Hi everyone 

I read a lot of post by this topic, but I'm writing to talk about mine situation.

It's 1.0 EcoBoost engine and check engine is keep apearing after some miles, I went to dealer to check and they said if it apears again I must replace cat converter and also said that lamdas working fine.

So after this fault apeared again so I changed new cat converter and cleared fault so car can again do self test for this fault by driving cycles.

After a while fault is still pending with new cat, no smoke leaking detekted, puted with new seals. So I am looking for live data on diagnostic and it showing:

Upstream is 1.0V and same on hot

Downstream is 1.6V during warmup and with hot engine it shows from 0.77 to 0.83V at idle.

Maybe anyone can tell me what should be correct readings of lamdas and maybe solution for mine expensive repair to be done? 🙂

Is the upstream not cycling voltage? Is it just stuck at 1v?

Are you using an oscilloscope?

As I know upstream should chandge between 0.2 to 1V but it stay calm 1V to 1.01V. not real oscill. just diagnostic live data.

Ok so after the engine has properly warmed up and holding the rpm at around 2700 rpm the upper sensor should be in closed loop and cycle nicely, normall a high voltage means a rich mixture.

Now your sensor maywell just be dead and stuck in that state, end off story needs replacing.

These are not expensive from ford, alot cheaper that your cat anyway.

Really in this closed loop state you need to be to be checking all other parameters in live data, air temperature,  coolant temperature, does it show closed loop, air pressure anything that looks out of the ordinary. For instance if your coolant sensor is stuck cold it wont go into closed loop.

And i always carry out an emissions test and print a live data screen. Its amazing how much you can learn from these readings.maybe ask your local garage seeing as they cant fix your car.

Obviously check for any air leaks around then engine bay area.

Its very difficult to diagnostic a car from a mobile phone lol and hey i could be on the wrong direction but forums are here for suggestions, so thats what im giving.

This emissions test i pretty important though, as if whats coming out of your exhaust doesnt match your 1v upper sensor reading then it may confirm the fault.

Generally speaking though an oscilloscope is the only way to measure a lamda sensor properly as scanner live data and multi meters are not fast enough to capture all information. Also just to add there are many different type of lambda sensors, eg wideband sensors and some of these work very differently so dont have the same voltage characteristics. 

Goddluck

 

There is readings, upper is changing from 1.0 to 1.02v and not changing its idle or high rpm, system is in closed loop on idle and high rmp.

And downstream is acting crazy from 0.2 to 0.9 as bad cat converter but its new. 🤔

Yes if the engine isnt going into closed loop or there is an air leak that will happen to downstream

If you dont want to diagnose any further and if they are cheap maybe just put an upper sensor on to try, but diagnosis is the best course.

Upto you

Any other sensors are in good range, and as I understand you suggest to find a workshop with exhaust gas analyzer to do emission test to see whats going out of pipe?

Yes get the engine warm, hold at 2700 rpm ish then get a print out of the live readings

Badly but I can't find any workshop with full emission analyzer so all I get from exaust test was lamda 1.V ok and CO is 0.0

Another thing is in parameters:

Short fuel trim is 3.91%

Long is 0.78%

So probably its faulty or leaking injector?

And another problem is new DTC is pending on 2 cyl. missfire sometimes. Maybe its the case? I did fuel system test with diagnostis it showed all 3 injectors without problem so I decided to swap coils with 1 cyl to see tomorrow if it detects miss on 1 cyt so coil would be the case.

If it still says about 2 cyl missfire then band or leaking injector could cause to much fuel and catalystic could not absorb mixture and promt to efficiecy fault.

What do you think guys?

3 minutes ago, Rolandas1 said:

Badly but I can't find any workshop with full emission analyzer so all I get from exaust test was lamda 1.V ok and CO is 0.0

Another thing is in parameters:

Short fuel trim is 3.91%

Long is 0.78%

So probably its faulty or leaking injector?

And another problem is new DTC is pending on 2 cyl. missfire sometimes. Maybe its the case? I did fuel system test with diagnostis it showed all 3 injectors without problem so I decided to swap coils with 1 cyl to see tomorrow if it detects miss on 1 cyt so coil would be the case.

If it still says about 2 cyl missfire then band or leaking injector could cause to much fuel and catalystic could not absorb mixture and promt to efficiecy fault.

What do you think guys?

Also spark plugs is not a case cause I changed all of them about 5000Km ago and only original Ford from dealer.

Any mot station will have a gas analyser, over fueling will also show as hydrocarbons.

Sorry i cant help anymore without physically being there.

Unfortunately in my country its not popular tool, especialy in my area no one have it and tryed surrounding cities, no one needs it they said. 😁 

Of course you cant help much per phone, thanks anyway you told much info for me, I allways was a diesel person but went to petrol so dont know much about them.

Anyway I post there if I get smth new.

No worries