And i tot 17mpg was poor on my 2.4 liter 4 banger. lol. Ive been trying endlessly to improve the mpg city endlessly. Well, putting an end to my quest now. Cheers nissparts.

nissparts: Incorrect. I sell brand new original air filters

Do u av original air filter for camry 2007 4cyl. If u do, hw much is it

nissparts: What most Lagosians do not realize is that 17mpg for lagos city driving on our quality of fuel and engine oils is more than adequate for a 4 banger and you will not get better than that until you take a long trip on a highway.

If you buy a brand new Hyundai today for example, you will enjoy between 18-19mpg city driving depending on your route.
At 1000km you will have to take the vehicle in for the first service. Immediately after that service, your mpg will drop to 14-15mpg on the same route. Why? Quality of engine oil used.

Thanks. that is a whole new perspective to it. The quality of petrol is questionable, the weight of oil is also a problem, in my case the closest to the recommended 5-20W, i could find is Total's 5-40W.

nissparts: What most Lagosians do not realize is that 17mpg for lagos city driving on our quality of fuel and engine oils is more than adequate for a 4 banger and you will not get better than that until you take a long trip on a highway.

If you buy a brand new Hyundai today for example, you will enjoy between 18-19mpg city driving depending on your route.
At 1000km you will have to take the vehicle in for the first service. Immediately after that service, your mpg will drop to 14-15mpg on the same route. Why? Quality of engine oil used.

@nissan, do you happen to sell Techron fuel injector cleaner

No I dont

Good stuff but you can only carry out these procedures if you still have a cat in your exhaust system as most cars that have come into my workshop with emission related issues have had the cats gutted out from the casing.

I just had a 2008 Honda accord come in last week with the same p0420 code and on further investigation discovered that all the catalytic converters have been cleverly removed making the car less fuel efficient and the sound from the exhaust very hollow.

I must advise that you check your car's cat before leaving it for too long at a mechanic workshop.

[/quote]

JaaizTech: update: P0420 code is back. Hmmm sad, but car still drives better than before.

@nissan do you happen to have bando serpentine belts for accord 2003 2.4 litres engine.

Nissparts I'm also interested in the OEM serpentine belt for a 4cyl, 2003 accord LX. If you have it you can shoot me a quote for delivery to owerri via PM thanks.

nissparts: Incorrect. I sell brand new original air filters

Nisspart, do you have original new air filter for w202 Benz c180? If you do , how much is it, and how can i get it from you as i am living in PH?

Also, do you have the oxygen sensor spacer to sell alongside?

The spacer is available at 5k.
No air filter for Benz

sultaan: This question is for all to answer before doing anything then we can all improve our collective knowledge.

If your code says cat is inefficient, what sensor is there that determine it ?

Consider inefficiency is a reduced input to output ratio and the sender sensor that reads that is .....

catalyst inefficiency has nothing to do with the sensors. its road side mechanics that suggest those crap.
connect your OBD2 and switch to the spectrum graph mode you will see the performance of your sensors. if it goes bad, another code will pop up indicating bad sensors.

what you guys ignore is this; when the catalyst degrades, it is the sensor that sends the signal to the ECU before the check engine light turns on, now, how would you have check engine for catalyst and still say the sensor that alerted you is bad? does it make sense?
exactly what my mechanic told me but i ignored him.

i had catalyst inefficiency i came here and opened a thread, i got all sorts of advice till the catalyst burned off, my exhaust hollowed and my fuel consumption improved greatly.
though the wuuu! exhaust sound bothers me but the fact that i save fuel is worth it.

nissparts: The spacer is available at 5k.
No air filter for Benz

pls what size of spacer do you use for the oxygen sensor? my only interest is to protect the sensor from excessive fumes due to degraded cat.
degraded cat reduces exhaust back pressure which may reduce power but fuel consumption will improve, mine gained extra 3mpg when the cat degraded.
connect your OBD2 scanner and drive around.

jp philips:

pls what size of spacer do you use for the oxygen sensor? my only interest is to protect the sensor from excessive fumes due to degraded cat.
degraded cat reduces exhaust back pressure which may reduce power but fuel consumption will improve, mine gained extra 3mpg when the cat degraded.
connect your OBD2 scanner and drive around.

i think it is the other way round, a degraded/blocked CAT, will increase back pressure, hence causing your power to drop and also reducing your mpg. However, a hollowed CAT may also be regarded as a degraded CAT, with the effect of reducing back pressure, increasing mpg, and in addition making your car have a deep tone.
Well, my P0420 code has never returned since i ran my car using the Mobil Power injector cleaner. I have bought the highly recommended techron, to see if any extra improvements can be gained, esp. with mileage.

