Emissions very high!!

[AlfaJack]

Hi all,

I have had my cars yearly MOT test and the emmisions test is failing badly!

The CO is reading at 3% - the maximum it should read is 0.3%!

First thing I will check is the lambda, but I also want to check the water temp sensor.

Do you have any tips on how to do these, A member on alfa155.org told me to measure the lambda in ohms, and if it is above 4 ohms then replace it

but I have also read that I can measure the voltage of it when at 2000rpm, I will try this tonight.

Does anyone know the resistance of the water temp sensor when working?

Also, does a series 1 Q4 have a CO adjuster in the engine bay, anyone have a pic of it?

Thanks for your help,

Jack

[arjunior45]

Also, does a series 1 Q4 have a CO adjuster, anyone have a pic of it?

Thanks for your help,

Jack

the CO pontesiometer {adjuster} for all the series is located in the enginebay on the firewall on the left side near the steering fluid tank.
If you open the hood and look in the bay,it is on your left next - close to the MAP sensor.A little grey thing, there's a small dust cap covering the potentiometer itself.
Check first if this is set to 0.2% and then check the lambda sensor or anything else.
Cheers
Nick

[AlfaJack]

Check first if this is set to 0.2% and then check the lambda sensor

Thanks Nick, I will be doing this tonight, how will I know when it is at 0.2 - I think its just a screw in or out? I am guessing I screw it all the way in, hopfully it is documented in the manual

[arjunior45]

Check first if this is set to 0.2% and then check the lambda sensor

Thanks Nick, I will be doing this tonight, how will I know when it is at 0.2 - I think its just a screw in or out? I am guessing I screw it all the way in, hopfully it is documented in the manual

Yes, it a screw in or out but I think you'll need a professional gas analyzer-meter {like the one they have in MOT or in the garages - at least that's the meter we use} that indicate the CO, HC, CO2, lambda ... and see what happen when you unscrew or screw this potensiometer.
I do not know if anything is mentioned to the manual and I do not have the manuals with me right now, but Steeve has all the manuals in his site {www.alfarchive.co.uk}.
If I'll have some free time I'll look at them, but it is very difficult right now.

Cheers

Nick

[AlfaJack]

Thanks Nick,

Iv tested tje lambda and it seems its stuck at about 0.28 - broken I believe

Im going to try the one from the other car and see if thats much different.
Getting the old one off is a mission - its prettty much welded on, having to remove fan to get any kind of movement.

btw, I also noticed that the tail pipe is very dark and sooty, and there was some fluid sitting in it - not sure if its unburnt fuel or water.

The low (almost static) voltage of the lambda would suggest that the car is running lean, despite the above?

Any one shed any light?

[arjunior45]

Thanks Nick,

Iv tested tje lambda and it seems its stuck at about 0.28 - broken I believe

Im going to try the one from the other car and see if thats much different.
Getting the old one off is a mission - its prettty much welded on, having to remove fan to get any kind of movement.

btw, I also noticed that the tail pipe is very dark and sooty, and there was some fluid sitting in it - not sure if its unburnt fuel or water.

The low (almost static) voltage of the lambda would suggest that the car is running lean, despite the above?

Any one shed any light?

dark and sooty tail pipe is something to expect if the car is running in rich fuel for some time. Do not wory about that.
As for the liquid sitting there I believe that it is water - fuel-gas evaporate very quickly and you can not see it! But you could test that when the engine is running. Just close the end of the pipe with the pulm of your hand for few seconds and then smell it. By the odor you could say if is fuel or water!

For the voltage of the lambda sensor do not expect high voltages.
The "normal" lambda sensor works from 0 volt up to 1 volt, with intervals of 0.1 volt. The ecu-I.A.W. "understand" as lean fuel the 0.2 volts and as rich fuel the 0.8 volt. So, if you get 0.28-0.3 volt from that sensor and you have 30% of CO might indicate that the sensor is off.
Only the "wide band oxygen sensor" works from 0 up to 5 volts! And the correct-best value are the 2.14 volts - or very close to that, I do not remember the exact value. But "wide band oxygen sensor - wide band lambda sensor" is used only during the engine tune-up, in order to find the proper fueling, and not only, in the map of the I.A.W.

