Engine going into Open Loop mode Randomly - Cultus VXRi 2008

[aminjafer5441]

I'm using SZviewer app to view the real time diagnostics. After driving for a while the engine enters closed loop mode as it should but then randomly it will enter open loop mode and stay in open loop mode for very long. I can also notice the affect of this as the rpm suddenly reduces and car pick and response is a bit slow.
During this time I can see that the Lamba sensor is not consistently giving voltage output i.e it stop giving any voltage intermittently. Could this mean that the sensor is bad or can it be cleaned and reused? Also there is no CEL.

[dms664]

is there any similar app like szviewer for toyota?

[zakiuddin]

I never knew that Cultus had an O2 sensor rather an AFR.
I won't fix something that ain't broken. Maybe the system is not designed to stay in closed loop all the time.

[RehanBhatti]

Cultus ecu will never go in closed loop at idle even you keep it starts for hours. It will go to closed loop only when you drive the car regardless engine temprature.You can monitor this transition by seeing real time scanner data while driving. Btw, your LTFT is quite good. What mileage you get per liter nowadays?
Here is my scan shot after driving few kms.

My LTFT is high positive. I think, its due to low fuel pressure. I need to check fuel pressure soon.

[aminjafer5441]

Basically I only took screenshots when the car stopped but the open loop remains even when car is moving at steady speed sometimes and I can feel the difference in engine response.
The fuel average calculated in city with AC on in morning and off at night is around 17km/l.
I know this seems impossible but I've recently filled up the tank again with 18.7 litres and trip meter reads 330km.
Also I've changed my driving style by using very light foot and putting car in neutral going down slopes.

Also just to confirm at what temperature does your auto fan start? Mine starts at 98 and turns off at 92 degrees.

[RehanBhatti]

Try to make a short video clip when engine is in closed loop. I just want to see your O2 sensor voltage variation.

[aminjafer5441]

Sure I will do that shortly and post back

[RehanBhatti]

Radiator fan turning ON and OFF tempratures are same as yours. Do you have any idea that which temp thermostat your engine has? I have installed 82°C in mine.

[iqbalu140]

Did you use an obd2 scanner? Can link it?

[aminjafer5441]

I'm currently running without thermostat as the housing needs to be changed, it's badly corroded. I'll be adding it before winter hopefully.

[RehanBhatti]

Use exact model with SZviewer app.
https://m.aliexpress.com/item/4000666381992.html?pid=808_0000_0131&spm=a2g0n.search-amp.list.4000666381992&aff_trace_key=&aff_platform=msite&m_page_id=8536aI-lZD2EnhnR5jfMc7sHk9bTV7FJgscGpjynSG_e9iHBU8Evid5UhMaxGTqYWDNR1590071085507&browser_id=8c8d0fb99a674b85a46da9f7cc9196b6&is_c=Y

[aminjafer5441]

https://www.daraz.pk/products/ancel-elm327-obd2-bluetooth-scanner-elm-327-v15-obd-2-auto-odb-car-diagnostic-for-engine-code-reader-diagnostic-tool-i130112970-s1289923709.html??dsource=share&laz_share_info=4389632_100_100_600014403376_3638524_null&laz_token=ee1c6c22b4d04a1611d3ce23f8c1d845

[RehanBhatti]

Dont wait for winter. Install a thermostat ASAP. Uncontrolled coolant temprature will often keep your engine in open loop.

[RehanBhatti]

What I noticed from this pic, your ignition timing is little too advance. It should be around 12° without any load on engine. It could be reason of your high rpm.

[aminjafer5441]

https://drive.google.com/file/d/1DRiVHrUjADnkwzKH7YL3SmWC4pUFs__C/view?usp=drivesdk
@RehanBhatti this is the video of diagnostics while car is running

[RehanBhatti]

Sorry for late reply. Your STFT and LTFT are perfectly fine. G10b ecu goes into closed loop only when driving. Even it goes in open loop at traffic light stops.

[engnr.mubashir]

Don't you think your battery voltages are low than normal.

[aminjafer5441]

I think the voltage in the picture was with peek electrical load, ac on, cabin blower at full, headlights and probably even the radiator fan was on all at idle. Else while driving it never goes below 13.5 volts.

[RehanBhatti]

Bro, my ecu never show correct voltage at scanner. I checked voltage many times with digital multimeter and it always are 13.7 volts with full load.

[engnr.mubashir]

You're directly checking on battery terminals. May be voltage at scanner are low due to old age wiring because copper also reduce efficiency by time and heat.