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[olm]

Hello, I take advantage of the topic to comment that for a few days I also have problems with high LTFT. Suddenly I observed an increase in consumption and the LTFT values ​​are over 10-14%. I have checked the vacuum lines and everything seems to be fine, the lambda probes have 45,000 km but it is rare for both to break at the same time. The MAF has about 30,000 km, it seems strange to me that it fails so soon. Any ideas on what to start looking at?

[jandroa]

Hello, I take advantage of the topic to comment that for a few days I also have problems with high LTFT. Suddenly I observed an increase in consumption and the LTFT values ​​are over 10-14%. I have checked the vacuum lines and everything seems to be fine, the lambda probes have 45,000 km but it is rare for both to break at the same time. The MAF has about 30,000 km, it seems strange to me that it fails so soon. Any ideas on what to start looking at?

In my case all vacuum lines seemed to be fine, until the mechanic checked them with a smoke machine, maybe you can check it too the same way.

[jandroa]

We are back to the problem, the errors P0170 and P0173 have appeared again, I will take it to the mechanic to have it checked again. The vacuum leak (loose tube) has already been repaired, since then about 300km have been driven.

[jandroa]

The first lambda sensor will be changed next tuesday, I will post the results after that.

[jandroa]

Long story short - We found a disconnected small tube near the intake manifold that seems to have damaged the lambda sensors and triggered errors P0170 and P0173.

After repairing the leak and replacing one of the lambda sensors (B1), the P0170 and P0173 errors reappeared. A few days ago the second lambda sensor (B2 - precat) was also replaced. Now I am testing the car to see if the problem is solved. Fuel consumption appears to be back to normal.

My mechanic says that a single faulty lambda sensor can trigger both bank errors (P0170 and P0173) and that the MAF has nothing to do with these errors and with both sensors replaced the problem should go away.

[Doctor Gollum]

There's more than one vacuum line. They all do different things but they all come from one source... The inlet manifold.

Hopefully you have found, and fixed, the last of them.

It will take a while for the the sensors to settle down. O2 sensors are pretty robust. If one isn't working correctly then you need to look at the wiring as part of the diagnostic process, but if the readings are out of whack both sides,. that's not coincidence and you might have killed the cats overfuelling it from the vacuum leak or the ECU holding the injectors open (because of the vacuum leaks).

You could replace all four sensors, the injectors, wiring harness and ECU and still have the same problem.

[jandroa]

That makes perfect sense, however I would say the cats are not (too much) damaged, the vehicle recently passed the inspection and had no problems with the emissions test.

[Doctor Gollum]

If the pass grade is 40% of what the cats are capable of, then they can be 60% dead. For example.

That difference might be enough for the sensors to be reading out of the predetermined range hence the error codes.

The fact you have codes both sides suggests a problem common to both sensors... Statistically it's not going to be the sensors.

You could try filling it with Shell V power and taking it for a spirited drive of at least 50 miles just to ensure that everything is properly upto temperature and working as it should.

Pootling around town 10-15 miles at a time will make it worse. Especially this time of year.

[jandroa]

I understand, thank you for the tip!, I will try it as soon as i can.

[jb]

Most likely down to the first small cats on the downpipe failing, try running e5 petrol and if no better just remove the eml bulb as unless you replace both downpipes inc the cats it will continually occur.

[Migv6 le Frog Fan]

Eml light constantly on used to drive me mad. Now I dont really notice it. I just clear the code to put the light off for the MOT once a year. 

[ronnyd]

I use a small piece of insulating tape to turn off.er, hide it on the Vectra. It is off at the moment so it must have been the dodgy rear box. 

[jandroa]

Back to the start, the errors P0170 and P0173 have appeared again after repairing the air leak and changing the two lambda sensors... I will ask the mechanic to change the air filter and clean the MAF sensor, maybe change the fuel filter too, I hope there isn't another hidden leak somewhere.

[TheBoy]

Don't clean Omega MAF sensors, you *WILL* shag them.

[jandroa]

Why? Maybe it is better to change it directly?