Technical Mot fail - emmissions

[blackydog]

Hi all. 1998 Barchetta has failed MoT on emmissions. The garage have tried several times to get it through to no avail. They aren't keen to keep it in and try and fix it. I'm not sure where to go with it. Sheffield area.
I have ordered a Magneti Marelli Lambda sensor, which the garage have agreed to fit, but with no warranty as they haven't supplied it. They didn't want to be searching round trying to find one, initial searches showed no stock.
I have 8 days left to retest and about the same left on my current MoT.
I have added plenty of fresh fuel, system cleaner and given it a 30 mile blast at motorway speeds.
This is all it has failed on.

 

[bugsymike]

Hi all. 1998 Barchetta has failed MoT on emmissions. The garage have tried several times to get it through to no avail. They aren't keen to keep it in and try and fix it. I'm not sure where to go with it. Sheffield area.
I have ordered a Magneti Marelli Lambda sensor, which the garage have agreed to fit, but with no warranty as they haven't supplied it. They didn't want to be searching round trying to find one, initial searches showed no stock.
I have 8 days left to retest and about the same left on my current MoT.
I have added plenty of fresh fuel, system cleaner and given it a 30 mile blast at motorway speeds.
This is all it has failed on.

Have you been able to read any diagnostics on it like MES etc?
Is it borderline fail or off the clock?

 

[blackydog]

Have you been able to read any diagnostics on it like MES etc?
Is it borderline fail or off the clock?

I haven't tried. Is the software and cable easily available?

 

[bugsymike]

I haven't tried. Is the software and cable easily available?

If you go on Gendans website they supply suitable range of tools and cables as required and if you email them they will advise. You can also browse their site to see what does what you need and prices etc.
There are suppliers of other products online and eBay, but I have had no dealings with them.

 

[s130]

I assume your failure was on CO and/or lambda value? Knowing how it failed the emissions would help. Hopefully not on hydrocarbons as that could be expensive to fix as high HC levels is indicative of oil burning.

 

[Greasytrucker]

I’m sure if you look hard enough you could find an MOT centre that’ll pass it for an extra £10, normally you get the old “We had to put fuel cleaner through it”. Have you got a picture of the emissions failure sheet so we can see how badly it failed?
Obviously if it’s way off then there’s an issue that needs addressing, but if it’s close then in my experience most MOT centres will find a way on a vehicle of that age. My hunch would be they’ll probably pass it with the new Lambda in as they can see you’ve made an effort. Fingers crossed

 

[blackydog]

I assume your failure was on CO and/or lambda value? Knowing how it failed the emissions would help. Hopefully not on hydrocarbons as that could be expensive to fix as high HC levels is indicative of oil burning.

 

[blackydog]

I've changed the oil too now. Didn't think the oil could have any effect, as in theory it's stuck in the sump and galleries but as someone pointed out. Running it at idle (rich) in the cold Winter months (as we do) allows petrol to seep past the rings into the oil, thinning the oil and making it more likely to creep past the rings and being burned. Also ordered an air filter but the old one does look quite clean. Was scratching my head at first when trying to find it

 

[jackwhoo]

You will absolutely have to connect to engine ecu and see if sensor readings are realistic ie engine temp realistic etc
If all look sensible you will need a new catalyst
Emission sheet readings not bad , hc very low which good

 

[blackydog]

You will absolutely have to connect to engine ecu and see if sensor readings are realistic ie engine temp realistic etc
If all look sensible you will need a new catalyst
Emission sheet readings not bad , hc very low which good

If I'm reading it right, it is the Lambda reading which is too high and the carbon monoxide level? If what I have done already plus the new Lambda sensor don't fix it, I will invest in the Gendan software.

 

[jackwhoo]

No the failure was co to high at idle.

 

[jackwhoo]

Get current o2 sensor back when new one fitted in case

 

[blackydog]

Get current o2 sensor back when new one fitted in case

Is that the Lambda sensor?

 

[blackydog]

No the failure was co to high at idle.

Any idea what is a likely cause of that?

 

[jackwhoo]

Is that the Lambda sensor?

Yes lambda sensor = O2 sensor

 

[jackwhoo]

Any idea what is a likely cause of that?

Many potential things see post number 9 how to move forward

 

[s130]

See here: https://www.smogtips.com/failed-high-carbon-monoxide-CO.cfm

Certainly check / replace the air filter.

You pass at high RPM where the engine will generate more suck / air flow which weakens the mixture even with a clogged filter. Ith a clogged filter then at idle the ECU may be compensating for lower air flow by demanding more fuel which will increase the CO.

Your garage will probably be happy to just test the idle CO (takes next to no time) for free after you have changed the O2/lambda sensor and change the air filter.

 

[bugsymike]

What was the engine temp during the test, often you can drive the vehicle to test after a good blast fully warmed up , then it lingers around getting cold before they get around to your vehicle and they put through it through the test it's not at optimum, ideally it needs to be 80 degrees Centigrade at least for the Lambda "Closed loop test".
"The "CLOSED LOOP" status is signalling that the control unit is using the Lamda sensor signals to calculate the A/F mixture (normal status when operating temperature has been reached)." so if engine too cold readings will be bad, incidentally even a tiny exhaust leak can affect results.

 

[blackydog]

Passed today but very borderline. Changed the oil and plugs, air filter still hasn't been delivered (the current one is very clean). New Lambda sensor ordered from Autodoc and it had the wrong plug on, so had to be joined. Mine has the yellow square plug but the one I ordered came with an inline black plug.

 

[bugsymike]

Passed today but very borderline. Changed the oil and plugs, air filter still hasn't been delivered (the current one is very clean). New Lambda sensor ordered from Autodoc and it had the wrong plug on, so had to be joined. Mine has the yellow square plug but the one I ordered came with an inline black plug.

Still it gives you twelve months to investigate.