LS3 Emissions Fail - IVA

[RussHowell]

Congrats on the pass, on what must be one of the quickest builds! Look forward to seeing next vid.
Will you be selling for another build, or is this one a keeper?

Hi Kevin,

I was asked to build this Cobra as it is quite difficult to find a more retro looking model for sale.
I have another request starting in a couple of weeks......series two of the build videos 

Cheers
Russ

[Mike Hamblin]

Russ
Congrats on getting a pass.

On to registration and trimming.

Then start your next build.

[KevinW]

 
Congrats on the pass, on what must be one of the quickest builds! Look forward to seeing next vid.
Will you be selling for another build, or is this one a keeper?

[RussHowell]

Just to close this off, i have now passed IVA emissions test.

I reassembled exhausts and doubled down on tightening and ensuring no gaps\air leaks and am pretty sure that was the fix.
I did also have Canems remote-in to the ecu and make a couple of minor changes but dont think it would have made the huge difference that i saw in the results.

Cheers
Russ

[Mike Hamblin]

Hi Russ
Just re check your exhaust J pipe to manifold gasket, they do tend to leak a bit, the as supplied LS3 manifold has a recess for a crush ring gasket, and if you fit flat gasket it tends to leak.  Some remove the manifold's and have them skimmed flat, which makes sense. then a flat gasket will seal correctly. If you are using a crush gasket make sure its square and not leaking.

Or try any of these.
Here are a couple of suggestions
 
Are you running on the new Canems ECU map or the old one.
As I know Dave offered to load a new one on mine, suppose to be improved.
Maybe ask Dave to re check all the settings on your ECU remotely, then try again at an MOT place

 
These are the most common causes
 
Carbon Monoxide (CO) – this is an indication of the air-to-fuel ratio; too much fuel in the exhaust gases results in a high CO reading. This can be caused by a faulty catalytic converter. Hydrocarbons (HC) – indicates unburned fuel exiting the exhaust; the more incomplete the combustion, the higher the HC reading.
 
Generally speaking, on fuel injected vehicles, high CO means too much fuel is being delivered to the engine for the amount of air entering the intake manifold. This is the petrol that has combusted, but not completely. This gas is formed in the cylinders when there is incomplete combustion and an excess of fuel.
 
What causes high CO emissions?
What causes carbon monoxide poisoning from vehicles? Operating a vehicle with a defective exhaust system. Operating a vehicle with a defective emission system or poorly tuned engine.
 
 
This might help you
Running rich
Defective O2 sensor
Leaky fuel injector
Clogged air filter
Timing issues
Bad Maff sensor

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[RussHowell]

So I breezed through IVA right up until emissions.
The tester allowed plenty of time for the engine\cats to be hot and probed both exhausts but still failed on:
CO and Lambda.  HC was fine.

It did smell a bit rich.

I had Dave at Canems connect in and amend some settings, and  i refitted everything to ensure no air leaks, but then still failed at local MOT centre.

CO still around 1.4 and needs to be 0.30 max
Lambda 0.95 and needs to be 0.97 min

Quite surprised new modern engine has an issue, so hoping someone might know what to look at please.

Maybe fill up on E5 fuel as it burns cleaner although not sure my braided rubber fuel lines will like it?

Thanks
Russ