General runing rich (open loop)

[dawid4444]

i have a problem with my 98 GSX .
So my car is running rich , i can say that becasue i smell gas from my exhaust and i get low gas millage and the car just dont pull hard like it used to :/

when i look on my scan tool and when the engine is cold it says
"(closed)open loop"

and when car is warm it says
"open loop"

is that right ??

i think when car is fully warmed up it suposed to be "closed loop"

what could caused this ??


idk i NEED help

thank you guys

btw sorry for my english
im not in USA for long time

thx again

anyone ?? ;(

 

[steve]

Once the car is warmed up at idle is should be in closed loop.

On a 2G any one of the following will cause the ECU to not enter closed loop.

Throttle position too high
Airflow too low
Engine Coolant temp < 51F
Engine Coolant temp > 228F
The O2 sensor did not cycle for the last 128 seconds while running in closed loop mode.

In addition for it to update the fuel trims while it's in closed loop all of these have to be true
Engine Coolant temp >= 180F
Intake air temp < 133F
22.9 inHg <= Baro <= 31.6 inHg


Hopefully your scan tool will let you look at these.

 

[dawid4444]

ok my is in open loop when its warmed up at idle :/

ok so


Throttle position too high = idk how to check it ;/
can u tell me how to check if it is too high ??

Airflow too low = idk how to check it too
airflow where ?? in the intake ??

Engine Coolant temp = its ok cause i check it during driving and at idle and its all good
O2 sensor = is ok too


so can u tell me how to check Throttle position and Airflow ??

im really mad cause my car was driving great and pulling hard and now its like 70% of power :/

thank you soo much

 

[dawid4444]

my o2 sensor was bad for sure like 2months ago
i did replace it and now its working fine for sure

but it says

"The O2 sensor did not cycle for the last 128 seconds while running in closed loop mode."


the new one never run in closed loop because the ECU locks itself in open loop mode.

so SHOULD I JUST RESET THE ECU AND IT WILL GO IN Learn mode
than it will see that the o2 sensor did cycle and will go in clossed loop ??

what do u guys think ??

thx a lot

 

[steve]

Every time you restart the car it will try to go into closed loop once it's warmed up.

I don't have a OBD II scantool so I can't tell you how to check the values on yours. The Airflow check is very unlikely unless you have a bad MAS and I think you would need something that does the MUT protocol to check it.

Your profile lists various upgrades but I don't see injectors or any tuning system.

 

[dawid4444]

ill try to restart the ecu today

if it doesnt help ill change the MAS and see

yeah my injectors are stock

thx a lot steve

 

[steve]

if it doesnt help ill change the MAS and see

Why?
If you don't have clear indications that a part is bad you don't just change it.

 

[dawid4444]

i mean i will just try my friends MAS that im sure its working

cause i dont know what to do with that open loop :/
my o2 sensor is good
my Engine Coolant temp are ok
MAS hmm i realy dont know how to check it ;/
but the intake air temperature is ok cause i chceck it too

could be my ECU bad ???
maybe my Capacitors in the ECU are loose ??

guess what guys

i did restart my ECU and now the car is in closed loop

thx a lot to steve

lil lesson for everybody when u change the o2 sensor just restart your ecu and you will be good


ill mark it as resolved

thx again

 

[steve]

That's great.

In rethinking about resetting (disconnecting the battery) vs restarting the one thing that could be a factor is the long term fuel trims. If the sensor was bad for a while the trims could be off and clearing them by disconnecting the power would help by giving you a clean start when you replace the sensor.

 

[turboglenn]

You know i was logging/troubleshooting a WRX the other day that had the same issue, it would be rich, but uner boost it went lean and teh ECU would stick in open loop.... told him to change his fuel filter and that solved it.... was a lucky guess but enough time fighting OBD-II can teach you a lot. Might wanna check and replace the FF just in case and reset the ECU

 

[dawid4444]

thx again guys
thx for your help

 

[elterror]

When you restard, what method did you use? Just unplugged the battery?