Just had the MOT data back on my MY99 & it's failed on natural idle test . CO level was 4.15% at 783rpm - max CO allowed 0.5%.

Passed fast idle test OK.

The idle speed has been a bit lumpy of late, though this was supposed to have been sorted at the 3 year service yesterday. Air flow meter was also removed & cleaned.

Any ideas as to what might be causing this?? Car is MY99 with ITG filter, Scooby Sport SS & BB.

Hugh

Have spoken to Quenbys & they've suggested exhaust CO2 sensor or airflow sensor.

 

Lambda (O2) sensor would be favourite.

 

Do you only have the cat on the d/p?

Tony

 

Tony - Correct: no cat in SS.

John - Thanks

H

 

That sounds about normal then, you can fail cold idle, its hot idle that they wont let you fail as most cars still push more fuel mixture when cold, wouldnt worry about it, my old r1916v always failed cold

Tony

 

Tony,

I wish that were the case.

Fail on cold idle = failed MOT altogether even if the car passes on everything else

Even though I work for the group that owns the MOT centre no favours. VI are trying to be very tough & will retract your licence if you're found to be 'assisting' vehicles to pass.

H

 

Idle mixture is dependant on a good lamda sensor (O2 sensor), I'd suspect that.

 

Interesting to know Huge.

Although I wasn't going to get my car done at Quenby's I have a MY99 and am putting an ITG filter and Scoobysport BB on. Was going to get it MOT'ed (first one) and then replace the DP cat with a Scoobysport. Everyone says it will still pass but now I'm not so sure.

J

 

mine failed like that... new lambda... ecu reset... and hard blast to mot station... Where I get mine done theres a dual carrige way and a couple of roundabouts... all the lads and owners... stood and watched me warm up the tyres.. (I mean engine..) passed fine then..

David