Emissions

[NOVA BUF]

Is there a way of lowering the emissions my car is putting out as it failed on its mot.

[meritlover]

The short answer is yes.

The long answer will require you to put more effort into your question.

[mowgli]

1. what age is the car?
2. what make & model is the car?
3. what engine is fitted to the car?
4. what was the emissions reading??

etc.

[NOVA BUF]

its a h reg Vauxhall nova, it was a 1.0 litre now a 1.2 but have used various different 1.2 Vauxhall nova engines to make this one. but basicly its a 1.2 manual choke carb. I don't know what the failed emission reading was I just know it was high.


Mowgli you may remember this car as you have helped me a few times with getting this car on the road. its my first car and its so nearly there, this is the last thing on the mot failure sheet.

[Stuart]

What was 'high'

Lambda (also needs the high defining as some folks say that more than 1 is high)
HC
etc

[Jack]

H reg won't have a lambda reading will it, as it should be on the old pre-cat test?

[chrisd1986]

H reg won't have a lambda reading will it, as it should be on the old pre-cat test?



tester could of done it wrong

[NOVA BUF]

I don't have any lambda sensors or cat, ive turned the mixture screw to what I think is all the way down, I don't know what reading it gave as it was my dads mate that was doing the mot so he didn't put it through a proper mot on the computer so I don't have an actual failure sheet with the reading on, he just gave me a scrap piece of paper with what needs to be done.

how would the tester have done the wrong test??

[Asa-James]

theres a different emissions test based on the cars age. as yours is older, it would go on the pre-cat test, so have higher limits than the newer test.

[conza123]

at work we put carbed cars on a contiuos test and tweak the carb(s) till emissions are correct then put it threw proper test, and it is reily easy to put it threw wrong test if you not paying attetion because on are boston machine theres so many different options and you can select engine codes etc to

[jimbob-mcgrew]

I wouldn't run the mixture screw all the way in like that, it'll make the engine run lean and hot, could possibly cook it.
check your choke linkage isnt sticking on at all, from the cable motion.
pull the oil breather hose off the airbox, less crap in, less crap out.
check your timings setup right too, that can throw the mixture out if wrong.

how long since it had a service ? oil and air filters
check the state of your plugs too, sooty black is overfueling, and bleached white is overlean. (gives you an idea of whats going on inside)

[mowgli]

Mowgli you may remember this car as you have helped me a few times with getting this car on the road. its my first car and its so nearly there, this is the last thing on the mot failure sheet.

i struggle to remember what i had for breakfast most days..... but make sure the choke is set right, the timing is good & you have bee for a blast to get it warmed up properly beforehand.. if you turn the screw down, count how many times & then wind it back up afterwards.

[meritlover]

how does it compare to last years results if available?
if its jumped considerably, it is unlikely the mixture screw will have moved at all and you will only end up fudgeing a problem which exists somewhere else.

chances are it will be something very simple. Start with doing a basic tune up of ign timing and filters, check the exhaust for holes and joints for leaks.

check your vacuum piping and for air leaks around the carb.

a little more information wouldnt hurt.

even the figures from the test would be nice..........

[NOVA BUF]

thank for all the reply's, they are all much appreciated.

as I said it is my first car and I have not taken it for mot before, I have spent the course of this year building my 1.2 so I do not have previous mot results. and even if I did it would be of the previous 1.0 litre that was in it.

all my timing marks are lining up,
I have done oil and filter including airfilter,
choke is not sticking and seems to be working well.
I don't think there are any air leaks, is there a way of checking this?
now and then the engine runs lumpy so I take the plugs out to clean and they are black and grimey with soot, this is why I turned the screw down to stop putting in so much fuel, am I right in thinking this?

thanks in advance.

[meritlover]

what was reading 'high'? every MOT comes with an emissions print out whether it passes or fails. If you didnt get one, ask for it.

it's not sensible to go randomly tweaking the idle mixture screw. If you speak nicely to the tester, let him try adjusting it on the analyser before he runs another test.