Mot emission fail

S

spall12

Member
Hi guys

Just got car back from the mot station and it has failed on emissions.

It failed at the lambda on both tests.

Test sheet says it should be between .97-1.03 but 1st test came back at 1.06.

2nd test came back at 1.05.

The car was left at the garage the night before the test then mot done 1st thing in the morning. Any ideas on what I need to do to get car to pass. Was thinking of using cat clean and a long drive before the retest ?
 
I always take it for a blast and make sure its fully warmed up , always works for me, tbh got a few mates with old Z3's and they tend to do the same,
Good luck
Maurice
 
Put in a can of the cleaner as you suggest and take it for a 20 minute blast before getting it MOT'd. Incidentally has the air filter been changed recently, if not its only cheap and could make a big difference.
 
Maf or lamba sensor is usual suspect.
Maf cleaner is cheap.
Can of decent fuel additive is cheap also.

If there is still an issue then maybe a faulty lamba
 
Worth reading the fault memory, would expect faulty lambdas to show up. Can get a cable and software for around £30 which is cheaper than paying people to do it for you.
 
As above, cheap possible fix would be a bottle or two of fuel additive/cleaner and a good half hour warm up/run before turning up for test appointment.
 
maxman said:
ive put new lambdas new maf fuel additive still failed help!!!!!!
Click to expand...

Was it nice and hot for the test?
Worth checking the fuel trims. They can be a good indicator of sensor problems. Overfueling will often cause emisions failiure.
 
Could it be down to fuel. Do you use the cheaper supermarket variety, in which case some nice premium fuel might help. Also check air filter as I mentioned previously and spark plug condition. If they havent been changed in recent years pop in a new set. Then give car a good 20/30 minute drive before another test.
 
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