a/f readings - Zilvia.net Forums | Nissan 240SX (Silvia) and Z (Fairlady) Car Forum

mattysr20 · 05-03-2013, 02:35 PM

ok I made one thread about this and I saw the other guys thread about his readings. If a mod wants to delete my other thread that's cool I'm just making this one to try and clean things up a little so I hope people don't get mad I'm just frustrated and wanna figure this out cause the shop can't get me in till next week some time......

so anyways for starters
95 240 ax
s15 Sr20det
normal mods
turbo mani
Megan down pipe
3" cat back exhaust
stainless lines
Megan fpr
circuit sport grounding kit
turboxs bov
turboxs mbc
autometer wideband
HD fmic
Jim wolf tuned ecu
444 injectors
z32 maf
walbro inline fuel pump
12 gallon fuel cell in trunk

ok my issue is my wideband gives crazy reading all the time.
when its cold or cool out it stays at 14.7-15.0 sometimes going a little rich if I get into boost . but when its hot out it goes crazy even when not boosting at all it jumps from 15.0-10.0 and back up to 15.0-14.7 then jump around in between.
I've tried a few things but nothing helps at wot sometimes its rich and other times its lean so I can never tell what my exact reading is.
I do know my bov was leaking and might still be even though I put washers in also I'm pretty sure my fuel pump is going out cause it been acting and sounding funny lately. Is their something I could try? its driving me nut cause I don't want my car to be F-ed up.... I have a video of the wideband reading while driving I just don't know how to post it but I could email if someone wants to see it..

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mattysr20 · 05-06-2013, 04:13 PM

bump still need help

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mattysr20 · 05-07-2013, 10:39 AM

why does it only happen when hot out? last night it read perfect last night when it was cool out. It doesn't make sence

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Beemer · 05-07-2013, 07:51 PM

How is the sensor in the exhaust installed? Maybe to far away or maybe its not installed on the right angle and is getting moisture on it.

mattysr20 · 05-07-2013, 09:11 PM

ite on the top of the down pipe bout 3-4 inches from turbo

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Beemer · 05-07-2013, 09:40 PM

hmm i dont know if the auto meter wideband is any different then the aem ugeo one, but aem recommends 36 inches away from the turbo. I dont know if that will make a difference or not.

codyace · 05-07-2013, 09:44 PM

What does it read when WOT?

OnTheChip · 05-08-2013, 09:28 AM

Sounds like an exhaust leak that gets worse as things warm up.

Dave

mattysr20 · 05-09-2013, 09:28 AM

its usually going nuts but when good at wot it goes into 12s then other times it reads in 14s

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jsu1012 · 05-09-2013, 09:34 AM

Quote:

Originally Posted by OnTheChip

Sounds like an exhaust leak that gets worse as things warm up.

Dave

That's what i was thinking too.

OnTheChip · 05-09-2013, 09:44 AM

Other possibilities:

Intermittent fuel pump
non-recirculated/leaky bov
Intermittent MAF signal
Vacuum/boost leak

jovan344 · 05-09-2013, 10:19 AM

email me the video [email protected] it could be that you might have to alter the fuel tables in between rpms, is it in closed loop or open loop ? and does the afr jump around when youre on a constant speed like constantly on 3k rpm or so ? if you rook it to a dyno and they only did a power tune you still need to do your low speed fuel tables dyno tuners are lazy and only really mess with high speed fuel tables, I make my own street tunes, e to make the car run as smooth and light possible when cruising and actually feel the car pulling each and every bit as I accelerate

ultimateirving · 05-09-2013, 11:42 AM

Having the 02 sensor so close to the turbo is not recommended. It should be downstream a little further. If your plugging it into the factory 02 housing your doing it wrong.

Croustibat · 05-09-2013, 11:51 AM

Quote:

Originally Posted by ultimateirving

Having the 02 sensor so close to the turbo is not recommended. It should be downstream a little further. If your plugging it into the factory 02 housing your doing it wrong.

It works very well at that place, it only shortens the sensor lifetime as it gets hotter. Nothing a little radiator cant fix.

stuckonfresh · 05-09-2013, 01:33 PM

you could try AEM's sensor test to see if the sensor is still good. Basically you just have the sensor out of the exhaust but hooked up then turn the key to the on position, but DONT start the car! Afs should read super lean, be careful too bc the sensor gets hot. Then dampen a paper towel with brake cleaner and put it around the sensor- the Afs should go towards the max rich. If they fluctuate the sensor is most likely the problem.

