Missing o2 sensor

[atifbetani136]

I recently bought a 2003 2od converted to petrol with 1nz fe 1.5. It was giving me about 9 to 10km/litre in the city without a.c.. yesterday I put 15 litre of petrol and it gave me only 115km. I have heard that 1nzfe is suppose to be an economy engine giving at least 12km/l within city .so today I showed my car to an electrition he checked the car and said that this is missing o2 sensor in its exhaust system and said that we have to drill a hole and put a single after market o2 sensor and then wire it to the computer and the fuel mileage problem will be solved.
Has anyone faced this problem I mean how can a car not have o2 sensor in it. Or may be the previous owner changed the engine but kept the same diesel exhaust system.
By the way how many o2 sensors should I buy the electrition said to buy only one but I think 1nzfe engine is suppose to have two.

[capsat]

2D exhaust manifold is different compared to petrol engine 1NZ-Fe engine picture shared is for reference

@Hassan1991 @hasankhurshid29

[Hassan1991]

Yes headers are different. Must have drilled holes to fit 2D headers Share the picture of your car header.
And buy new o2 sensor. Available in scrap yard are already done there work.

[hasankhurshid29]

By the way how many o2 sensors should I buy the electrition said to buy only one but I think 1nzfe engine is suppose to have two.

It only has 1 four wire O2 sensor. Does your check engine light working? Because if no O2 connected the check light should be on.

[UAHMAD]

There are two cat converters and two O2 sensors. One pre -cat/up - stream and the other down - stream sensor.

Before fitting down - stream O2 sensor, I think other variables for improving fuel economy should be taken care of like cleaning throttle body, replacing a clogged up fuel filter, cleaning injectors, replacing spark plugs etc.

[hasankhurshid29]

These are the pictures of O2 sensor on my 1NZ:

[image] - [image] - [image] - [image] This is the 4 wire O2 installed.

[atifbetani136]

[atifbetani136]

Spark plugs are recently changed. Air filter and oil filter is changed. Changed throttle body recently(the spring was broken).
Can't seem to figure out what the problem might be
Am also planning to clean the cat converter when installing the o2 sensor

[atifbetani136]

Well the person how changed the engine also disonected the check light

[atifbetani136]

[atifbetani136]

Check light has been disconnected according to the electrician .

[atifbetani136]

[atifbetani136]

@Xulfiqar
Sir plz shed some light.

[Hassan1991]

Doesn't look like of 1nzfe.
Electrician really don't like check light. Get it connected.

[UAHMAD]

Its precise location.

[atifbetani136]

Yeh i don't see it on the manifold on both passenger side and the driver side . I think the electrician was right.
But still can't understand how the o2 was skipped

[Hassan1991]

No need to understand. This is what our electricians and mechanics do.
O2, Ecu and Injectors are very usually things messed up in swap cars.

[atifbetani136]

Thank you sir
Do you recommend this jugar should I go for it ?

[Hassan1991]

Change the header and install o2. And as member mentioned above new engine have 2 o2 sensors primarily and secondary. 1nzfe and 2nzfe have same sensor. And buy new sensor.

[atifbetani136]

Still a bit confused one is saying there is a single 4 wire sensor and the other is saying there are two mistre is also saying there is one i myself think there should be two so....