MOT tomorrow - will it fail with gtt manifold

[s33gav]

Since I've had the GTT manifold on the exhaust emissions light is almost constantly on. I'm just wondering whether this will be enough to fail the MOT tomorrow?

Has anyone else in the same situation had their MOT yet?

Cheers
Gav

[Bhozar]

If the light is on it will fail AFAIK.

I have the GTT manifold and the light wasnt on when I had the GTT sports cat fitted and it passed with no problems.

[Loui]

Quote: Originally Posted by s33gav (original)

Since I've had the GTT manifold on the exhaust emissions light is almost constantly on. I'm just wondering whether this will be enough to fail the MOT tomorrow?

Has anyone else in the same situation had their MOT yet?

Cheers
Gav

If you have got a sports cat really the light shoudlnt be on. Really we could do with some more info to answer the question or hopefully try an correct the issue.

How old is the car?
Is it a JCW or has it got the JCW airbox with the opening flap?
Have you checked the cat has it burnt out?
Is your bypass valve working?
Has the car lost any performance?

Just a few things that might help us to throw some light on the issue for you

[s33gav]

The car is 4 years old, proper JCW with extra bits from GTT (manifold, crank pulley, modified bypass valve). It was only fitted a few months ago and since then the light has come on. If drive it slowly for a while the light goes off.

Roland told me it was nothing to worry about and the emissions light is only a flag, and doesn't necessarily mean it's a fault. It's never worried me until now, and just thought I'd check with you guys.

Performance is fine, car drives like new.

[Capsaisin]

In a way Roland is correct. The light being on is an indication that something is amiss, which the ECU does not like. But that could be just a dodgy cat sensor or just a leak at a joint, for example.
However, as far as the MOT goes, it will depend on the readings they get from the emissions test.

You might actually be wiser after you have seen the emissions results, and as your MOT is tomorrow I guess there is not much you can do about it except worry.

For comparison my MCS with standard manifold/cat gave:

Fast Idle: 0.008 %vol CO, 0 ppm vol HC at 0.999 Lambda
Natural Idle: 0.001 %vol CO

[Ant FR]

to be honest i would look at getting it back to Roland as the light should not be on, my milltek one has never come on and i too have an MOT next week.

Also has the car ever been mapped since you did the GTT mods

[s33gav]

Interesting. I was led to believe it wasn't an issue with the light being on and told that it can come on with a normal JCW, and also after doing some searching it seemed other people with sports cat/manifold had seen this light come on.

It was never mapped since the mods, Roland took it out and said eh felt it was fine, no pinking etc and pulled as expected.

Other than the light being on everything is great. I am thinking of selling the manifold as it happens, as I need the funds to pay for my 205, but I'm now wondering whether I should do it before or after the MOT.

If it fails tomorrow I'm stuck, as I'll need to go home, replace it, then go back to retest (if they can do it then) and time costs money in my profession, which is why I'm thinking of replacing it tonight just to be safe.

It would be good to know if it fails though with the manifold and light on.

[Lucky Dave]

The emmisions light is driven by the second o2 sensor and has no control over what the ecu will think or do. Its just there to monitor emisions.

When under load the cars air to fuel mix will hopefully become richer, a sports cat works in a way to reduce restriction in the airflow, by letting more gasses past.

Under heavy high fuel wide open throttle the second 02 sensor may see a little to much richness for 1/10th of a second and flag the emissions light.

A standard car would only light the emission light under fault conditions, a modified car can light it under heavy right foot use, TBH its better to have a little more fuel under load to save you topping your engine.

It also would suggest you do have the JCW map running in your car as they do run rich at high revs to protect the engine.

Like you say a few steady drives will turn the light off as the ecu needs to see a number a good samples before it can turn the light off on its own.

I hope that helps.

[Ant FR]

Why not do an ECU reset ( proper one) before it goes in

[s33gav]

Cheers for the replies people. I'll decide later whether to replace the manifold before the mot, but will report back either way of the results.

Fingers crossed.
Cheers.

EDIT: Will an ECU reset remove the light then? I'll do a search for this, I seem to remember reading about this - remembered there was a basic one with pressing the button on the dash or something. I'm not sure what affect this will have on the car though.

[ScottyBoy]

I personnally drive with this light on constantly and what lucky dave has mentioned is correct, if i drive slowly or less right foot it doesnt come on, if i get close to WOT it pops on, i wouldnt worry and i guess it will be fine.... there is many members that ive spoke to which have this light on not sure if they have MOT'd it though.

Scott

[AndyH_MCS]

Also make sure you warm the car up before taking it to the testing station. If you don't it will probably fail on emmisions as well.

Drive it sensibly for a while if that makes the light go out then pop it in for the MOT

[Ant FR]

or just do as i am, get a mate to MOT it..............

[Loui]

Quote: Originally Posted by s33gav (original)

The car is 4 years old, proper JCW with extra bits from GTT (manifold, crank pulley, modified bypass valve). It was only fitted a few months ago and since then the light has come on. If drive it slowly for a while the light goes off.

Roland told me it was nothing to worry about and the emissions light is only a flag, and doesn't necessarily mean it's a fault. It's never worried me until now, and just thought I'd check with you guys.

Performance is fine, car drives like new.

So its a 200 JCW car? Has it got the airbox on? reason i ask is i had the light coming on intermitently for about 7 months an it was a really soft problem due to the airbox, an raised boost pressure, we tried sensors to cure it, checked the cat, changed the top wiring harness amongst other things an the problem kept reocurring an would go away for a while when the light was reset then a few hundred miles return. The cure cost 5p

[s33gav]

Quote: Originally Posted by Loui (original)

So its a 200 JCW car? Has it got the airbox on? reason i ask is i had the light coming on intermitently for about 7 months an it was a really soft problem due to the airbox, an raised boost pressure, we tried sensors to cure it, checked the cat, changed the top wiring harness amongst other things an the problem kept reocurring an would go away for a while when the light was reset then a few hundred miles return. The cure cost 5p

It's a 210 with the airbox but it has the gtt cold ram filter inside.

What was your cure then?