MOT pass but emissions up 1 year later - perleman
Hi,
I have a Golf GTI 1.8T 150BHP. I just had it MOTed and noticed that the CO and HC are approximately double what they were last year. Since last year I had it Superchipped - could this account for the change, or is it a sign of the engine or cat being worn? Here are the results with milage & age:

MOT 1 - 3.5 years old & 40k miles: HC = 33, Lambda = 1 (can't remember CO I'm afraid)
MOT 2 - (Superchipped) - 4.5 years old & 54k miles: HC = 60, Lambda = 1

MOT pass but emissions up 1 year later - martint123
I'd have thought the chip would make it run richer - if you expect to get more power them something must be given up in exchange - and most often it is emissions. Can you pop back and ask them to do a quick test with the original chip in?. Do you get a warranty from the chip supplier that it will pas an MOT emissions test?

Martin
MOT pass but emissions up 1 year later - Armitage Shanks {p}
Did it fail the MOT? Do your insurers know about the chip?
MOT pass but emissions up 1 year later - Dynamic Dave
Did it fail the MOT?


Subject header says it passed.
MOT pass but emissions up 1 year later - Armitage Shanks {p}
So it did - sorry!
MOT pass but emissions up 1 year later - Falkirk Bairn
Italian tune up required?
Redex for 2/3 fills?

Just a couple of suggestions.
MOT pass but emissions up 1 year later - perleman
Hi,
It did pass fine - I was just wondering whether to be worried that the emmisions seems to have gone up a fair bit, and whether this was an early indication of an engine problem.

Sadly it is quite a palava to get it returned to stock so my curiosity will have to go unanswered - in any means, I guess I'll have my answer next year if it's got any worse!

What's an Italian tune-up?
MOT pass but emissions up 1 year later - Falkirk Bairn
Bombing it along the road in a lower gear than normal (after suitably warming the car up prior to this)
and the crap comes out of the exhaust. Redex + italian tune-up is even better.
MOT pass but emissions up 1 year later - Armitage Shanks {p}
Roughly speaking, drive the car on the open road, out of urban speed limits, one or 2 gears lower than would be normal for the speed. Ie, at the red line and 50 or 60 mph for a some miles/minutes. This will blow loads of crud out of the engine and exhausr system and, if combined with some Redex or Miller's Diesel for a diesel, will do your recorded emission sa power of good. A 'Forum Search' may reveal more thoughts (in the box top right labelled BackRoom)
MOT pass but emissions up 1 year later - Hamsafar
Both readings show a Lambda of exactly 1, but the reading is usually given to at least two decimel places. If they really were both exactly 1, then the HC reading shows that there is unburned fuel in the exhaust stream, yet the Lambda value shows that the mixture is perfect, so I would suggest a false Lambda value (o2 sensor) or inefficient catalytic convertor.
MOT pass but emissions up 1 year later - Altea Ego
"I was just wondering whether to be worried that the emmisions seems to have gone up a fair bit, and whether this was an early indication of an engine problem."


Ok to make it perfectly clear, Its because you have had it chipped.
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TourVanMan TM < Ex RF >
MOT pass but emissions up 1 year later - John S
Pass value for HC is 200, so a figure of 60 isn't a problem. My BMW regularly shows HC of 50 ish, and varies year to year. Lambda was 1.001 last time. It may be the chip, but i wouldn't worry about it

JS.
MOT pass but emissions up 1 year later - Cliff Pope
I've seen them vary by much more than that just over a period of a few minutes running. Mots I've watched, the tester does a few runs and then picks the first one to pass on all scores. If you picked two random HC values they'd be all over the place and the apparent trend would tell you nothing. Just be glad it passed.
MOT pass but emissions up 1 year later - perleman
Thanks to all for your replies on this, I think I've read enough to keep the paranoia at bay for another 11 months.