what are the vechile CO limits????

[disco-v8]

ok ive been trying to found the CO limits for my car, and all i keep coming up with is a thing stating after 1992 BLAH BLAH BLAH..........

im sure that every vehicle has its own set vehicle emissions, stated in the constuction and use for that own vehicle...... and i just cant find it any where, like im sure my 3.9 V8 has a differnt CO limit than to my 1.8 Xsara

like how does a garge no the limits to my vehicle, he must have it writen down somewhere????


hope somebody knows what im trying to say lol

[Highlander1]

Hope this helps from my memory vehicles first used before Aug 1979 WOULD FAIL IF

1 A emits dense blue or clearly visible smoke,or clearly black smoke for a period of 5 seconds at idle.

2 B emits dense blue or clearly visible black smoke during acceleration which would obscure the view of other road users.

Older vehicles pre 1960 sometimes emit unavoidalbe smoke due to design such is not a reason for rejection.

Engine must be at operative temp of 60  0c and engine must be purged for 20 seconds at around 2500 rpm before commencement of test.

That takes care of older diesels. for smoke.

Now any DIELSEL vehicle from 1Aug 79 till present when checked for emmisions once at operating temp is reached you only have one chance it's a blip of the throttle till a reading is obtained but be 2.5% or less for normal diesel. 3% for turbos.


If your MOT man's a bit fair he may choose to allow you to purge as before, before inserting probe.

On spark ignition vehicles (not diesels) it's worth noting that vehicles uncapable of passing the test at manufacturing stage will be exempt, but owner must produce supporting evidence manufacturers data sheets etc.

You must pass both tests 1 for hydro carbons and one for co emissions.

If vehicle has 2 exhaust pipes readings are taken from both an them average figure obtained.

Any exess should be apparent for minimum of 5 seconds.

Ok  for vehicles pre 1975 visual inspection only is required. For 1st Aug 1975 till 1986 co percentage to pass must be 4.5% or below. Hydro carbons 1200ppm.

Next if used after 1 Aug 1986 then emissions are 3.5% hydro carbons are same.

Now for catalytic convertors fitted from 1996 till present the emission test is  between 0.97% and 1.03%

If you present a car 1997 with no cat the test cannot be performed and will be refused.

The Cat in some grey imports are later after 1996 and have no cat fitted so beware.


Cheers hope thins helps any porblems send me a message.

Regards H1

[disco-v8]

thats the same sort of stuff i keep reading, so doesnt realy help me....


im sure that a 3.5 V8 will have different CO limits than my 3.9 V8 and they are both after 1979.... plus my 3.9 has cats but is only a 1994, but i bet if i took these off it wud fail the CO limit even tho it doesnt need them...

can you see my point!!!!

[muddysteve]

The co2 limit as far as mots go is the same for all

so a 1l mini can be running like a bag of spanners and still be under the 3.5% but a 4.0 v8 will have to be running sweet to get the same results

[hairyasswelder]

Sometimes there is a sticker under the bonnet for max.
I have autodata on laptop and will look later (if I remember) and see if that gives it  :D

CO2 limit for tuning purposes not mot  :?:

Steve

[hairyasswelder]

Auto data says> Discovery 3.9 90-98
CO Level at idle speed - tailpipe  vol% CO : 0.5 max not adjustable
HC level at idle speed - ppm 100
CO2 level at idle speed - vol %CO2 14.5-16
o2 level at idle speed - vol % o2 0.1 - 0.5
Increased idle speed for CO test rpm 2500-2800
CO content @ increased idle speed vol % 0.3
lambda at increased idle  - 0.98-1.02


Hope this is what you meant  8)

Steve

[disco-v8]

Auto data says> Discovery 3.9 90-98
CO Level at idle speed - tailpipe  vol% CO : 0.5 max not adjustable
HC level at idle speed - ppm 100
CO2 level at idle speed - vol %CO2 14.5-16
o2 level at idle speed - vol % o2 0.1 - 0.5
Increased idle speed for CO test rpm 2500-2800
CO content @ increased idle speed vol % 0.3
lambda at increased idle  - 0.98-1.02


Hope this is what you meant  8)

Steve

that is exsactly wot i was after... brilliant thanks for that...

so i take it its differnet for every car then????

any chance you could also put the data for the 3.5 efi and the 4.0 & 4.6 that would be even better

[ian_s]

the limits in the MOT are a percentage of the total exhaust.
the bigger the engine, the more exhaust gases come out, the more co2 you can produce to pass the MOT

[Sider]

The CO2 varies between engine. The CO, and correct me if I am wrong, is the produce of bad combustion, and as such, not really predetermined by the  size of the engine.  

Limits are, if memory serves:

If vehicle first used before 1st August 1975: visual smoke test only

If vehicle first used before 1st August 1986: max 4.5% CO

If vehicle first used before 1st August 1992: max3.5% CO, unless fitted with a catalyst, in which case it is 0.5%

If vehicle first used on or after  1st August 1995: Max 0.5% CO

[McGuire]

Note that the year of manufacture of the engine also applies. If a '75 engine is fitted to a '99 car, the values applicable to a '75 engine apply. And a cat is not needed if the original engine did not have one. Year of manufacture of the vehicle in this instance is irrelevant.
 It is down to the owner/driver to prove the engine year to the tester, normally with a letter from the engine manufacturer confirming.
http://www.motuk.co.uk/manual_730.htm

[hairyasswelder]

Auto data says> Discovery 3.9 90-98
CO Level at idle speed - tailpipe  vol% CO : 0.5 max not adjustable
HC level at idle speed - ppm 100
CO2 level at idle speed - vol %CO2 14.5-16
o2 level at idle speed - vol % o2 0.1 - 0.5
Increased idle speed for CO test rpm 2500-2800
CO content @ increased idle speed vol % 0.3
lambda at increased idle  - 0.98-1.02


Hope this is what you meant  8)

Steve

that is exsactly wot i was after... brilliant thanks for that...

so i take it its differnet for every car then????

any chance you could also put the data for the 3.5 efi and the 4.0 & 4.6 that would be even better

4.0 & 4.6 are giving the same results
but 3.5 efi is

CO Level at idle speed - tailpipe  vol% CO : 0.5-1.0 adjustable
HC level at idle speed - ppm 300
CO2 level at idle speed - vol %CO2 13-16
o2 level at idle speed - vol % o2 0.5 - 2.0

no cat so no other readings

Hope this helps
Steve