Cheers

Nick.

[AlfaJack]

Nick thanks again, You say the sensor may be "off" so I guess the ECU is overriding its readings and running it rich and causing my 3% CO

I have taken the lambda from my project car I tried to fit it but I cant get the faulty lambda off, its like its welded on to the manifold, I am removing the fan so that I can get some movement on the spanner - its so very tight though but these things are to be expected.

Thanks
Jack

[arjunior45]

Nick thanks again, You say the sensor may be "off" so I guess the ECU is overriding its readings and running it rich and causing my 3% CO

I have taken the lambda from my project car I tried to fit it but I cant get the faulty lambda off, its like its welded on to the manifold, I am removing the fan so that I can get some movement on the spanner - its so very tight though but these things are to be expected.

Thanks
Jack

yes, if the max ridding of your lambda sensor is 0.28 volt, the ecu-I.A.W. probably takes the 0.28volt as 0.2volt {too poor fuel} and "send" more fuel to the injectors, or as 0.3volt which is the lowest limit.
Hope you'll manage to take off the lambda from your car.
Let us know how the thinks are going.
Cheers
Nick

[AlfaJack]

Yep the lambda feels pretty much welded on - have taken the fan out and tried as hard as possible with all sorts of leverages to get the lambda off but it wont shift.

I am going to try and take the short pipe off - the one that the lambda is actually in. It appears to have 3 bolts at the turbo end, and 4 bolts where it goes in to the rest of the downpipe.

The 4 bolts to the downpipe seem ok, but at the turbo end it appears a little more difficult - there is one bolt round the back, I havent tried yet, but does anyone know if there is enough space to get a socket in the gap to undo it?

Thanks

[Steve Webb]

I am going to try and take the short pipe off - the one that the lambda is actually in. It appears to have 3 bolts at the turbo end, and 4 bolts where it goes in to the rest of the downpipe.

The 4 bolts to the downpipe seem ok, but at the turbo end it appears a little more difficult - there is one bolt round the back, I havent tried yet, but does anyone know if there is enough space to get a socket in the gap to undo it?

Thanks

The turbo elbow car be a bugger to get off as well, the turbo end of things isn't too bad, but the last time I split the downpipe from the elbow, 2 of the studs in the elbow sheared off !!!!!

Have you tried heating the elbow up with a blowtorch before trying to undo the lambda?

Steve

[AlfaJack]

I am going to try and take the short pipe off - the one that the lambda is actually in. It appears to have 3 bolts at the turbo end, and 4 bolts where it goes in to the rest of the downpipe.

The 4 bolts to the downpipe seem ok, but at the turbo end it appears a little more difficult - there is one bolt round the back, I havent tried yet, but does anyone know if there is enough space to get a socket in the gap to undo it?

Thanks

The turbo elbow car be a bugger to get off as well, the turbo end of things isn't too bad, but the last time I split the downpipe from the elbow, 2 of the studs in the elbow sheared off !!!!!

Have you tried heating the elbow up with a blowtorch before trying to undo the lambda?

Steve

Havent tried heating yet although it has crossed our minds to. We thought to make enough of a difference to a manifold we may need something bigger than a normal blow torch - I think oxyacetylene (not that I have it) would cut through the manifold all together!

I dont want to shear anything so will put a bit of heat on it tonight. Other thing I thought of was to break the lambda in half and put a socket and extension over it and use a big breaker bar - still not garunteed to shift though!

[Steve Webb]

Just a thought, but if you are sure the lambda is screwed and don't mind destroying it, is to chop the top part off, then drill a hole straight through it, into the exhaust elbow. Now when you start trying to unbolt it, it can compress a little (because of the hole) and should loosen abit easier.

[AlfaJack]

Yup, thats another option - kind of dont want to get too much rubbish in the exhaust.

