Hi Stilo owners. Hope all is well.

While under lockdown I've decided to write up a list of 'what to replace' when I go back to work. Due to the worldwide pandemic,work has been put on hold and I'm of the unfortunate lot to not have a pay cheque during this time.

Anyway,O2 sensor downstream is defs on the list because I have a p0141 code and a sluggish acceleration and poor engine performance. Also drop in fuel economy.

While driving today I saw on acceleration that my car has a very light but noticeable smoke when putting my foot down. It's clear or grey-ish in colour. Even when she idles she doesn't smoke but if I rev her then she will kick out some smoke with a heavy fuel smell. It won't smoke continously,only on increase in revs then almost always clears out. Both o2 sensors were covered fully in thick carbon build up upon inspection.
I added piston rings to the list. Am I right in doing so because she does love oil which I read is a trait of the stilos too. Am I looking too far or are the two adding to the poor performance?
She has 230 000 km on clock.
Poor performance
Hesitant acceleration
Feels like shes choking when you rev her. As if she wants to move as the Stilos do but something holding her back. Like she has a heavy ass trailer behind her.
During lockdown I hardly drive her. When I do I'm gentle with her however now and then when I'm out I let her open. Some days she performs really well despite her o2 sensor fault and slow acceleration but some days the problem is more persistent. Hence cannot wait for work hahaha

Would love some advice so i know what to do as soon as work starts again.

Thanks

Post cat o2 sensor heater fault should not cause performance issues on your stilo

jackwhoo said:

Post cat o2 sensor heater fault should not cause performance issues on your stilo

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Thanks for the reply.

What could be the issue then?both sensors were covered in carbon. Alot of it too.

I'm confused when it comes to post CAT sensors,some people say they do contribute somewhat to fuel ratio and others don't.

Oh and as well,
Previous owner removed the CAT converter. The downstream does have a spacer to remove check engine. But now the check engine is on.

NebulaStilo said:

Oh and as well,
Previous owner removed the CAT converter. The downstream does have a spacer to remove check engine. But now the check engine is on.

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I was having deja vue with your posts and see you have posted all of this before in different threads you have started.

No on your car the downstream o2 sensor has no influence on fueling. If you still have the code for down stream o2 heater circuit then of course your car mil light will still be on.

If the number 1 o2 sensor is not reading correctly the ecu cannot properly control the air/ fuel ratio correctly. Even if the car is capable of going into closed loop lambda control.

Are there any cracks or splits in the exhaust manifold or in the exhaust?

jackwhoo said:

I was having deja vue with your posts and see you have posted all of this before in different threads you have started.

No on your car the downstream o2 sensor has no influence on fueling. If you still have the code for down stream o2 heater circuit then of course your car mil light will still be on.

If the number 1 o2 sensor is not reading correctly the ecu cannot properly control the air/ fuel ratio correctly. Even if the car is capable of going into closed loop lambda control.

Are there any cracks or splits in the exhaust manifold or in the exhaust?

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No. There's no leak as far as I can hear and it was done over due to previous owner having a shoddy job done on it. I had the exhaust system welded back properly and securely.

Yes this problem has been coming on for some time. It started out as a erratic idle and then had fuel pump and filter replaced. It worked. To an extent.
Then the sluggish acceleration started. She always drove very well.

Changed plugs,checked spark on all 4 coil packs and they 100%. All plugs are wearing the same more or less.

Some time ago while reversing out my driveway,the box filter for some reason dropped out and cracked rendering it useless. I cannot find one here so I stuck on my brothers old K&N cone filter. Even after having the cone on she drove 100%. Was time after that she started giving issues. Could it be the high volume air intake?
I cleaned the throttle body already.

Here is data from my scan tool. Elm327.

All that data was at idle. No revving. When I rev her abit then o2 sensor 1 reading became more stable. No reading at all from sensor 2. Seems like ecu staying in closed loop

I read all your other threads about this problem.