Nissparts, hi, do u have Atf-z1

I had the P0420 pop up a few days ago on my qx56. I just reset the SES (to buy me time until i got home and research d code properly). Before i got home, the SES light came on again but this time, 2 codes P0420 and P0430. I then investigated and found this to be a leakin exhaust pipe. The clip at d joint where the two pipes feed into one was d culprit. As soon as i looked under d car, i could see it leaking- water dripping. Had a new clip installed and tightened @ N400. All has been ok now for 300km. Whats more excitin is my mpg, which is now 11.6mpg (round town), compared to 10.8mpg b4. Result.

So, before changin cats or 02sensors, check 4 leakages.

By d way, i only saw two 02 sensors (before ) the cat and the leak was after d CAT. So wat detected d leak

JaaizTech:
To the best of my knowledge it is the back O2 sensor that signals that error code. From all i have read it is either ur O2 sensors are bad or the CAT is bad, on many American online fora, u re advised to change O2 sensors first because they are cheaper and easier to fix.

You are absolutely spot on.

To the best of my knowledge, most p0420 code issues that I have encountered have been cured by replacing the oxygen sensors. Try that first before changing your cat. Also check for proper contact at the connectors.

Car-Doctor.

nissparts: If you have a catalyst code and you replace an o2 sensor, 99% of the time you would have wasted your money

Not true. I had an Acura MDX that came to my workshop yesterday with the same code issue and once we replaced the o2 sensor the check engine light went permanently off and the code never came up again.

Car-Doctor.

Lol...sorry car doctor but if you are willing to learn on this subject then this is the place for you.
First you replaced a sensor yesterday and now claim a code is PERMANENTLY off. Do not be deceived,an 0420 or 0430 code will never come up for an o2 sensor fault. Pray tell, in either code, what info is it passing to you the owner? It is telling you the catalyst is degraded beyond its acceptable level and how does it know this? The o2 sensor does its job to highlight the anomaly. Now let's say for argument sake that the downstream sensor that does this job was bad and not mwasuring correctly, the system is not stupid, it has codes to tell u the sensor itself is either bad or its heater is bad. Summary, the code in that Acura will be back. As u can see in the OPs vehicle, it can take as long as 3wks sef but it will be back if all u did was change a sensor

jp philips:

pls what size of spacer do you use for the oxygen sensor? my only interest is to protect the sensor from excessive fumes due to degraded cat.
.

if you cut open a cat, you'll find out that the rear 02 sensor dosen't stick out much into the exhaust gas flow, that is just the size of your spark plug thread. Your auto spare parts dealer should be able to give you a spark plug extender that fit the size of your o2 sensor since the o2 sensor thread are the same as that of a spark plug. Just go to your dealer with your 02 sensor and get a spark plug extender that fit your thread, kaskia.

Alternatively you can locally make your own spacer , just pick 2 spark plugs(a bigger and a smallerone) and tear off the white component from after the threads and bore a hole through them just enough for the exhaust fumes to pass through, then screw the smaller one ontop of the bigger one that screws into your 02 sensor duct of your exhaust to fit in there, while the 02 sensor fit at the top of of the second one

Note also that the o2 sensors are used to control the fuel loop,the first set of o2 sensors are the ones that monitored the rich/lean/etc.

jp philips:

degraded cat reduces exhaust back pressure which may reduce power but fuel consumption will improve, mine gained extra 3mpg when the cat degraded.
connect your OBD2 scanner and drive around.