Im not certain its broken so I was going to try the lambda from the other car before I open the new one etc, but il just have to bite the bullet!

[AlfaJack]

It was sooo stuck in there, I think this may just be why:



I think it was put in using a hammer - needless to say the manifold needs re-tapping - lets hope the local auto shop will lend me one - thats if he even has one that big :shock:

[arjunior45]

Hope that this will end your problem.
Let us know how goes with the "new" lambda sensor

Cheers
Nick

[Juan AR155Q4]

Seems I saw very late this thread...
If you weren't sure about the misfunction of the lambda probe, you would have to test the 12V for the heating of the probe. I have had that problem. No 12v for heating and lambda was stuck in 0.3v.

[AlfaJack]

Seems I saw very late this thread...
If you weren't sure about the misfunction of the lambda probe, you would have to test the 12V for the heating of the probe. I have had that problem. No 12v for heating and lambda was stuck in 0.3v.

Hi Juan,

Should the two white wires have a permanent 12v?

If it doesnt does that mean my lambda could be ok when 12v is restored?

What caused the 12v to fail?

Cheers

[Juan AR155Q4]

Lambda probe heater works the same as fuel pump. You shuold have 12v for a couple of seconds when put the car in contact. Then it's off. When the engine it's running, you should have peramently 12v.
My problem was a corroed conector. Check conectors and relay from fuel pump (near brake fluid reservoir, fuse 15 A of fuel pump).

[AlfaJack]

Lambda probe heater works the same as fuel pump. You shuold have 12v for a couple of seconds when put the car in contact. Then it's off. When the engine it's running, you should have peramently 12v.
My problem was a corroed conector. Check conectors and relay from fuel pump (near brake fluid reservoir, fuse 15 A of fuel pump).

I tested and it has 12V permanently.

Re-tapped the thread (nice engineer guy who I never met before lent it to me for free ) fitted new sensor - and its still just as bad - got an emmisions test done free before they logged in for the MOT test thank god!

The CO seems to go from 3% down to 0.8 and then back up again at 3K revs,

the new lambdas voltage seemed the fluctuate when I fitted it but when I tested it after the emisions test i wasnt really moving from 0.45


Time for me to give up and hand it over to the specialist - Gonella Brothers in Catford so they can charge the earth and make my overdraft 9 times bigger than it already is :evil: :evil: :evil: :evil:

[FletchQ4]

im sure my mech said they have to be re set when the sensor has been replaced.
he re set mine on the twinny when it was on its way out but said it wouldnt last.

[AlfaJack]

Still it is failing.

The mechanic says, no air leaks, cats are fine, the CO adjuster is correct.

He suspects the new lambda could be the wrong one, its a bosch part, No. 0258003957

However the part number on the lambda of my other Q4 is different, I think it ends in 061 (its Bosch too) - I have dropped this one off at the garage for him to test.

If at all possible and someone has a lambda lying around could you tell me the number on it.

Thanks

[Juan AR155Q4]

Tonight at home I´ll post numbers cause I have a couple.
In the meantime try this: put the heater direct from battery (the whites ones). You´re having the same problem I had.

[AlfaJack]

Tonight at home I´ll post numbers cause I have a couple.
In the meantime try this: put the heater direct from battery (the whites ones). You´re having the same problem I had.

Hi Juan, many thanks, I forgot to say, I tested for 12V and it was fine, hopefully the garage will call soon

[Juan AR155Q4]

Hi Juan, many thanks, I forgot to say, I tested for 12V and it was fine, hopefully the garage will call soon

Did you measure voltage between the white wires or did you put a pair of extra wires directly from batery to lambda probe?

[AlfaJack]

Hi Juan, many thanks, I forgot to say, I tested for 12V and it was fine, hopefully the garage will call soon

Did you measure voltage between the white wires or did you put a pair of extra wires directly from batery to lambda probe?

I measured the voltage between the two white wires, I will suggest this to the mechanic although I assume he knows this already