Club-S12 International S12OC United Kingdom ClubS12 France S12Silvia Australia S12.org.ua Eastern Europe S12 of Sweden S12 Japan BBS
Please login or register.

Login with username, password and session length

Author Topic: Mixture adjustment??  (Read 1865 times)

Offline Keith

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: B-ham, AL
  • Posts: 5,970
    • http://www.cardomain.com/id/1984rps12
Mixture adjustment??
« on: 02:07:15 AM / 15-Oct-05 »
Since I put on the t25g, ss auto chrome o2 pipe, and full 3\" mandrel exhaust with no cat........at idle my a/f gauge no longer sweeps back and forth like it did before the swap......it just sits there on the first \"lean\" led.  At cruising speed it sweeps as normal, and under boost it shows rich like before.
Also at idle, the red and green ECU lights don\'t blink.....instead they both stay solid......which brings me to my question.  In the FSM it says if the ecu lights don\'t blink at idle, adjust the mixture screw on the air flow meter until the lights blink......which indicate the mixture is correct.  Has anyone tried this????  It shows to remove that rubber cap on the electrical box on the AFM, then drill through an aluminum cover to reveil the adjusting screw.
Is this a simple task? I\'m thinking with the new exhaust and lack of back pressure from the stock system.......the mixture is off as it smells rich at idle. It\'s only been about 100 miles with the new turbo and exhaust system......will the ECU re-learn ???

Facebook Share    




*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

*2007 BMW M6* S85 V10 sweetness

*2004 C5 Z06*

*2006 BMW E60 550i Sport* Boner stock; SOLD *

*1995 Maxima* Owned since 1995 SOLD

Car Domain

Offline Indecisive

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: Surrey, BC
  • Posts: 4,425
    • http://
Mixture adjustment??
« Reply #1 on: 02:10:22 AM / 15-Oct-05 »
I suggest you spend some $$ and get yourself an apexi safc or safcII or some type of air flow converter.  

it\'ll give you more tunability.  every 500rpm on the safc and every 100rpm on the safcII
Quote
"I'm fairly sure that if they took porn off the internet, there'd only be one website left, and it'd be called 'bring back the porn'"

Offline lmedeiros

  • Full Member
  • ***
  • Location: Tracy, California
  • Posts: 557
    • http://www.myspace.com/louiemedeiros
Mixture adjustment??
« Reply #2 on: 02:34:11 AM / 15-Oct-05 »
Well I just learned today from a very knowledgeble Japanese tuner that unless you get a good quality air fuel gauge it\'ll never be acurate. A good one meaning you\'ll be spending anywhere between $800-$1000 for one. I\'d say get a exhaust temp gauge and use that, far better for more precise readings. Also for you guys out there looking to buy a Apexi product beware because there are tons of fake ones out there. On apexi\'s website they are warning people of there products being copied.
Louie
87 s12 xe
CA18DET, S13 transmission, XS Power FMIC, HKS intake, HKS Iridium plugs, HKS SSQV, XO2 Racing Polished Exhaust Manifold, Turbo XS Dump pipe, Blitz down pipe, Grant steering wheel, Nismo Racing seats, Short Shifter, Drift E-brake Knob, Megan Racing gauges, Turbo Timer, JVC deck, Blaupunk Components, Powerstop Cross Drilled Rotors, SSC Springs, 5 Way Tokico illuminas, Sportmax wheels.


Offline Eddy

  • Full Member
  • ***
  • Location: Toronto, Canada.
  • Posts: 603
    • http://
Mixture adjustment??
« Reply #3 on: 03:37:47 AM / 15-Oct-05 »
a/f guage is basically useles..  unless you get the one you mentioned for 800+  .. that\'s a wideband o2 sensor....     which is a waste of moeny b/c you can pay a dyno place and you can tune your car w/ their wideband for less than what you purchase one for..
1988 200sx sr20det - turbo
1991 240sx ca18det - turbo
2008 VW GTI - FSiT - turbo

:D

Offline Keith

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: B-ham, AL
  • Posts: 5,970
    • http://www.cardomain.com/id/1984rps12
Mixture adjustment??
« Reply #4 on: 12:12:46 PM / 15-Oct-05 »
you guys must not be reading ALL of my first post.............I mentioned the ECU lights don\'t blink anymore at idle either.....where they did before the swap, and too the sweeping a/f gauge @ idle.
FSM says ECU lights should blink @ idle.....and if not that adjusting screw need to be adjusted until they do blink.



*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

*2007 BMW M6* S85 V10 sweetness

*2004 C5 Z06*

*2006 BMW E60 550i Sport* Boner stock; SOLD *

*1995 Maxima* Owned since 1995 SOLD

Car Domain

Offline falkhen

  • Full Member
  • ***
  • Location: Greater Houston Area
  • Posts: 780
Mixture adjustment??
« Reply #5 on: 12:36:32 PM / 15-Oct-05 »
kieth. your not the only one in that boat.

