NCT Emissions failure help needed

Pique

Hi all,

Got a problem with my cars emissions.
Here's the story:
Its a 01 Forester witha de-cat ss exhaust.
I failed the NCT on emissions of
Low idle:
CO 1.03
HC 176ppm
High Idle:
Lambda 0.95
CO 2.05
HC 96ppm

I got a second hand cat and had it fitted but when I got it retested the damn thing failed again, only worse.
Low Idle:
CO 2.48%
HC 187ppm
High Idle:
Lambda 0.90
CO 5.02%
HC 146ppm

It looks like the damn cat made the emissions worse.

It was originally remapped to suit the ss system by Bob Rawle but would this have an effect?

Is the lambda sensor gone or what do I do next to whittle down the possibilities?

I'll be bring it back to my mechanic buid love to have some educated info to go back with.

Also, anyone know a place in or near Letterkenny that can test emissions?

Cheers guys.

Leonard Hofstadter

Golden rule of fixing emissions probelms - the cat is the last thing to change, not the first.

In your case the engine was running rich (taking in too much fuel for the given amount of air it's taking in), and now it's running quite rich indeed, and that is the reason the other figures are so skewed.

So fix that and see where you go from there!

dgt

Jimbob 83

Try some of that additive detergent stuff (i forget its name) on half a tank and drive the car middling hard for 30 mins before the test should pass fine

Pique

captainspeed wrote: »

Golden rule of fixing emissions probelms - the cat is the last thing to change, not the first.

In your case the engine was running rich (taking in too much fuel for the given amount of air it's taking in), and now it's running quite rich indeed, and that is the reason the other figures are so skewed.

So fix that and see where you go from there!

Ah but I didnt have a cat In the first place so had to add one.

I realise its running rich. Should I just get it detuned ya reckon?

Pique

Jimbob 83 wrote: »

Try some of that additive detergent stuff (i forget its name) on half a tank and drive the car middling hard for 30 mins before the test should pass fine

I had great intentions of doing just that too but figured I'd be ok and got held up in any case so wasn't able to do that.

Still don't reckon it would cure it myself tbh.

George Dalton

Lambda figures of 0.95 for the first test and 0.90 on the retest mean it is running too rich. The lower the number the richer it is running. So it was running too rich on the first test with the decat fitted and now it is even worse.

I don't think any fuel system cleaner will help you on this one.

Leonard Hofstadter

A properly functioning petrol engine from that era should be able to pass the NCT without the cat, especially if as you say it's been remapped to deal with the lack of the cat!

Pique

I should have said that it was tuned up a little.
It's a JDM spec S/Tb and has an upgraded turbo.
It was tuned up to 265bhp (on uk fuel).

Onwardandupwar

I personally had a couple of scoobys and evos in my day. Done all the work except mapping them myself as I'm a mechanic but speaking from experience I reckon ur failing becoz of your remap.question one is what ecu have u got in it Is it factory or apexi.if its apexi got get a standard map saved to the ecu also so you can toggle between them.if not go get your car mapped to standard again and fit the standard exhaust to it make sure all the joints are sealed right on the exhaust and get her tested again ul be fine. Oh and ps leave it on the standard map to.one final question what petrol is that car mapped for?? If you have any further questions I'd be glad to help I also know a guy how deals only in subarus if that is the route u wana go

Get yourself a bottle of Dipetane from your local motor factor or garage. Half fill your tank with fuel, follow the directions on the bottle for the amount to add and drive your car for 30 minutes before going for your retest.

Cosmo K

Ohhhhh, yeah, Dipetane, the cure for all your NCT problems. Not! You could put 10 gallons of Dipetane into the tank and it wouldn't pass. As George Dalton said, its running way too rich, you wanna go to a Subaru specialist or someone who has an emissions tester and knows how to diagnose problems properly.