date: Oct 2006
Location: p-dale
Age: 44
Posts: 2,113
Trader Rating: (26)
dirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfection
Feedback Score: 26 reviews
2JZ afr question

Ok I am running a stock 2JZGTE VVTI with a small single turbo and everything else stock. I was running about 7LBS open wastegate and the afr was always right around 11.5 then I decided to recirculate the wg into the downpipe and now my afr is right around 10.5

Has this happened to anyone? anything I can do before I go standalone?
__________________
dirtdiggler666 is offline   Reply With Quote
Sponsored Links
Old 06-12-2019, 10:42 AM   #2
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 40
Posts: 4,827
Trader Rating: (17)
Kingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond repute
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
What probably happened is,

increased exhaust gas pressure = less efficient engine = less airflow through engine = richer air fuel ratio = less power

Another possibility is you created a boost leak somewhere by accident.

What can you do? You mean on stock injectors/maf/map?
-An SAFC can pull 10% fuel without any harm bring it back to 11's
-reduce fuel pressure slightly
-check for boost leaks
-raise the boost pressure (the higher you go, the leaner it gets... ah haha...)
Kingtal0n is offline   Reply With Quote
Old 06-12-2019, 07:46 PM   #3
dirtdiggler666
Nissanaholic!
 
dirtdiggler666's Avatar
 
Join Date: Oct 2006
Location: p-dale
Age: 44
Posts: 2,113
Trader Rating: (26)
dirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfection
Feedback Score: 26 reviews
Quote:
Originally Posted by Kingtal0n View Post
What probably happened is,

increased exhaust gas pressure = less efficient engine = less airflow through engine = richer air fuel ratio = less power

Another possibility is you created a boost leak somewhere by accident.

What can you do? You mean on stock injectors/maf/map?
-An SAFC can pull 10% fuel without any harm bring it back to 11's
-reduce fuel pressure slightly
-check for boost leaks
-raise the boost pressure (the higher you go, the leaner it gets... ah haha...)
All very good points.

I think first I will make a boost leak tester, I should have one anyways.
its on a maf and yes stock injectors so any piggy back worth a damn?

Its weird tho the higher I go on psi the fatter it gets? I would of thought it would have done the opposite thing.

If all else fails just to prove I'm not crazy I might just build another downpipe and vent the Wastegate to see if it goes right back to 11.5
__________________
dirtdiggler666 is offline   Reply With Quote
Old 06-13-2019, 08:40 AM   #4
Janz99
Leaky Injector
 
Join Date: Mar 2007
Location: Winnipeg, Canada
Age: 41
Posts: 59
Trader Rating: (0)
Janz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the roughJanz99 is a jewel in the rough
Feedback Score: 0 reviews
Quote:
Originally Posted by dirtdiggler666 View Post
All very good points.

I think first I will make a boost leak tester, I should have one anyways.
its on a maf and yes stock injectors so any piggy back worth a damn?

Its weird tho the higher I go on psi the fatter it gets? I would of thought it would have done the opposite thing.

If all else fails just to prove I'm not crazy I might just build another downpipe and vent the Wastegate to see if it goes right back to 11.5
Id put a fresh set plug in at least one of the cylinders and make a pull. Then remove the plug and see if the plug looks appropriate for the A/F you are seeing.

Are you using a wideband? If yes, what brand/model. Its possible that your o2 sensor is starting to fail and its just a coincidence that it happened at the same time you did the WG recirc. Pulling a plug will either confirm or rule out an o2 sensor problem.

I also agree, check for boost leaks on the charge side.

-Ryan
Janz99 is offline   Reply With Quote
Old 06-13-2019, 02:37 PM   #5
TheRealSy90
Post Whore!
 