Only when you have hollowed out the clogging materials inside the cat else the reverse is the resultant effect.
I know some cars are design to have so much back pressure to control the emssion and protect the environment thus reducing power, but removing the back pressue can benefit in freeflow and performance and as well in better mpg

@Nissparts

No, you learn. The oxygen sensors detect the level of oxygen in the nitrogen oxide emission of vehicles. The catalytic converter breaks down the mole ules in the nitrogen oxide to make the vehicles emissions less toxic and also help to reduce smog.

Most cat codes here in nigeria are caused by poorly refined fuel or leaded fuel fuel being used on modern cars with advanced emission monitoring components such as the oxygen sensors, catalytic converters, MAF or MAP sensors, Evap etc.

Once contaminated fuel or unleaded fuel is used on modern cars you run the risk of damaging the oxygen sensors that's why there is always a warning on your fuel tank cover to make sure you fill your car with unleaded fuel. The reason why you are advised to do so is because the oxygen sensors are designed to work with higher octane rated fuel like unleaded RON 95/97.

In Nigeria, there are no standards for measuring the fuel you purchase at the petrol station because there is no indication on what you are buying so fuel dealers sell the fuels without any indicated ratings.

In most othercountries of the world, fuel RON (Research Octane Number) ratings are indicated on the pumps at the petrol stations so that you can make the choice for your car.

Using low octane or lead added petrol will sooner or later damage your oxygen sensors and cat as well as possibly ruining your engine. The leaded fuel is that deep red fuel that you will usually only get to see when poured into a container. Unleaded fuel is usually yellowish in colour.

Catalytic converters Don't usually or easily get damaged unless carbon deposits have built up in the catalytic converter to the point of clogging it up and rendering it incapable of carrying out its filteration duties.

It can als get damaged due to excessive temperatures burning it out as raw fuel is deposited into the exhaust system or the honeycomb ceramic structure breaking away.

Raw fuel deposits into the exhaust manifold is mostly caused by faulty injectors, ECU, MAF sensor or oxygen sensors.

If any of these components are faulty, a higher rate of nitrogen oxide emission will be indicated hence the enission related obd codes popping up.

I am an ATA ACCREDITED MASTER TECHNICIAN and I have resolved uncountable issues even in the UK where I had studied, worked andlived for over 16 years before returning to Nigeria. I also owned and operated an auto workshop with a MOT station.

Emission related issues are taken seriously in the UK as well as other developed countries of the world and in the UK we have to ensure that vehicles pass emission tests before a certificate is given. I face these challenges on a daily basis and I think I should be the one who informs you better on what to do.

Always start by scanning and checking the voltage fluctuations on your oxygen sensors. If the voltage readout is ok, check other related components and examine your cat if all else is ok.
Only change a cat when its physically damaged or clogged up with carbon. Washing or cleaning usually restores its functions back but let changing it be your last option as they can be very expensive to purchase while the main problem is still underlying.

Whatever you say dude

nissparts: Whatever you say dude

Whatever I say? Its not my theory. You can always look it up.

car-doctor:
@Nissparts

No, you learn. The oxygen sensors detect the level of oxygen in the nitrogen oxide emission of vehicles. The catalytic converter breaks down the mole ules in the nitrogen oxide to make the vehicles emissions less toxic and also help to reduce smog.

Most cat codes here in nigeria are caused by poorly refined fuel or leaded fuel fuel being used on modern cars with advanced emission monitoring components such as the oxygen sensors, catalytic converters, MAF or MAP sensors, Evap etc.

Once contaminated fuel or unleaded fuel is used on modern cars you run the risk of damaging the oxygen sensors that's why there is always a warning on your fuel tank cover to make sure you fill your car with unleaded fuel. The reason why you are advised to do so is because the oxygen sensors are designed to work with higher octane rated fuel like unleaded RON 95/97.

In Nigeria, there are no standards for measuring the fuel you purchase at the petrol station because there is no indication on what you are buying so fuel dealers sell the fuels without any indicated ratings.

In most othercountries of the world, fuel RON (Research Octane Number) ratings are indicated on the pumps at the petrol stations so that you can make the choice for your car.