You should do the same to remind yourself what you have previously posted to keep what you are now posting consistent and accurate.

Are the screenshots you just posted the same ones you posted weeks/months ago ?

Fit a new o2 sensor number 1, do not fit a used sensor,
Only fit the correct o2 sensor for your engine.
Only buy ntk/ngk Or Bosch sensor.

jackwhoo said:

I read all your other threads about this problem.

You should do the same to remind yourself what you have previously posted to keep what you are now posting consistent and accurate.

Are the screenshots you just posted the same ones you posted weeks/months ago ?

Fit a new o2 sensor number 1, do not fit a used sensor,
Only fit the correct o2 sensor for your engine.
Only buy ntk/ngk Or Bosch sensor.

Click to expand...

Yes they are the same.

I have trouble finding sensors for this car.

I work on a part time basis. I'm an audio engineer. This April I was suppose to be extremely busy so I was going to buy the sensor online but now obviously because of the pandemic I cannot.

NebulaStilo said:

Yes they are the same.

I have trouble finding sensors for this car.

I work on a part time basis. I'm an audio engineer. This April I was suppose to be extremely busy so I was going to buy the sensor online but now obviously because of the pandemic I cannot.

Click to expand...

Readings from months ago are of no use at all.

From description of visible smoke in exhaust the engine appears very worn indeed which will result in poor performance.

Check engine breather is not blocked.

Drive the car very gently if you can't afford to replace it.

Find out how to clean the air filter you have and clean it.

The current cv19 virus is badly affecting people all over the world.

jackwhoo said:

Readings from months ago are of no use at all.

From description of visible smoke in exhaust the engine appears very worn indeed which will result in poor performance.

Check engine breather is not blocked.

Drive the car very gently if you can't afford to replace it.

Find out how to clean the air filter you have and clean it.

The current cv19 virus is badly affecting people all over the world.

Click to expand...

Engine breather is clear. I'll clean the air filter,maybe it's blocked up over time hence the eventual slowish acceleration.

Don't know if you saw,when it's cold,like at 2am on way home from work on a winter's night,then she drives and pulles like she use to. When it's normal(not colder than usual) then slow acceleration. Basically hotter the weather,the slower she accelerates.

I am driving her gently and only when its necessary to drive. Otherwise she's standing. I start her occasionally and let her run just to keep her battery up.

Yes I saw that.
Colder are is more dense than hotter air so most car will drive better in colder air than hotter air, that's normal.

You live in a dusty environment the state of the top of the fuse/relay box(which should have a cover over it) shows that, so of course the air filter will get blocked up.

No way Your original air box should not have "Just fallen out of car"
If you have the original air box and it just has a crack on the dirty side of filter element and filter is clean consider refitting . If you can do so without it "falling out" again.

Have you changed the engine oil and filter regularly? Every year at least since you owned car?
How many miles a year does this car drive on average since you have had it.

Have you checked the engine breather since I asked or are you just saying it's fine?

jackwhoo said:

Yes I saw that.
Colder are is more dense than hotter air so most car will drive better in colder air than hotter air, that's normal.

You live in a dusty environment the state of the top of the fuse/relay box(which should have a cover over it) shows that, so of course the air filter will get blocked up.

No way Your original air box should not have "Just fallen out of car"
If you have the original air box and it just has a crack on the dirty side of filter element and filter is clean consider refitting . If you can do so without it "falling out" again.

Have you changed the engine oil and filter regularly? Every year at least since you owned car?
How many miles a year does this car drive on average since you have had it.

Have you checked the engine breather since I asked or are you just saying it's fine?

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I tried salvaging the air box already,it's pretty cracked. The hole is big on the side.

I changed oil and filter last year.
She does 14000km a year on average.

I do live in dusty environment.
I do have a cover that goes over the battery box and fuses. Should there be an additional cover for fuse box in battery box? I never got the car with one.