TheRealSy90's Avatar
 
Join Date: Mar 2009
Location: Maricopa, AZ
Age: 33
Posts: 7,721
Trader Rating: (10)
TheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant futureTheRealSy90 has a brilliant future
Feedback Score: 10 reviews
Fix boost leaks, then raise the boost pressure until it leans out lol.
__________________
Quote:
Originally Posted by crimsonrockett View Post
Such a good signature.
TheRealSy90 is offline   Reply With Quote
Old 06-16-2019, 12:31 PM   #6
dirtdiggler666
Nissanaholic!
 
dirtdiggler666's Avatar
 
Join Date: Oct 2006
Location: p-dale
Age: 44
Posts: 2,113
Trader Rating: (26)
dirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfection
Feedback Score: 26 reviews
Quote:
Originally Posted by Janz99 View Post
Id put a fresh set plug in at least one of the cylinders and make a pull. Then remove the plug and see if the plug looks appropriate for the A/F you are seeing.

Are you using a wideband? If yes, what brand/model. Its possible that your o2 sensor is starting to fail and its just a coincidence that it happened at the same time you did the WG recirc. Pulling a plug will either confirm or rule out an o2 sensor problem.

I also agree, check for boost leaks on the charge side.

-Ryan
I have not had time to build a boost leak tester yet. but I raised the boost to 13 psi made a few pulls and it was right around 10.5 to 10.3 then I checked the plugs and they were very white and clean looking.

my AFR gauge is only a few hundred miles old and its a AEM X Series

Could the WG be causing turbulence in the downpipe and giving a faulty reading?
__________________
dirtdiggler666 is offline   Reply With Quote
Old 06-16-2019, 01:40 PM   #7
Kingtal0n
Post Whore!
 
Kingtal0n's Avatar
 
Join Date: Jul 2005
Location: South Florida
Age: 40
Posts: 4,827
Trader Rating: (17)
Kingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond reputeKingtal0n has a reputation beyond repute
Feedback Score: 17 reviews
Send a message via AIM to Kingtal0n
it goes

maf -> computer -> injectors

so,
its either the maf, computer, or injectors (and related)

->things that f#$*& with maf:
wrong maf
bad maf
bad maf wiring
bad maf grounding
poor maf placement (too close to turbo, turbulent tube, no recirculated bypass)
leaky maf plumbing (boost leaks and air leaks)
improper use of maf (boost leaks, blow off valves, poorly designed tubes, non recirculation bypass)

!>computer issues related to rich a/f ratio:
bad ecu grounding(corrosion), bad (maf/tps)sensor grounding
poorly tuned, improperly tuned
wrong maf
(unrelated note to check timing)

☼¶injectors issues general store for rich a/f ratio:
leaking injector O-rings
too much fuel pressure (rare)
Injector too large for idle speed/minimum pw (2000cc injectors)
Kingtal0n is offline   Reply With Quote
Old 06-17-2019, 08:24 PM   #8
dirtdiggler666
Nissanaholic!
 
dirtdiggler666's Avatar
 
Join Date: Oct 2006
Location: p-dale
Age: 44
Posts: 2,113
Trader Rating: (26)
dirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfectiondirtdiggler666 is close to perfection
Feedback Score: 26 reviews
Quote:
Originally Posted by Kingtal0n View Post
it goes

maf -> computer -> injectors

so,
its either the maf, computer, or injectors (and related)

->things that f#$*& with maf:
wrong maf
bad maf
bad maf wiring
bad maf grounding
poor maf placement (too close to turbo, turbulent tube, no recirculated bypass)
leaky maf plumbing (boost leaks and air leaks)
improper use of maf (boost leaks, blow off valves, poorly designed tubes, non recirculation bypass)

!>computer issues related to rich a/f ratio:
bad ecu grounding(corrosion), bad (maf/tps)sensor grounding
poorly tuned, improperly tuned
wrong maf
(unrelated note to check timing)

☼¶injectors issues general store for rich a/f ratio:
leaking injector O-rings
too much fuel pressure (rare)
Injector too large for idle speed/minimum pw (2000cc injectors)
Thanks for all the info

Hopefully I will figure it out soon
__________________
dirtdiggler666 is offline   Reply With Quote
Reply

Bookmarks


Thread Tools
Display Modes

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 08:09 AM.


Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2024, vBulletin Solutions Inc.
vB.Sponsors
Copyright ? 1998 - 2022, Zilvia.net