I am  running a T25G with SS autocrome dump single non-divorced with 3\" exhuast and 3\" cat

the problem is here

their is to much flow and larger percent of exhuast gases are not being read by the O2 sensor.( i was running with out a cat) i installed a 3\" catilytic converter and it started sweeping again at idle. and made it easier to start..

problem started with too much flow.
problem ends with a little restriction

another suggestion is to relocated the O2 so that it see\'s larger portion of the exhuast.

or take a grinder and shave the o2 sensor bung on the dump so that is half as tall....i thought it was little on the large side.



falkhen

Offline Cavi Mike

  • Full Member
  • ***
  • Location: Rochester, NY
  • Posts: 852
    • http://
Mixture adjustment??
« Reply #6 on: 12:56:56 PM / 15-Oct-05 »
Cars always run super lean at idle, at least in the turbo-charged world they do. If you want a real reading, you need to get yourself a 4-wire O2 sensor. But they don\'t last for very long, they\'re meant to be used at the dyno where you tune your car then put the 1 wire back in, then leave all adjustments alone.
http://www.myspace.com/cavimike

------------------------
All Cars Would Be Yellow If Not for the Matchy-Matchy Laws
Teacher: So, as you can see, this car in the picture reduces air resistance and can accelerate faster.
Student #1, chuckling: Yeah, and plus, it's yellow, so that makes it faster, too.
Teacher, laughing: Haha, yeah, very true.
Student #2: Wait, really?

--Physics class, St. Ann's School

Overheard by: Mike N
------------------------

Offline Keith

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: B-ham, AL
  • Posts: 5,970
    • http://www.cardomain.com/id/1984rps12
Mixture adjustment??
« Reply #7 on: 10:53:44 PM / 15-Oct-05 »
anyone actually mess with the adjusting screw on to afm to correct the mixture??



*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

*2007 BMW M6* S85 V10 sweetness

*2004 C5 Z06*

*2006 BMW E60 550i Sport* Boner stock; SOLD *

*1995 Maxima* Owned since 1995 SOLD

Car Domain

Offline bartc_j

  • Questionable Seller/BUYER BEWARE
  • S12 Guru
  • *****
  • Location: boise, idaho
  • Posts: 10,725
    • http://members.cardomain.com/bartc_2
Mixture adjustment??
« Reply #8 on: 02:51:30 PM / 17-Oct-05 »
Quote
a/f guage is basically useles..  unless you get the one you mentioned for 800+  .. that\'s a wideband o2 sensor....     which is a waste of moeny b/c you can pay a dyno place and you can tune your car w/ their wideband for less than what you purchase one for..


the only good the basic autometer unts are good for is to give you a quick view of possible problems under hard acceleration.. ie if you\'re gunning it and the af gauge goes lean its a good idea to get off the throtle
Bart
 '86 1.8L Turbo

Offline bartc_j

  • Questionable Seller/BUYER BEWARE
  • S12 Guru
  • *****
  • Location: boise, idaho
  • Posts: 10,725
    • http://members.cardomain.com/bartc_2
Mixture adjustment??
« Reply #9 on: 02:53:20 PM / 17-Oct-05 »
Quote
anyone actually mess with the adjusting screw on to afm to correct the mixture??


you can do this but you will need a nice aftermarket wideband o2 unit to meter the mixture exactly... also im not sure if that kind of adjustment willl alter the whole fuel curve or only the idle
Bart
 '86 1.8L Turbo

Offline Keith

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: B-ham, AL
  • Posts: 5,970
    • http://www.cardomain.com/id/1984rps12
Mixture adjustment??
« Reply #10 on: 12:38:16 PM / 20-Oct-05 »
Quote
i installed a 3\\\" catilytic converter and it started sweeping again at idle.  
falkhen

Cool thanks......I\'m thinking about getting one.  What brand did you go with?  Is it quiter now with the cat?  A little quiter would be nice......it\'s a little LOUD for long distance driving.
I keep getting the AFM code(12)......I\'m wondering if the lack of back pressure has anything to do with it?



*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

*2007 BMW M6* S85 V10 sweetness

*2004 C5 Z06*

*2006 BMW E60 550i Sport* Boner stock; SOLD *

*1995 Maxima* Owned since 1995 SOLD

Car Domain

Offline bartc_j

  • Questionable Seller/BUYER BEWARE
  • S12 Guru
  • *****
  • Location: boise, idaho
  • Posts: 10,725
    • http://members.cardomain.com/bartc_2
Mixture adjustment??
« Reply #11 on: 01:11:09 PM / 20-Oct-05 »
Quote
Cool thanks......I\'m thinking about getting one.  What brand did you go with?  Is it quiter now with the cat?  A little quiter would be nice......it\'s a little LOUD for long distance driving.
I keep getting the AFM code(12)......I\'m wondering if the lack of back pressure has anything to do with it?


catco makes nice high flow cats.. summit racing carried them.. just get a universal unit
Bart
 '86 1.8L Turbo

Offline Keith

  • Honored Veterans
  • S12 Guru
  • *****
  • Location: B-ham, AL
  • Posts: 5,970
    • http://www.cardomain.com/id/1984rps12
Mixture adjustment??
« Reply #12 on: 01:16:38 AM / 22-Oct-05 »
the adjusting screw......if it\'s not adjusted right......will it throw a code 12?



*1984 S12 Turbo* CA18DET swap * Custom top mount header & dump pipe * Mitsu Heavy Industries EVO III 16g turbo * Custom 3" turbo back exhaust with Magnaflow muffler * Front mount intercooler * Front mount oil cooler * Nismo fuel pressure regulator * Walbro 255 * DSM 450cc Injestors * Apexi Safc II * AEM Wide Band * AEM Tru Boost * Z32 MAF * Cometic head gasket * Centerforce Dual Friction clutch *  Tokico lowering springs * Owned since 1989 *

*2007 BMW M6* S85 V10 sweetness

*2004 C5 Z06*

*2006 BMW E60 550i Sport* Boner stock; SOLD *

*1995 Maxima* Owned since 1995 SOLD

Car Domain