MOT - emissions test

System

Is it really true that a 15-year old car can achieve zero emissions at all, even after a good service, tune-up and petrol cleaner?

If it had improved from a marginal fail to a marginal pass the story would have seemed entirely plausible. It just seems a little bit too perfect.


Just as a matter of interest, what reading does the machine give if the probe is just held in the air? Would that be zero carbon monoxide by any chance?

mcjordi

red_eye wrote: »

with out the HT probe how would the analyser know what rpm the engine is doing? the tester could be idling the engine when the analyser is measuring fast idle emission.

i think my tester just guess's but then again its never failed on emissions yet.

swiftnick

Clifford_Pope wrote: »

Is it really true that a 15-year old car can achieve zero emissions at all, even after a good service, tune-up and petrol cleaner?

If it had improved from a marginal fail to a marginal pass the story would have seemed entirely plausible. It just seems a little bit too perfect.


Just as a matter of interest, what reading does the machine give if the probe is just held in the air? Would that be zero carbon monoxide by any chance?

Nope it would fail the lambda test.

Mankysteve

red_eye wrote: »

leads are not long enough. you have a probe in the tail pipe, another on one of the HT lead and one in the dip stick

Connecting anything to that leads on my petrol car would be quite challenging, due to there not being any to connect too.

red_eye

Clifford_Pope wrote: »

Is it really true that a 15-year old car can achieve zero emissions at all, even after a good service, tune-up and petrol cleaner?

If it had improved from a marginal fail to a marginal pass the story would have seemed entirely plausible. It just seems a little bit too perfect.


Just as a matter of interest, what reading does the machine give if the probe is just held in the air? Would that be zero carbon monoxide by any chance?

yes it is true any car can have zero emissions as long as you dont start the engine.

holding a probe in the air will not show any reading it will just flash insert probe as it is detecting excessive o2

red_eye

mcjordi wrote: »

i think my tester just guess's but then again its never failed on emissions yet.

not using vosa approved equipment then. An approved analyser wont start the test without the HT probe.

red_eye

Mankysteve wrote: »

Connecting anything to that leads on my petrol car would be quite challenging, due to there not being any to connect too.

sure it does, there would be leads going to the spark plugs

ILW

swiftnick wrote: »

Nope it would fail the lambda test.

Would a 15 year old car necessarily have a lambda sensor? Might be carb.

Paperbird

red_eye wrote: »

sure it does, there would be leads going to the spark plugs

There's lots of petrol engined cars available these days with no leads going to the plugs. They have coil packs that connect direct to the plugs.