Help - MOT fail on HC emissions - now fixed!

I 'nipped' to Berts last year for my service and MOT. 
LeeO is right, so long as you're booked in that's the requirement from the law. It doesn't dictate how far. 

yep lean co mixture will cause the HC to rise, 0.3 is way low for a kjet i would want it at at about 1-1.5%. general consensus on 16v is 1.8% for a happy car and its basically the same setup

check everything else is ok first though, could be an air leak or some other issue causing both

on my digifant co was around 0.1-2% and HC were thru the roof! as soon as co corrected HC dropped right back

rubjonny  

John I'm jumping in on Richards post but as you may remember. 
I have a Digifant on mine, so what sort of CO emission should I be seeing to know all is well please? 

Sorry to hear about this Rich! 

Sent from my Mobile Phone. 

book spec is 1% +/- 0.5%, id rather see it 1-1.5% than less though

rubjonny said

book spec is 1% +/- 0.5%, id rather see it 1-1.5% than less though

Thanks John! 

Sent from my Mobile Phone. 

Can't find any air leaks, old plug leads back on and I will ask garage to set CO2 at 1.5% and keep fingers crossed.

Thank you everyone for your advice.

RichardHall said

Can't find any air leaks, old plug leads back on and I will ask garage to set CO2 at 1.5% and keep fingers crossed.

Thank you everyone for your advice.

The 'old boy' at the garage opposite mine always tells me K-Jets on this age of GTI should be set for CO ideally 0.8-1.2 - I think the Autodata books say that too.

book spec for a kjet is 0.5-1.5%, go with what the old boy says though they always know best

First chance to take car back for retest today and have the front ball joint replaced.  Was a bit concerned when I arrived and asked them to set the C02 at 1.5 instead of 0.30 when they said their machine was only for sampling for MOT not for tuning, but they said they would try.

Anyway, need not have worried, when they tested it, C02 remained at 0.31 but HC just 13 instead of 1500.  Replacing the ignition leads with the old ones must have done the trick, a lesson there -if it's been good enough for 32yrs dont fiddle!  Anyway I supposed I ought to find somewhere to set the C02 a bit higher, but it does seem to run fine.

Back from MOT centre, on-line to tax it and then took out for a good run, smiling every mile.

Nice one rich 👍

Smokin!   

That's great news - but worrying that a new set of leads would cause such problems. Would you be willing to share the brand or supplier, just in case they are one to avoid in future?
Lee

I bought them from ECP, they are branded ProSpark, double silicone.  Only reason I got them was at they looked like the originals which the polished caps were looking tarnished. I've sinced polished them up and they look just as good.

That's interesting - the one time ECP really let me down was over the supply of a set of HT leads (same brand as you). They seemed incapable of supplying a set suitable for my 86 Cabby. In the end I bought a set of Blue Igniters from C&R - they use OEM caps at each end of the lead. I can't find them on the C&R site now, but I think they have an ebay shop.
Lee

oem bosch or beru make is all you need, i get mine from
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