I have checked the breather. I clean out my throttle body often and inspect the breather

NebulaStilo said:

I tried salvaging the air box already,it's pretty cracked. The hole is big on the side.

I changed oil and filter last year.
She does 14000km a year on average.

I do live in dusty environment.
I do have a cover that goes over the battery box and fuses. Should there be an additional cover for fuse box in battery box? I never got the car with one.

I have checked the breather. I clean out my throttle body often and inspect the breather

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When did you last check engine breather?

How do you check engine breather?

Which brand of spark plugs did you fit?

We're the new spark plugs new our used but new to you?

Has the oil and filter been changed every year?

I can't see your original air box so can't tell from what you say if the hole is dirty air side or clean air side.

Also can't see what fuse cover you have so don't know what you have, the point was it is totally clear you live in dusty environment.

jackwhoo said:

When did you last check engine breather?

How do you check engine breather?

Which brand of spark plugs did you fit?

We're the new spark plugs new our used but new to you?

Has the oil and filter been changed every year?

I can't see your original air box so can't tell from what you say if the hole is dirty air side or clean air side.

Also can't see what fuse cover you have so don't know what you have, the point was it is totally clear you live in dusty environment.

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I check it by removing the pipe and checking if it is free flowing. It's connected just below oil cap.
I checked it few weeks ago.
I got NGK plugs. Brand new from parts store.

Oil and filter replaced every year correct.

NebulaStilo said:

I check it by removing the pipe and checking if it is free flowing. It's connected just below oil cap.
I checked it few weeks ago.
I got NGK plugs. Brand new from parts store.

Oil and filter replaced every year correct.

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Oil and filter changed ever year before you got car?

Ngk are good.

Free flowing between engine and inlet manifold?

jackwhoo said:

Oil and filter changed ever year before you got car?

Ngk are good.

Free flowing between engine and inlet manifold?

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Don't know about previous but I changed it every year since got it.
It's my partners car but we share it and he had the car about a year when we started dating.
I took over care for the car because it was costing to send it away to someone.
I changed oil and plugs and oil filter.

I do plugs also once a year.

He bought the car from a dealer that doesn't exist anymore and they weren't very forthcoming apparently. Crappy dealer tbh.
Clutch was done upon purchase which the dealer paid for.

I don't timing belt last year. My father done it. He has the tools and knowledge to do it. Cam belt was put on correctly.

Yes free flowing.

NebulaStilo said:

Don't know about previous but I changed it every year since got it.
It's my partners car but we share it and he had the car about a year when we started dating.
I took over care for the car because it was costing to send it away to someone.
I changed oil and plugs and oil filter.

I do plugs also once a year.

He bought the car from a dealer that doesn't exist anymore and they weren't very forthcoming apparently. Crappy dealer tbh.
Clutch was done upon purchase which the dealer paid for.

I don't timing belt last year. My father done it. He has the tools and knowledge to do it. Cam belt was put on correctly.

Yes free flowing.

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It sounds like your car was neglected and not serviced correctly before you got it and do is now very worn.

There will be no cheap fix for your car.

Have you found out How to clean the air filter yet? Suspect it has never been cleaned before it even made it to your car.
Is it a genuine k and n filter ?
Or just one that looks like k and n?

jackwhoo said:

It sounds like your car was neglected and not serviced correctly before you got it and do is now very worn.

There will be no cheap fix for your car.

Have you found out How to clean the air filter yet? Suspect it has never been cleaned before it even made it to your car.
Is it a genuine k and n filter ?
Or just one that looks like k and n?

Click to expand...

I found out how to clean the filter thoroughly and it is a genuine K&N. Came sealed in K&N box etc. It was part of a whole K&N induction system.

I had rings and gaskets and bearings priced and not bad despite the car being rare. Cheaper than I thought it would be. Labour ,my father and I can do. I'm going to get hold of 2 NEW sensors too. Upstream and downstream changed. The smaller stuff first before looking inside the engine