emissions

[greenracing]

Had the cerb mot'd on the 27th, good news, straight through, not even one advisory. However, the emissions on both sides were fairly different and I am thinking that the cam timing may not be spot on or the throttle bodies not fully balanced? Results below, anyone have any suggestions?

N/S
CO % vol 0.203
HC ppm vol 6
Lambda 1.028

OS
CO % vol 0.022
HC ppm vol 58
Lambda 1.055

I guess that the NS is actually running better because there is less unburnt fuel? I will be checking both the cam and the throttle balance but wondered if there was anything else to look for whilst I am there? Sparks and HTs are all new. Its a 4.5 RR

[aide]

I can have a look at my last mot this eve and post the readings they measured for comparison if that helps?

[greenracing]

Would be good to see some other readings just to see how close the numbers are on your banks. Planning to have a look at mine on the weekend then get the garage to run the test again if I find anything that's out of sync.

[gruffalo]

Don't forgat the engine runs as 2 four cylinder units sharing one crank, 2 throttle pots, one for each bank, 8 throttle bodies that can be set individually and so on, 8 bores that could wear at a different rate.

In summary could be almost anything. It would worth starting with the engine set up pocress as detailed in the workshop manual.

[aide]

Funnliy enough the last mot I have only has one set of emissions values.
CO % vol 0.177
HC ppm vol 66
Lambda 1.004

[gruffalo]

aide said:

Funnliy enough the last mot I have only has one set of emissions values.
CO % vol 0.177
HC ppm vol 66
Lambda 1.004

Normal for an MOT that if one side passes that is all that is checked, never have both banks on mine been tested at MOT time.

[greenracing]

If the pipes aren't linked then they should check both sides as they are seperate banks running seperate emmisions. If you have linked pipes then the just check one side. All my old mots have both sides. Anyway, only another day till I get to the checking!

An earlier post mentioned each throttle bodie could be setup, what can be altered/setup?

[Vee8ight]

Before I bought mine, it had a CO of 1.5% at the mot and it has cats fitted! Something tells me they might not be working!

[greenracing]

What was the hc?

[gruffalo]

greenracing said:

If the pipes aren't linked then they should check both sides as they are seperate banks running seperate emmisions. If you have linked pipes then the just check one side. All my old mots have both sides. Anyway, only another day till I get to the checking!

An earlier post mentioned each throttle bodie could be setup, what can be altered/setup?

Interesting as I have only ever seen the readout from one side and when watching the test they have only tested one side, always the closest to where they are standing at the time so just lazy then I guess:0)

[scyman]

Hi,
Here are the readings from my '98 4.2. Valve clearances were set within the last few hundred miles and I'd just fitted two new cats for the MOT.

N/S
CO 0.16%
HC 12ppm
Lambda 1.00

O/S
CO 0.13%
HC 11ppm
Lambda 1.03

Hope this helps!