Hi
New on here,managed to find all the help I needed during the build through searching on here,but now I'm struggling!
Went for my sva yesterday and failed on high co2 emissions.I'm running a nissan 2litre turbo from my old sx,all engine components are standard including the ecu. The co2 was fluctuating from around 0.7,slowely down to about 0.4 before suddenly jumping back up again? The lambda is new and that read fine.
Just baffles me cause there's no adjustment anywhere and seems strange fluctuating.
Any guru's out there who might be able to point me in the right direction?

Chris

I don't think i could have got it much hotter to be honest,it looked as if whatever controls it all was trying to lean the mixture out then giving up!

How far have you driven since reconnecting the battery? It took my Ford ECU at least 50 miles to relearn it's settings and sort itself out.

Haven't actually been able to drive it anywhere,but I've had it running for a good while,it was lumpy the first time for about 20 minutes but seems to run fine now.Do you think maybe I need to drive it as the engine's not been under load?

when i had my 200sx it was decatted all year round apart from MOT time. it was running just shy of 300bhp on the standard ECU. fitting the standard cat back into the system worked perfect every time... the emissions always sailed through easily, so i can only think your cat isnt upto the job, or not hot enough?

As long as your lambda is working your standard ecu should be able to sort out the rest.

does it have standard injectors fitted?

yeah,its all standard apart from the cat which I was assured would be up to the job!If its not its going back!Was hoping it could be narrowed down to a sensor or something tho!

Is the ECU actually going into closed loop? Monitor the lambda voltage and see if it's switching up and and down once the engine has fully warmed.

Is it the origional air box?

Sorted my blade out by only partially blocking off one of the carb tubes that origionally went to the airbox, having been told to completely block it.

My probs were like yours - fluctuating CO and PPM, with steady lambda.