MOT/Emissions failure

[IcewraithUK 0]

Hi guys'n'gals

Hoping for a flash of inspiration here - my VR6 has just failed it's MOT due to a massive emissions spike at the 2500-3000rpm mark...

It's a '96 Supercharged (NS Racing/Raj did the work) that has been running fine to date. At idle, the lambda and emissions all seems okay. Move the rpm up to 2500+ and the CO goes from under .2 to about 10! Insta fail basically. Lamba values change, so that would seem to be working okay.

Now I noticed a small oil leak out of the s/c that was dripping down onto the air filter (terrible placement for the thing, directly under the s/c) so I've tightened up the banjos on that and stopped the leak (I think) but I can't see how even a restricted air flow could cause the car to over fuel so badly...

Any idea?

Cheers,

Craig

[petervr6 0]

try changing the lamba probe same happened to mine and its ok now.

[mightyvr6 0]

What chip are you running? The giac chips which are supplyed with the kit are well known for massive overfueling.

Or the maf could be on its way out causing it to run too rich.

[IcewraithUK 0]

Hi,

We put a new lambda in when we put the s/c in, so fairly sure its not that

Yup, it's a GIAC Damn - I've got my old Dastek Unichip, would they be able to program that to run the s/c?

Cheers for the help

Craig

[mightyvr6 0]

Have you got a spare maf to swap or you could swap back to the standard chip and see if that works. If you know someone with vag-com they could tell you the lambda readings with the engine running then you could swap parts to try and work out why its overfueling.