Car failed MOT on emissions!!!

[_Alex_D_]

What do I have to do to fix it?

Fast idle test:

RPM 2645 Pass
CO Max limit 0.300 Actual value 7.434 Fail
HC Max limit 200 Actual value 389 Fail
Lambda Min Limit 0.970 Max Limit 1.030 Actual 0.794 Fail

Second fast idle test:

RPM 2772 Pass
CO Max limit 0.300 Actual value 2772 Fail
HC Max limit 200 Actual value 364 Fail
Lambda Min Limit 0.970 Max Limit 1.030 Actual 0.796 Fail

Natural Idle test

RPM 813 Pass
CO Max limit 0.500 Actual value 8.489 Fail


Is it the upstream lambda sensor thats faulty? If so how much?

Also failed on:

nearside front wheel bearing has excessive play.



Any help much appreciated!

 

[davebem]

When was your 172 registered? 90% of them have just 1 downstream lambda sensor, the later ones had both. Does it have the standard cat? Did you take if for a good drive before the test?

 

[Andyman]

Stuff a rag inside the exhaust. As long as it dosent go on fire it'll pass :rasp:

 

[_Alex_D_]

It's 2001 ph1. Thing is it's been sat for a week but I did have a problem with it miss firing last week and had to take plugs out clean them and put em back in. When I cleared the engine management light it showed 512 destructive miss fire and up stream lambda sensor. Auto electricion said lambda could of been showing cause of miss fire.

 

[_Alex_D_]

How much would a sensor be?

 

[caister]

My 2001 PH1 has two sensors so yours probably does too i think they are quite expensive

 

[Neal 182]

Has it still got a misfire as that a high reading even with a lambda fault could still be a lambda fault throw and this the car running alright

 

[_Alex_D_]

Runs fine now. Do you think it might worth changing plugs and lambda?

 

[Fred@BTM]

£45 for plugs, £90 odd for a genuine lambda

 

[Mark One]

I got an NKG lambda for my MK1. was DEFINITELY the best thing I ever did. I swear to keep all my lambdas mint for as long as i drive

 

[stu-172]

Get a universal 4 wire lambda they aren't that dear £20 should get you 1!

 

[Jay Payne]

Mine was reading way high on the emissions test
. I got it hot/ragged it to the test centre too.

The tester just held it at 4000rpm untill it dropped.took bloody ages and i was getting worried. then he let the machine do the test by running at 3000rpm

 

[davebem]

Are the universal lambdas any good. It is suprising how much difference they make, especially for the cars that have 2 sensors.

 

[mattjk]

the second sensor doesnt do anything anyway does it? Mine post cat lambda is not plugged in

 

[stu-172]

Are the universal lambdas any good. It is suprising how much difference they make, especially for the cars that have 2 sensors.

I bought 1 and have had no problems with it! Bought off ebay for 13 quid or something daft!

 

[BSC 182]

The voltage reading from the lambda sensor is often a very good place to start with your diagnose of an emissions failure fault. The lambda sensor can be used as a pre-cat emission tester when used with either an accurate voltmeter or an oscilloscope. With the engine up-to normal working temperature, check the output of the sensor wire, normally black with Zirconia sensors, you should expect an output of 0.2 – 0.8 volts fluctuating between these reading approximately 2 – 3 times per second. If the output voltage is lower than this, i.e. 0 – 0.2 volts there will be a lean running or excess oxygen problem. If the voltage is higher than this, i.e. 0.8 – 1.2 volts then there will be a rich running or excess fuel fault.

 

[_Alex_D_]

Turned out to be MAP sensor. Was running way rich. He pulled sensor out and stuck his finger over hole and it sounded better straight away. Bloody engine diagnostic cost me £73 though. It's passed now but god if I'd of known what it was I'd be £73 better off. Only took him 15 mins as well

 

[Neal 182]

Yes but it could of cost you £90 odd for a genuine lambda and then you would of tryed the Plug's at around £40 so you have saved money at the end of the day

 

[_Alex_D_]

Thats true neal. Genuine Lambda £102 and £109 (there are two)