chenge stochiometric afr

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m_abdi
Posts: 36
Joined: Tue Jan 05, 2010 9:05 am
Location: iran

chenge stochiometric afr

Post by m_abdi » Sat Jan 14, 2017 10:44 pm

hello world!
i have problem with 1227730 $88 tune.
when car is in cloose loop , test of exhust show co is about 0.4 and hc gas is above 400 and o2 is high. 'i check and see that o2 senesor tune afr 14.7 and it is too lean for idle. i want to tune that co gas come about 1.5~2 .beacuse of hc gas come down with richer idle.

the question is if i chenge stochiometric afr in ecu from 14.7 to 14 does ecu tune o2 sensor for work afew richer or i must do something else?

i found that 14.7 afr is lean for the car. how can i do that car tune richer in idle?
does idle volumetric chenge can help me or i must chenge something else for work richer in the idle?

thanks.

m_abdi
Posts: 36
Joined: Tue Jan 05, 2010 9:05 am
Location: iran

Post by m_abdi » Sat Jan 21, 2017 9:54 pm

any idea?

robertisaar
Author of Defs
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Post by robertisaar » Thu Jan 26, 2017 6:34 pm

changing the stoichiometric AFR value will change the fueling amount, but when the O2 sensor comes online, the fuel will be trimmed back to whatever value is determined to be relevant by the O2 sensor rich/lean/mean tables. shifting those values around will change the actual AFR while the ECM is in closed loop operation.

if you don't have an O2 sensor(I know some markets didn't receive them), then changing the stoich AFR value may not be what you are looking for. instead, I would look at the Open Loop AFR tables, since those should be relevant while in Open Loop.

m_abdi
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Joined: Tue Jan 05, 2010 9:05 am
Location: iran

Post by m_abdi » Tue Feb 07, 2017 5:45 am

thanks alot.
there is o2 sensor persent.

now,for have more rich idle in closed loop i must chenge rich/lean/mean table,ok , but i must increase the orginal number or decrease the valu to have more rich in idle?

robertisaar
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Post by robertisaar » Tue Feb 07, 2017 6:19 am

increase the value for a richer mixture. be aware that fairly small changes here can produce significant results. I believe the resolution is 4mV, I would recommend changing those values in no more than 8mV steps between testings.

also be aware that there may be scalars used specifically for idle that function in the same manner.

m_abdi
Posts: 36
Joined: Tue Jan 05, 2010 9:05 am
Location: iran

Post by m_abdi » Tue Feb 07, 2017 10:53 pm

i increace about 50mv. but steel lean. in the exhust i must have about 2.0 co gas for good mixture. in open loop it,s about 3~4 but in cloose loop it,s very lean and CO gas is about 0.5 , o2 sensor in car is one wire.

do you think , may be o2 senor does not work well? i chenge it with another one but the result is same. or o2 sensor is not acutal part number for this car?
does one wire o2 sensor is compatbile for all gm car or not? (olds cutlass ciera 1990)

robertisaar
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Post by robertisaar » Wed Feb 08, 2017 7:35 am

are you changing all 3 tables or scalars by the same amount?

m_abdi
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Location: iran

Post by m_abdi » Sun Feb 12, 2017 5:18 am

yes sir.
i put to voltmeter in o2 socket. it.s about 0.34v 0.4 v and sometime go to the .47 v in idle. and sometime in idle check light will on an set code 45.

i read some where that i must use silicone or anti-seize. but i dont do that.

m_abdi
Posts: 36
Joined: Tue Jan 05, 2010 9:05 am
Location: iran

Post by m_abdi » Mon Feb 20, 2017 5:56 am

any idea?

robertisaar
Author of Defs
Posts: 962
Joined: Sat Feb 21, 2009 3:18 pm
Location: Camden, MI

Post by robertisaar » Mon Feb 20, 2017 9:31 am

the fact that it's setting code 45 even with a new sensor is odd. I have a pretty good idea of why though. the way the MPFI 60V6 masks calculate idle fueling takes MAP, baro, TPS and IAC into account to make a pseudo alpha-n or MAF value. if any of those values are less than optimal, you get strange fueling results. this mode can be disabled and a normal speed-density calculation used instead. i'll have to look into it more after getting home(if I can remember). in the mean time, I would make sure the MAP, TPS and IAC are in good shape and you may fix your issue without having to change anything in the calibration.

m_abdi
Posts: 36
Joined: Tue Jan 05, 2010 9:05 am
Location: iran

Post by m_abdi » Wed Feb 22, 2017 6:11 am

thanks.
infact our car does not have any o2 sensor. it,s work in open loop. gm disable o2 senor for leaded fuel gas in 1990 in our area. now i enable ecm and install o2 sensor. but when car go to close loop , it,s very lean and co gas in exhust is about 0.4 but noramlly must be between 1-2 . our car does not have catalist.
but it,s very amazing that car in close loop in idle is lean but set code 45?!!!

i think it must set code 44 for lean.

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