NCT emission failure

[rb25First]

Hi Guys, wondering if anyone can help me out. Car went in to the NCT (1996 r33 gtst). Passed on everything except high rev emissions. HC's are fine. Lambda is 0.95 shud be between 0.97 and 1.03... CO2 was 1.73 should be under .3... And ideas... Spec as far as I am aware are HKS turbo, splitfire coils, .8 gapped plugs (not sure of the number, they were recommended, was .6mm plugs...) Hks fconis ecu, (but I have removed this for today as it failed before... Badly..) so standard ecu for today... New lambda... Standard cat... Hks boost controller...

Just wondering if anyone has any ideas on what to do next.. I tried using diptene as well...

Any help greatly appreciated

Cheers

[Ptank]

Iv heard and know of people using an evo 8 cat. All cars are well spec'd and wouldnt have a hope in passing with a standard cat.

[rb25First]

I've read somewhere as well that the water temp sensor can cause issues....

[20vees]

Diptane needs to be used up to a week before the test of not 3days .
Yes change your ecu water temp sensor and your water thermostat incase seone drilled it out or you have a low temp one .
if your cat and engine never reach the normal operating temp the emissions will be all over the place also drive tge car for at least an hour before the test .give her socks for the last ten minutes before the test

[rb25First]

Finally got it passed.... Alot of small jobs done since... not sure what fixed it....

Washed CAT out with Bilberry wheel cleaner.. Amazing the stuff that came out of it....
Re-fitted .8mm spark plugs...
New air filter....
Found slight pin hole in fuel line near the rail... (I suspect this is the main culprit, but not sure...)
Cleaned coilpacks
Full Service.....

It went from being 1.95 on high Co2 to running a 0.01.... Sign of a healthly engine I was told... Compression test showed near 150 on all cylinders aswell... 149-151....

Over a years test on her now... debating whether to sell it now... but so hard to let go