Technical Lambda Value - 1st MOT

[s130]

Well my 500X had it's 1st MOT the other day.

No issues but I made this Lambda observation:

OVERALL RESULT EXHAUST EMISSIONS TEST PASS

RESULT Diagnosis Limits
====== Min Max

Fast Idle Test Pass
--------------
Engine Speed = Manual Check RPM Pass 2500 3000
CO level = 0.00 %vol Pass - 0.20
HC level = 3 ppm Pass - 200
Lambda = 1.029 Pass 0.970 1.030

1.029 is just below the limit of 1.030

Don't think I'm worried about it and can possibly explain it by a not so hot engine as it could have been.

 

[Alanw47]

Well my 500X had it's 1st MOT the other day.



No issues but I made this Lambda observation:



OVERALL RESULT EXHAUST EMISSIONS TEST PASS



RESULT Diagnosis Limits

====== Min Max



Fast Idle Test Pass

--------------

Engine Speed = Manual Check RPM Pass 2500 3000

CO level = 0.00 %vol Pass - 0.20

HC level = 3 ppm Pass - 200

Lambda = 1.029 Pass 0.970 1.030



1.029 is just below the limit of 1.030



Don't think I'm worried about it and can possibly explain it by a not so hot engine as it could have been.

No guarantees that this is correct but I found this on Honest John

"OK, let's see if I've got this right.

A value higher than 1.00 basically means that in combustion, the ratio of air to fuel used is above what it is supposed to be, and a value lower than 1.00 basically means that the air to fuel ratio is below what it is supposed to be.

Hence a values of less that 1.00 indicate poorer fuel efficiency, while values of over 1.00 indicate better fuel efficiency - but are associated with higher temperatures, which could cause damage to the engine. "

 

[TrevC]

Possibly worth a couple of tankfuls of superfuel (eg V-Power) before the test? I use it all the time as it's supposed to keep the engine clean. No idea how much good it does, but with my annual mileage the extra cost isn't too bad.
I'll try to remember to post my results when mine is MoT'd in September. From memory s130 yours is a 1.4 MA like mine?

 

[Alanw47]

Possibly worth a couple of tankfuls of superfuel (eg V-Power) before the test? I use it all the time as it's supposed to keep the engine clean. No idea how much good it does, but with my annual mileage the extra cost isn't too bad.
I'll try to remember to post my results when mine is MoT'd in September. From memory s130 yours is a 1.4 MA like mine?

I use V-Power all the time in my 2.0MJ and I get about 2 mpg more than standard diesel, but I mainly use it for a clean engine and emissions. I do about 10k miles per year but am quite happy to pay the extra.

 

[TrevC]

Yes, a few diesel owners I know have reported a slight improvement in mpg running V-Power. I've not noticed it with the petrol (I've never owned a diesel) but my 500 hatch with the twinair engine seemed to run a bit smoother with the expensive stuff. Could have been in my head though!

 

[Alanw47]

Yes, a few diesel owners I know have reported a slight improvement in mpg running V-Power. I've not noticed it with the petrol (I've never owned a diesel) but my 500 hatch with the twinair engine seemed to run a bit smoother with the expensive stuff. Could have been in my head though!

My personal, uninformed, opinion is that these modern, small, high output engines would probably benefit from the expensive stuff even if they don't actually need it