Using low octane or lead added petrol will sooner or later damage your oxygen sensors and cat as well as possibly ruining your engine. The leaded fuel is that deep red fuel that you will usually only get to see when poured into a container. Unleaded fuel is usually yellowish in colour.

Catalytic converters Don't usually or easily get damaged unless carbon deposits have built up in the catalytic converter to the point of clogging it up and rendering it incapable of carrying out its filteration duties.

It can als get damaged due to excessive temperatures burning it out as raw fuel is deposited into the exhaust system or the honeycomb ceramic structure breaking away.

Raw fuel deposits into the exhaust manifold is mostly caused by faulty injectors, ECU, MAF sensor or oxygen sensors.

If any of these components are faulty, a higher rate of nitrogen oxide emission will be indicated hence the enission related obd codes popping up.

I am an ATA ACCREDITED MASTER TECHNICIAN and I have resolved uncountable issues even in the UK where I had studied, worked andlived for over 16 years before returning to Nigeria. I also owned and operated an auto workshop with a MOT station.

Emission related issues are taken seriously in the UK as well as other developed countries of the world and in the UK we have to ensure that vehicles pass emission tests before a certificate is given. I face these challenges on a daily basis and I think I should be the one who informs you better on what to do.

Always start by scanning and checking the voltage fluctuations on your oxygen sensors. If the voltage readout is ok, check other related components and examine your cat if all else is ok.
Only change a cat when its physically damaged or clogged up with carbon. Washing or cleaning usually restores its functions back but let changing it be your last option as they can be very expensive to purchase while the main problem is still underlying.

Your post is consistent with what I have read on many auto sites. I would like you to shed a bit more light on why the fuel injector cleaner, seemed to solve my P0420 code problem, and also if you may advice on what one can do to protect one's car from harm due to poor fuel quality.

Thereare a numberof thingsthatcouldbe causingthisp0420 catalyst efficiencycode. The mostcommonthingis the catalytic converteritselfis no longer functioningproperly. The other likely thingis the rear O2 (oxygen) sensoris no longer workingproperly. Other thingscouldincludeexhaustleaks,damagedexhaustpipes, damagedO2 sensorwiring/connectors,pluggedcatalyticconverter.
I presently hv dis code now on my vehicle, i hv checked for any exhause leak, i hv changed d O2 sensor twice wit a used one, i hv also use a mobile injector cleaner, all but no avail. I am plannin to use pour a gallon of tiner inside a half fill fuel tank, befor i loose d cat for washin. If all dis fails i will change d cat but it is very very expensive. Not a single tin can cause a P0420. I hv P0136( which is O2 sensor low voltage bank 1 sensor 2) befor i changed d sensor.
I will like the car doctor, jaizetech and nissan parts to comment on dis. My vehicle is toyota sienna 2000 model, but I notice a welded cut underneath d cat wen i buy d car as tokumbo from u.s.a, pls wat must hv cause dat or did dey take out any tin out.

chikasin4: Thereare a numberof thingsthatcouldbe causingthisp0420 catalyst efficiencycode. The mostcommonthingis the catalytic converteritselfis no longer functioningproperly. The other likely thingis the rear O2 (oxygen) sensoris no longer workingproperly. Other thingscouldincludeexhaustleaks,damagedexhaustpipes, damagedO2 sensorwiring/connectors,pluggedcatalyticconverter.
I presently hv dis code now on my vehicle, i hv checked for any exhause leak, i hv changed d O2 sensor twice wit a used one, i hv also use a mobile injector cleaner, all but no avail. I am plannin to use pour a gallon of tiner inside a half fill fuel tank, befor i loose d cat for washin. If all dis fails i will change d cat but it is very very expensive. Not a single tin can cause a P0420. I hv P0136( which is O2 sensor low voltage bank 1 sensor 2) befor i changed d sensor.
I will like the car doctor, jaizetech and nissan parts to comment on dis. My vehicle is toyota sienna 2000 model, but I notice a welded cut underneath d cat wen i buy d car as tokumbo from u.s.a, pls wat must hv cause dat or did dey take out any tin out.

Seems like your cat has been gutted out and I have seen this a lot of times. Remove it and check first.

