MOT happiness/emissions question

NCCMUR · Post by **NCCMUR** » Fri Mar 08, 2013 8:34 pm

hi lads,

passed her MOT today

advisories for a n/s droplink and n/s track rod end and rear disks (no real concern)

the concern was in relation to the emissions, on the initial test the CO was too high and then the HC were too high,apparantly he dumped in some additive or other to bring the readings down.

the question is whats causing the emissions to be so high,and what needs to be fixed.

1. knackered o2 sensor? (no CEL light coming on on dashboard to indicate fault)
2. knackered cat ?

any ideas fellas?

Post by **Pushki** » Fri Mar 08, 2013 8:41 pm

1. Knackered O2 sensor.

The oxygen sensor in most Honda's has a design life of approx. 8 years.
Although your O2 sensor may not have failed completely, they start to become less efficient with age.
They become "lazy" and do not respond as quickly as when new, this causes rough running and poor fuel economy.
They can also shorten the life of your catalytic converter, which is another expensive item to replace.
So if your Prelude hasn't had a replacement oxygen sensor yet, get one.
Although you can find "generic" sensors much cheaper that do the job, they do not necessarily work as efficiently as the OEM one.

NCCMUR · Post by **NCCMUR** » Fri Mar 08, 2013 8:47 pm

from where can i purchase said item?

Post by **Merlin** » Fri Mar 08, 2013 8:58 pm

http://www.ngkpartfinder.co.uk

What were your emissions results?

NCCMUR · Post by **NCCMUR** » Fri Mar 08, 2013 9:08 pm

@merlin

So would these results definately confirm a duff o2 sensor?

Post by **Merlin** » Fri Mar 08, 2013 9:28 pm

Yup the first Lambda test was a failure so that is probably a good place to start.

My 5th had an MOT just the other day and it was (slightly different engine):

CO: 0.17% (pass is <0.20%)
HC: 22ppm (pass is <200)
Lambda: 0.996 (pass is 0.97 - 1.03)

NCCMUR · Post by **NCCMUR** » Fri Mar 08, 2013 9:32 pm

i just missed the one you had for sale too

I looked at the ngk partfinder page but i cant see a price

Post by **Pushki** » Fri Mar 08, 2013 9:34 pm

NCCMUR wrote:I looked at the ngk partfinder page but i cant see a price

They're approx £60 new, give or take.

I got mine from RockAuto in the US.

Post by **Merlin** » Fri Mar 08, 2013 9:34 pm

The first link I posted above was £56 on Amazon

The 97-98 only one.

NCCMUR · Post by **NCCMUR** » Fri Mar 08, 2013 9:36 pm

Ok cheers guys its on my to do list