Yaris failed nct on low idle CO emmissions

Squatman

What would the cause of this be?

Is it usually the Catalytic converter?
Would a hole in the down pipes ever cause this, or lambda sensors?

Should i get a new exhaust, or should i get a generic cat?

Thanks a million folks,
Regards,
Squatman

Anjobe

Have a look at this for some useful information on the causes of emissions failures.

High CO normally means an excessively rich air fuel mixture (lots of possible causes, including defective lambda sensor), but a defective cat is also possible. You really need to get a mechanic to diagnose this.

An exhaust leak will normally cause a failure for a high lambda reading.

Squatman

Is this something that could be checked/confirmed using a diagnostic tool a la
http://www.ebay.ie/itm/Toyota-Camry-Corolla-Rav4-Yaris-VERSO-Fault-Code-Reader-Scanner-diagnostic-UK-/221110870100?pt=UK_Diagnostic_Tools_Equipment&hash=item337b3c2054

George Dalton

If it passed the high idle and failed on low idle then it is unlikely to be a cat issue.

Can you post up the emissions readings in full as they appear on the report sheet?

Squatman

dont have them to hand, yet, but iirc
low idle CO was 3.1% and high idle was .3 or .5%

hc 414ppm low idle

hc56ppm high idle

Lambda 1.00

Hope this helps

Squatman

high idle could have been 0.06% vol

sumo12

Squatman wrote: »

dont have them to hand, yet, but iirc
low idle CO was 3.1% and high idle was .3 or .5%

hc 414ppm low idle

hc56ppm high idle

Lambda 1.00

Hope this helps

414 HC's LOW IDLE screams high oil consumption. Is there big mileage on the car? Do you have to top up oil regularly? Cat is doing it's best but can't filter all the muck being thrown at it.

Squatman

sumo12 wrote: »

414 HC's LOW IDLE screams high oil consumption. Is there big mileage on the car? Do you have to top up oil regularly? Cat is doing it's best but can't filter all the muck being thrown at it.

Dont have it very long so couldnt say for sure.
There is 148k miles on it, which may be high for a 1 litre.
There is no blowback smoke from the oil cap when running.
Dont know if its an indication, but it ticks over very silently.

galwaytt

I remember the 90's Starlet engines were prone to worn valve guide seals - if compression is good, are Yaris' prone to the same thing ?

nct tester

hc's arent measured on low idle , just co

Squatman

Maybe HC isnt a fail criteria, but it was definitely measured on this test!

nct tester

nct tester wrote: »

hc's arent measured on low idle , just co

According to the results sheets they are measured but there is no acceptance limit and pass/fail is marked as N/A.

Squatman

i just got an obd2 diagnostic plugged into the car, 2 fault codes are showing up.
P0172 and P0172 p , which is "system too rich Bank 1.

The coolant system light is on (for being too cold)
and it failed on low idle CO emissions. can anyone help shed some light on this.
thanks

Bigus

Thermostat stuck open ?

Mar4ix

maybe failed temperature sensor ? ... it cost 10 -15 quid aftermarket one, if it show all time cold to ecu, ecu will make richer mixture, and could be reason of failing emissions on low idle.

not sure it has two sensors or only one..... one for dash, other for ecu.

i think there was possible test that temperature sensor with voltmeter, if set to resistance, on cold should be high figures .. kind of 8000 ohms, and when worm engine, then have to be 2000 ohm. cant remember exact figures, but if you google, will find.

just before check, make sure car engine is cold leave it overnight, and check next day at lunch time, then heat up , check again.

Squatman

Bigus wrote: »

Thermostat stuck open ?

Took out the thermostat, no different

Squatman

Mar4ix wrote: »

maybe failed temperature sensor ? ... it cost 10 -15 quid aftermarket one, if it show all time cold to ecu, ecu will make richer mixture, and could be reason of failing emissions on low idle.

not sure it has two sensors or only one..... one for dash, other for ecu.

i think there was possible test that temperature sensor with voltmeter, if set to resistance, on cold should be high figures .. kind of 8000 ohms, and when worm engine, then have to be 2000 ohm. cant remember exact figures, but if you google, will find.

just before check, make sure car engine is cold leave it overnight, and check next day at lunch time, then heat up , check again.

thats next on the list, should have one by tomorrow, thanks

Bigus

Bigus wrote: »

Thermostat stuck open ?

Squatman wrote: »

Took out the thermostat, no different

If the thermostat was stuck open taking it out would result in no difference

While it was removed did you check was it working?

Squatman

RoverJames wrote: »

If the thermostat was stuck open taking it out would result in no difference

While it was removed did you check was it working?

Didnt think of that actually , but if it was stuck open, it would be circulating and would heat up eventually? also, it wouldnt have the engine managment light on?

Squatman

Squatman wrote: »

Didnt think of that actually , but if it was stuck open, it would be circulating and would heat up eventually? also, it wouldnt have the engine managment light on?