JaaizTech:
Your post is consistent with what I have read on many auto sites. I would like you to shed a bit more light on why the fuel injector cleaner, seemed to solve my P0420 code problem, and also if you may advice on what one can do to protect one's car from harm due to poor fuel quality.

A P0420 code may throw up if your injector nozzles are clogged up with carbon deposits or residue from excessive use of fake injector cleaners as well as faulty injectors with poor spray pressure.

In your case, it seems more like clogged up injector nozzles delivering poor fuel spray and increasing the nitrogen oxide content of your exhaust emission.

Once the oxygen sensors pick up a high volume of N0x, it will pop up the code and switch your check engine light or mil on.

Obviously, the injector cleaner did the job of de-clogging your nozzles hence the improved performance of the nozzle spray and the catalytic inefficiency codes not coming up. The issue of protecting your car from bad fuel remains a matter of personal concern to any car owner by making sure they buy fuel from reliable filling stations and checking the colour of the fuel.

If its deep red in colour, avoid it as it most likely will be leaded fuel.

Unleaded fuel is usually yellowish in colour. That's what's best for most modern Cars manufactured from the year 1995 onward.

chikasin4: Thereare a numberof thingsthatcouldbe causingthisp0420 catalyst efficiencycode. The mostcommonthingis the catalytic converteritselfis no longer functioningproperly. The other likely thingis the rear O2 (oxygen) sensoris no longer workingproperly. Other thingscouldincludeexhaustleaks,damagedexhaustpipes, damagedO2 sensorwiring/connectors,pluggedcatalyticconverter.
I presently hv dis code now on my vehicle, i hv checked for any exhause leak, i hv changed d O2 sensor twice wit a used one, i hv also use a mobile injector cleaner, all but no avail. I am plannin to use pour a gallon of tiner inside a half fill fuel tank, befor i loose d cat for washin. If all dis fails i will change d cat but it is very very expensive. Not a single tin can cause a P0420. I hv P0136( which is O2 sensor low voltage bank 1 sensor 2) befor i changed d sensor.
I will like the car doctor, jaizetech and nissan parts to comment on dis. My vehicle is toyota sienna 2000 model, but I notice a welded cut underneath d cat wen i buy d car as tokumbo from u.s.a, pls wat must hv cause dat or did dey take out any tin out.

I do feel, if you have noticed a cut on your CAT, you should verify if it has been gutted. If it has been gutted perhaps you should consider putting a defouler between the O2 sensor and the CAT, this may make the code disappear. Sorry, you have to go through all these trouble, it cam be quite frustrating, but when you finally get it, then you realise it is worth the experience.

If I don't use my AC, check engine appear on my dash board. What could be the problem?

Meringe: If I don't use my AC, check engine appear on my dash board. What could be the problem?

Connect a scanner first and see if there r any codes. Also state car make/model etc b4 our resident experts!

flexya:

Connect a scanner first and see if there r any codes. Also state car make/model etc b4 our resident experts!

Toyota sienna 2000 model. I don't have the scanner yet.

Meringe: If I don't use my AC, check engine appear on my dash board. What could be the problem?

Just as Flexya suggested, you need to check the code that is tripping the check engine light with a scanner. If you don't have one ask around for where you can get your check engine light codes checked. Many guys offer this kind of service these days, it shouldn't cost you more than 2000 bucks in a modest mechanic workshop.

That's the way to go... Don't give your car to any rewire to fiddle with...

Lexusgs: PO420 FIX -
I had this codes come up on my Honda S2000 and Celica GT Gen 7. For months I had been reading through all possible solutions online and weighing the cost of having boot catalytic converters replaced.
I read about a carbon clean out system, and thought to gamble on one car first, then if it works carbon clean the other car.
The companies website is www.terraclean.co.uk
I can proudly state that both codes have now been erased from my vehicles ECU after having them terracleaned.
After vehicles were terracleaned, I took off battery, thus allowing ECU to reset itself. Reconnected battery terminal and both codes have been erased. And I have gained all the lost BHP from both vehicles and vehicles acceleration and pick up, I feel has reverted to when the vehicles were near enough new.

https://www.youtube.com/watch?v=E5j6dFFLId0