Hello,
I bought a Nigerian used Toyota Corolla 2005 a few weeks ago, did the servicing and little fixes here and there but I noticed the fuel economy was bad, 2k fuel could only take me from my place at Ejigbo area to Lagos Island to Oyingbo and back home and the fuel indicator was already showing yellow, and all this trip without the use of AC ooo...I took the car for scanning and the code gotten shows the catalytic converter bank 1 is defective, which the mechanic explained that the catalyst has either gone bad or was removed and I need to buy a new catalyst. Went to price the catalyst and the seller was saying I could buy the half catalyst if I don't want to buy the full catalyst and that the 'half' would also work fine too and help improve the fuel economy.
The experts in the house,how could this be true?
Can a catalyst be cleaned/serviced if it has not been removed?
Is it possible to get the 'half' catalyst installed and fuel economy would turn back to normal as it is with Corollas?
Please I urgently need your expert advice.

Thank you all.

put d real scarning code here ..let ppl help you..it might not be catalyst really it can be oxygen sensor.. so let see d code

and when u say 2000 fuel for 13km trip? u mean 26km trip to and fro.... cos I stay close to Ejigbo as well and oyingbo through the Lagos island should be more than 13km going then to and fro nko.... u need to check ur map again oh

traffic situation I ply that route everyday and spend close to 6hrs daily on the road due to traffic esp when going back @ that aswani nnpc route.... that place is crazy

with AC ET all I spend close to 2k to and fro.... anyways we don't drive same cars and the distance I cover is more....by a few kms

modified, I actually spend exactly 1500 to and fro (78km) with traffic upandan which translates to roughly 18mpg with the current issue in filling stations scam here and there.... where I buy fuel (petrocam, cos they are the only ones that have opened for biz when I leave the house), I have filled my tank from reserve and their meter was showing me 80ltrs+ for an 18.6gallon vehicle. so the fuel is never metered correctly. which gives me approximately 20+ mpg for a 78km 6hr ride.

my scanner still gives me factory mpg consistently with no cel.

and I'm talking about a 2.4ltr banger.

so there is something wrong with ur corolla. it might be catalyst related or not but if the scanner doesn't give u any codes and ur fuel trims are within spec then catalyst it is. BTW look for a wide spectrum scanner not just these cheap drive train scanners

before u start throwing parts, make sure someone learned gets involved cos sometimes the o2sensors may have been tweaked one way or the other. check for leaks and loose connections in the engine bay. u just might find an easy way out

with the poor fuel quality in the country now, it's not strange.

Taking my data for with that car ,even without catalyst ,your MPG will average around 24mpg ie 10km per litre which prove that absence of catalyst for that model of car is not significant .
If you experiences poor fuel mileage with your corolla ,look beyond catalyst for the culprit.

I appreciate your responses and I am really grateful. The scan code was : Catalysm efficiency low threshold bank 1.

inikamoze:
I appreciate your responses and I am really grateful. The scan code was : Catalysm efficiency low threshold bank 1.

Get a toks catalytic converter. Nothing like half catalyst. To me it means a compromised catalytic converter

Change your car's mass air flow meter. Thank me later