Indeed it would heat up eventually and temp would drop when the air cools the rad contents

I don't think the stat is your issue btw but I was just pointing out the flaw in your logic of removing it given you were possibly thinking it was stuck open as stuck open & removed are much the same thing

Squatman

RoverJames wrote: »

Indeed it would heat up eventually and temp would drop when the air cools the rad contents

I don't think the stat is your issue btw but I was just pointing out the flaw in your logic of removing it given you were possibly thinking it was stuck open as stuck open & removed are much the same thing

yea, i dont think its the problem either, ill try the coolant sensor tomorrow and keep you posted,

Mar4ix

Squatman wrote: »

yea, i dont think its the problem either, ill try the coolant sensor tomorrow and keep you posted,

just as i said you, you need to find out , which sensor show temperature on dash, and which sensor show temperature to ECU, i dont know exactly how is on your car , could be only one sensor, and it is ok.
Usually for dash , there is two wire sensor, and for ecu 1 wire sensor. ... but as i said, i am not sure about you car. need get manual, and have a look.

Squatman

i got a 2 wire sensor from motor factors, but couldnt locate where it would be, found the 1 wire sensor alright, its mounted just above the thermostat, but couldnt find a 2 wire sensor anywhere, there are a few 3 wire sensor alright

Mar4ix

Squatman wrote: »

i got a 2 wire sensor from motor factors, but couldnt locate where it would be, found the 1 wire sensor alright, its mounted just above the thermostat, but couldnt find a 2 wire sensor anywhere, there are a few 3 wire sensor alright

1 wire sensor, thats suppose to inform ecu about temperature, what i am suspect faulty. 2 wire sensor is for dash only, and it suppose to be beside 1 wire sensor, cos, car driver have to see same temperature on dash as ecu.

Squatman

okay, so i replaced the sensor for coolant, and the engine light turned off,
but the coolant light is still on, showing that the car is running cold all the time, also the fan does not turn on! What could be the cause of this?

Mar4ix

Squatman wrote: »

okay, so i replaced the sensor for coolant, and the engine light turned off,
but the coolant light is still on, showing that the car is running cold all the time, also the fan does not turn on! What could be the cause of this?

You said, you removed thermostat. if it was faulty, stuck open, and you removed, there wont be any difference, now , get new thermostat, put it on.
I had lately two cars with stuck open thermostat, in first car i could notice only, when on motorway, temperature drops, other car couldnt heat up ,was driving around a lot and hard, temperature barely got half way up to normal temperature.

Squatman

Mar4ix wrote: »

You said, you removed thermostat. if it was faulty, stuck open, and you removed, there wont be any difference, now , get new thermostat, put it on.
I had lately two cars with stuck open thermostat, in first car i could notice only, when on motorway, temperature drops, other car couldnt heat up ,was driving around a lot and hard, temperature barely got half way up to normal temperature.

yup, i replaced the thermostat, the old one was stuck open, replaced 1 coolant temperature sensor, and have the 2nd one on order, should have by wednesday,
I tested the fan, and it is working, but still seems to be stagnant (water not circulating) perhaps 2nd sensor will fix!

Squatman

Just wondering would a new catalytic converter be the solution to both of these fault codes

P0420 - catalytic system efficiency below threshold
P0172 - Fuel running rich

I replaced thermostat as was stuck open, and both coolant temperature sensors.

biko

Let's keep everything in one thread, it's just better for history.

Is the new cat OEM or generic?

George Dalton

The cat will cure the P0420 code but will not cure the other one.

Squatman

George Dalton wrote: »

The cat will cure the P0420 code but will not cure the other one.

Thats what i thought, I suppose what im asking is, does both fault codes have the same root cause? or am i dealing with two issues?

George Dalton

The reason the cat is not peforming properly is most likely due to the other problem yes. But the cat may already be damaged so even when you fix the cause of the rich running fault code the cat may need to be replaced as well.

Mar4ix

Squatman wrote: »

Thats what i thought, I suppose what im asking is, does both fault codes have the same root cause? or am i dealing with two issues?

before ditch your current cat, maybe look on this video.

if everything is sorted, id advice follow this guy advice, before spend hard earned money.

Mar4ix

Squatman wrote: »

P0172 - Fuel running rich

.

Regarding this problem, ... if you have RIGHT plugs fitted (toyotas are pretty sensitive to plugs, suggest use, what manufacturer recommend) , air filter is new, and correct, suggest read this topic -> http://www.obd-codes.com/p0172

just quick review... could be leaking vacuum line,maybe worth change the all lines, to be on safe side, check fuel pressure,(has to be done properly, and dont think so goin to cost expensive) , and need clean MAF (air sensor) , with maf cleaner. would NOT advise do it with carb cleaner, you may buy maf cleaners, not too expensive (similar to carb cleaner price range), may get in most of motor factors.


EDIT: sorry, has to do way around, first do what i wrote in this post, and after that (if fault still remain) do what that guy in youtube said. you cant break what is already broken, but you may fix