Could look up the vid on youtube too, its by AEM and steph demonstrates it

05-03-2013, 02:35 PM	#1
mattysr20 Leaky Injector Join Date: Apr 2012 Location: ohio Age: 37 Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	a/f readings ok I made one thread about this and I saw the other guys thread about his readings. If a mod wants to delete my other thread that's cool I'm just making this one to try and clean things up a little so I hope people don't get mad I'm just frustrated and wanna figure this out cause the shop can't get me in till next week some time...... so anyways for starters 95 240 ax s15 Sr20det normal mods turbo mani Megan down pipe 3" cat back exhaust stainless lines Megan fpr circuit sport grounding kit turboxs bov turboxs mbc autometer wideband HD fmic Jim wolf tuned ecu 444 injectors z32 maf walbro inline fuel pump 12 gallon fuel cell in trunk ok my issue is my wideband gives crazy reading all the time. when its cold or cool out it stays at 14.7-15.0 sometimes going a little rich if I get into boost . but when its hot out it goes crazy even when not boosting at all it jumps from 15.0-10.0 and back up to 15.0-14.7 then jump around in between. I've tried a few things but nothing helps at wot sometimes its rich and other times its lean so I can never tell what my exact reading is. I do know my bov was leaking and might still be even though I put washers in also I'm pretty sure my fuel pump is going out cause it been acting and sounding funny lately. Is their something I could try? its driving me nut cause I don't want my car to be F-ed up.... I have a video of the wideband reading while driving I just don't know how to post it but I could email if someone wants to see it.. Posted from Zilvia.net App for Android

05-07-2013, 09:44 PM	#7
codyace Post Whore! Join Date: Dec 2004 Location: Poconos, PA Age: 40 Posts: 8,030 Trader Rating: (58) Feedback Score: 58 reviews	What does it read when WOT? __________________ *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

05-09-2013, 09:44 AM	#11
OnTheChip Zilvia Junkie Join Date: May 2013 Location: Burgaw, NC Posts: 318 Trader Rating: (0) Feedback Score: 0 reviews	Other possibilities: Intermittent fuel pump non-recirculated/leaky bov Intermittent MAF signal Vacuum/boost leak __________________ NismotronicSA - Speed-Density Tuning for Nissans

05-09-2013, 11:42 AM	#13
ultimateirving Zilvia FREAK! Join Date: Nov 2010 Location: arizona Age: 37 Posts: 1,521 Trader Rating: (1) Feedback Score: 1 reviews	Having the 02 sensor so close to the turbo is not recommended. It should be downstream a little further. If your plugging it into the factory 02 housing your doing it wrong. __________________ Z32 with lq4 swap Desert Street Scene \|\| Dssevents.com

05-06-2013, 04:13 PM	#2
mattysr20 Leaky Injector Join Date: Apr 2012 Location: ohio Age: 37 Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	bump still need help Posted from Zilvia.net App for Android

05-07-2013, 10:39 AM	#3
mattysr20 Leaky Injector Join Date: Apr 2012 Location: ohio Age: 37 Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	why does it only happen when hot out? last night it read perfect last night when it was cool out. It doesn't make sence Posted from Zilvia.net App for Android

05-07-2013, 07:51 PM	#4
Beemer Leaky Injector Join Date: Sep 2007 Location: regina,sask Age: 35 Posts: 94 Trader Rating: (0) Feedback Score: 0 reviews	How is the sensor in the exhaust installed? Maybe to far away or maybe its not installed on the right angle and is getting moisture on it.

05-07-2013, 09:11 PM	#5
mattysr20 Leaky Injector Join Date: Apr 2012 Location: ohio Age: 37 Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	ite on the top of the down pipe bout 3-4 inches from turbo Posted from Zilvia.net App for Android

05-07-2013, 09:40 PM	#6
Beemer Leaky Injector Join Date: Sep 2007 Location: regina,sask Age: 35 Posts: 94 Trader Rating: (0) Feedback Score: 0 reviews	hmm i dont know if the auto meter wideband is any different then the aem ugeo one, but aem recommends 36 inches away from the turbo. I dont know if that will make a difference or not.

05-08-2013, 09:28 AM	#8
OnTheChip Zilvia Junkie Join Date: May 2013 Location: Burgaw, NC Posts: 318 Trader Rating: (0) Feedback Score: 0 reviews	Sounds like an exhaust leak that gets worse as things warm up. Dave

05-09-2013, 09:28 AM	#9
mattysr20 Leaky Injector Join Date: Apr 2012 Location: ohio Age: 37 Posts: 92 Trader Rating: (0) Feedback Score: 0 reviews	its usually going nuts but when good at wot it goes into 12s then other times it reads in 14s Posted from Zilvia.net App for Android

05-09-2013, 10:19 AM	#12
jovan344 Join Date: Aug 2012 Location: brooklyn, NY Posts: 2 Trader Rating: (0) Feedback Score: 0 reviews	email me the video [email protected] it could be that you might have to alter the fuel tables in between rpms, is it in closed loop or open loop ? and does the afr jump around when youre on a constant speed like constantly on 3k rpm or so ? if you rook it to a dyno and they only did a power tune you still need to do your low speed fuel tables dyno tuners are lazy and only really mess with high speed fuel tables, I make my own street tunes, e to make the car run as smooth and light possible when cruising and actually feel the car pulling each and every bit as I accelerate

05-09-2013, 01:33 PM	#15
stuckonfresh Leaky Injector Join Date: Nov 2010 Location: in and out of areacodes Age: 39 Posts: 109 Trader Rating: (2) Feedback Score: 2 reviews	you could try AEM's sensor test to see if the sensor is still good. Basically you just have the sensor out of the exhaust but hooked up then turn the key to the on position, but DONT start the car! Afs should read super lean, be careful too bc the sensor gets hot. Then dampen a paper towel with brake cleaner and put it around the sensor- the Afs should go towards the max rich. If they fluctuate the sensor is most likely the problem. Could look up the vid on youtube too, its by AEM and steph demonstrates it