smiffyraf1
New member
Hi guys had my overdue MOT done today but failed on emissions in that carbon monoxide was too high. ive chucked some fuel/injector cleaner in but could i be possible looking at an engine rebuild here? 
MOT failure
- Thread starter smiffyraf1
- Start date
MGBV8
New member
Did it fail by a lot or a little?
If your car is fitted with a cat and it only just failed, give it a really good roast down the motorway and burn some of the crud off.
You can also do an oil change that will help a little.
Other things to try are new air filter and new lambda sensor.
A bit of basic maintainence should see you right.
If your car is fitted with a cat and it only just failed, give it a really good roast down the motorway and burn some of the crud off.
You can also do an oil change that will help a little.
Other things to try are new air filter and new lambda sensor.
A bit of basic maintainence should see you right.
Fat Albert
New member
I had a Saab Turbo fail as it was over-fuelling and somehow mixing fuel with the oil that was then coming back up the breather...new lambda fixed the over-fuelling and then it needed an oil change to sort it
robwright
New member
I don't think your car has a lambda sensor mate. Worse case scenario I think maybe a new air flow meter. I wonder if elliot may even have one for an S that you can borrow for the MOT. They aren't too hard to change. You haven't done anyhting since your last MOT so it must be down to component wear/age. As there is very little or in fact nothing you can tune on a fuel injected sytem as said I would forst of all service it if not done recently including the fuel filter and air filter or maybe even take the air filter out round the corner from MOT station [] My money would be on air flow meter. Trust me it has a big effect on idle mixture. One of the benefits of having an AFR meter. And yes as said a good Italian tune up on the way to the MOT station.
] My money would be on air flow meter. Trust me it has a big effect on idle mixture. One of the benefits of having an AFR meter. And yes as said a good Italian tune up on the way to the MOT station.
andy watson
Moderator
As Rob says +1 for the AFM
Although I don't believe you will want one for an S after Sunday when the truth came out[][][]
Although I don't believe you will want one for an S after Sunday when the truth came out[
][][]
delboy1974del
New member
blast it in low gears first off and burn off any carbon on your pistons
Sensible questions:
1. How much did it fail by? What was the reading?
2. Was the engine hot when the test was done? Hot = running for at least 20 minutes before the probe as put in.
3. Have you driven the car fairly long and hard in the last week?
4. When was it last serviced? What state are the plugs, leads and rotor arm in?
An engine rebuild is very unlikely to be necessary - rest assured. But some other, more basic work may be in order. Service it, change the air filter and plugs, think about changing the leads, and give it a very, very good long and hard thrash, then take it into the MOT centre nice and hot, and you are likely to pass.
Keep us posted.
Oli.
1. How much did it fail by? What was the reading?
2. Was the engine hot when the test was done? Hot = running for at least 20 minutes before the probe as put in.
3. Have you driven the car fairly long and hard in the last week?
4. When was it last serviced? What state are the plugs, leads and rotor arm in?
An engine rebuild is very unlikely to be necessary - rest assured. But some other, more basic work may be in order. Service it, change the air filter and plugs, think about changing the leads, and give it a very, very good long and hard thrash, then take it into the MOT centre nice and hot, and you are likely to pass.
Keep us posted.
Oli.
Copperman05
New member
If you are just over in emissions, a slight adjustment of engine idle can get a pass.
Ask me how I know[].
Edd
Ask me how I know[
].Edd
smiffyraf1
New member
failed by a lot, just had a new air filter, dizzy and rotor, ht leads and plugs will do an oil change as was due that anyway. i dont know if they tested it hot, i doubt it. it is not my usual MOT centre and havent been that impressed with them going for retest elsewhere.
James, (why is everyone on this board called James, Nick or Paul?)
OK, it needs to be tested hot - cars use large amounts of fuel when warming up, and that is reflected in a huge increase in exhaust emissions. When hot they use less fuel and emissions drop off steeply. If it wasn't tested hot then it needs to be.
A duff AFM will have a big impact on emissions as well. And is a possible suspect. Having said that, the AFM used on the S2 can be adjusted for richer or leaner running, and I suspect the same applies to your lux. Did the garage try adjusting it at all?
Here's a suggestion. Take the car for a decently hard drive, and come home via an MOT place. Ask them if they will test only the emissions - most places will do this for a fiver. If the reading is low enough to pass an MOT then either ask them to go ahead and do a full MOT, or book a full test and make sure the car is hot when it is taken in for it. If it is too high to pass an MOT, and the garage can't adjust it lower, then look into buying a replacement AFM.
Oli.
OK, it needs to be tested hot - cars use large amounts of fuel when warming up, and that is reflected in a huge increase in exhaust emissions. When hot they use less fuel and emissions drop off steeply. If it wasn't tested hot then it needs to be.
A duff AFM will have a big impact on emissions as well. And is a possible suspect. Having said that, the AFM used on the S2 can be adjusted for richer or leaner running, and I suspect the same applies to your lux. Did the garage try adjusting it at all?
Here's a suggestion. Take the car for a decently hard drive, and come home via an MOT place. Ask them if they will test only the emissions - most places will do this for a fiver. If the reading is low enough to pass an MOT then either ask them to go ahead and do a full MOT, or book a full test and make sure the car is hot when it is taken in for it. If it is too high to pass an MOT, and the garage can't adjust it lower, then look into buying a replacement AFM.
Oli.
smiffyraf1
New member
thanks for that sounds a good idea. ill give elliot a shout see if hes got any knocking about as am sure the afm is probably due replacing anyway.
It won't be needing a rebuild I can tell you that much - my engine which did need a rebuild was using about 1 litre of oil for every 300 odd miles - the piston rings were completely shot (as anyone at the Rolling Road day near Neston a few years ago will remember) and it STILL passed its MOT on emissions! The AFM has been a reasonably regualr failure the last few years on this forums I've seen, I don't think it can be fixed diy but can be proven to be the problem diy, which at least is 90% of the work []
]
smiffyraf1
New member
update: passed its test in the end. nothing needed for emissions just dont think they had warmed it up enough, needed some welding on the frame where the rear suspension hinges from. happy daze
Fat Albert
New member
Phew! My SAAB cost me over £400 in the end!
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