22 replies to this topic

[Don't Panic]

Hey guys, I've got to get my emissions sorted for the MOT on Thursday.

I've set the mixture at idle, and i bought a colortune just to check so its a nice lightish blue at idle, when I increase the revs its stays blue for a while then goes orange. I can't see my tach and the colortune at the same time but it sounds like about 2500 - 3500RPM when it goes orange, i'm worried that this will cause it too fail on emissions. What can i do?

I'll take it to a rolling road for a setup after the MOT.

[superted87]

am i being silly?? why not take it on the RR before or is time of the essence??

ted

[fikus01]

cud just pre-warn the mot guy that the carb may need adjustment!! not sure if ur stil allowed but su carbs used to get an adjustment allowance because of jet/needle wear!!

colourtune aint all that great at setting emmissions i found lrp, leaded and unleaded all gave different results!!!! gunsens do a emmissions meter tho!! look in halfords!

[minislapper]

The emissions are only checked at idle anyway so the mixture at 2500 rpm and no load will only affect the drivability of the car and not the MOT !!

And I've always managed to set the idle mixture successfully with a Colortune so you should be ok !

[charlie]

I use colortune and sailed through the emission test.

[miniboo]

SNAP

[Jammy]

Go and get one of the decent petrols (Shell Optimax, Bp Ultimate, Esso Energy) and drive for about 30 minutes if your worried about emissions that much.

[TimS]

Emissions are also checked at fast idle as well as idle

[Don't Panic]

Lots of replys, thanks guys.

But Flappypasticbits is right they check at idle and fast idle (2500 - 3000RPM)

Already runs on BP Ultimate Jammy and the emissions were still too high.

I would take it to the RR first but it doesn't have an MOT and i'd really like it back on the road by the end of the week. Plus im in aberdeen so the RR is about 100miles away www.thetuningshop.co.uk.

I guess I'll just take it in for the MOT and if it fails worry about it then... i've looked it up and if it only fails on emissions you get a free retest if you bring it back by the end of the following day.

is it possible to adjust the mixture at fast idle? or is this entirely todo with the needle profile?

[Jammy]

Try notching up to a different spark plug. If you have NGK BP6ES (or BPR6ES for electronic ignition), then go to BP®7ES, they burn hotter so burn more C**p off resulting in a cleaner burn, the downside is that the spark plug doesn't last as long.

These are only temporary measures of course to get through the MOT. You should run the correct spark plugs for your engine (it maybe that 7s are more suited to your engine afterall - my 1425 had to run 7s at least, preferably 8s). You should look at whether your mixture is correct and whether that is the cause of your high emissions.

Sorry, just re-read the problem, I wouldn't worry about the rich spot too much, I don't think emissions are tested that high up the rev-range, even fast idle is about 1500rpm I believe.

[Don't Panic]

Thanks for that Jammy, Intresting to know about the spark plugs... of course looking at it through the colortune means you only see how it performs with the colortune spark.

[Grayedout]

Never had mine checked at fast idle !!!!!

Thought they only did that when the Hydrocarbons fail at idle !!!

[Don't Panic]

Hey guys, BIG THANKS!!! It passed...

had to run it rather lean to get through the emissions, but used the colortune again when i got home. RR session will be booked in soon!

[mini93]

well done with passing it, is it still drivable being tuned by colourtune? iv seen it but never thort about getting one...i want timing light 1st

[Don't Panic]

Yeah been driving all afternoon!

Its quite a useful tool... tho my timing is ok so i didn't need to worry about that. To be honest I got the colortune to check that i had the right mixture and i'd set it pretty well just by listening to the engine. It did show me that when i rev the engine i have a rich spot.