Exhaust leak? Failed emissions

[Gooose]

Can anyone shed any light on my resent not failure

Here’s my results

CO limit < 0.20% result 0.00
HC limit < 200pm result 1ppm
Lamba value limit 0.96 - 1.03 result 1.047

My car is a Suzuki Grand Vitara 07 plate petrol, I resently changed the whole exhaust, and changed one of the lamba sensors and the other one was previously changed a while back.

Could the result be a leak on the exhaust? There’s no warning light on the dash, the car drives well, and there’s no noise either.

I’m not a mechanic so whilst I can do bits and bobs I’m not the best at diagnosing problems!

[paintman]

Yes it could.
Did you use plenty of exhaust sealant paste on the post cat joints?

[Gooose]

paintman said:

Yes it could.
Did you use plenty of exhaust sealant paste on the post cat joints?

I didn’t put any on, I heard conflicting advice about using it tbh.

My thinking is that the other readings are ok so the cat is working, there’s no warning lights so the cat by the lamba sensors are ok, and the sensors are ok as well. I can’t hear any noise which would suggest the leak if any is down the end of the exhaust rather than close to the engine?

I did see a video of someone putting a vacuum cleaner hose on the Hoover exhaust side and putting this on the exhaust pipe, then spraying the joints with fairy liquid water mix to see for leaks when pressurised. Would this work in practice?

[paintman]

Gooose said:

paintman said:

Yes it could.
Did you use plenty of exhaust sealant paste on the post cat joints?

I didn’t put any on, I heard conflicting advice about using it tbh.

My thinking is that the other readings are ok so the cat is working, there’s no warning lights so the cat by the lamba sensors are ok, and the sensors are ok as well. I can’t hear any noise which would suggest the leak if any is down the end of the exhaust rather than close to the engine?

I did see a video of someone putting a vacuum cleaner hose on the Hoover exhaust side and putting this on the exhaust pipe, then spraying the joints with fairy liquid water mix to see for leaks when pressurised. Would this work in practice

Take it apart & reassemble using sealant paste.
Only needs a small leak.
No idea about the Hoover thing.

[catfishdb]

Might never have thought of the vacuum idea.

To narrow down the area of leakage......while the engine is running, put your hand over the end of the exhaust tip. Effectively trying to force the exhaust gas out of the leakage areas. The hand over the tip can increase the sound at the area that leaks. Hopefully making the leak easier to locate.

Back to the snack table I go.

Arthur

[Gooose]

Did the hoover tip and it worked a treat saw it bubbling on the centre box joint, split it and smashed a load of exhaust paste in there, fingers crossed it will be ok!