High emissions at idle

J

jameswrx2

Member
Just taken my car for an MOT and it would have failed the emissions at idle. I say 'would' becuase I managed to lower the HKS AFR so that it passed.

It only passed that even because it was on the pre 1995 Import loophole.

The emissions at idle reading was 4.5

It should be 0.30 I beleive but the import loophole means it can go as high as 3.5.

Even when I adjusted the HKS AFR right down it would only go to 2.20!

The fast idle was fine (even before I adjusted the AFR) It was just the idle that was high.

I have a cat fitted (did this saturday in prep)

I'm thinking it's probably a lambda issue, any thoughts? I think the fact it was fine at fast idle and only rich at idle has something in it which may point to specifics (I just need someone to point :D )

Oh and the car failed the MOT in the end on a split steering rack gaitor! That was the only problem.
 
Fusion Ed

Fusion Ed

Active Member
Ok couple of thoughts.

First lambda sensor as you said. It may need replacing and can be shown how well its working when put under a consult test etc.

Secondly the cat was it hot? Often at idle there is not enough exhaust gasses to get the cat upto full operating temperature. Usually its best to take the car for a quick drive before you do this.

Finally, was the cat bolted on the right way round? As crazy as this sounds it does make a difference. The exhaust gasses have to pass through the cat in the correct order for it to work properly.
 
J

jameswrx2

Member
Hi Ed.

Cat was hot. I'm pretty sure I put it right way round, to be honest I didn't think it would go both ways because of the opposite angles at each end on the flanges. I suppose I could have got it upside down and round the wrong way.. but then the COF sensor wiring wouldn't have sat right, so pretty sure it's right.

I've been doing some more reading on here and noticed the MAF re-ground can sometimes sort it too, so I'll do that anyway.

Does anyone know deffinatley what a UK sunny GTi-R reading at idle should be? I read 1.00. The tester told me 0.3.
 
campbellju

campbellju

Moderators
Staff member
I'd go with the lambda sensor too, its fairly typical symptoms. Re-ground your MAF if you've not already done it anyway.
 
gtirx2

gtirx2

Active Member
Are you running a adjustable fuel pressure regulator?If you are maybe you have the fuel pressure up to high?
 
antgtir

antgtir

New Member
Sounds like it could be a Lambda sensor however the best thing to do is find someone who can test this for you i.e. with the ConZult package, that way its not a wasted purchase. Although tbh ive been told these are pretty much consumables on the R lol.

If you find a reasonable place that sells the Lambda for the R let me know as i think i may need one to :rolleyes:

Ant.
 
J

jameswrx2

Member
To be honest if it's the lambda I'll get one from Nissan I reckon. You can obviously get the universal ones but I'm not keen on cutting the wires and splicing the old plug on for some reason. I did it on my Impreza but it just seemed a bit bodge.

I presume it's a Nissan job for the consult.

I think Nissan charge £86.. but then again if that's +vat there is a website selling them with the Nissan plug etc for £83 inc delivery so may go there.

I've no plans to sell the car for a while and I've been replacing bits that don't exactly need doing so a fresh o2 sensor may as well be added to the pit.
 
antgtir

antgtir

New Member
Yes i think thats about the price. Im sure it will be +vat.

The ConZult is something you can buy yourself to aid in future diagnostics, find it on ebay under BlaZt, its £80 but does a hell of alot and your bound to need it more than the once lol. Link as below : -

http://cgi.ebay.co.uk/BlaZt-ECU-Cab...ryZ72205QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

Same here with the replacement of parts, never like to stray to far away from the OE parts tbh, i always feel the quality is superior unless of course you find somewhere that makes them for Nissan and just adds a stamp lol.

Ant.
 
Fusion Ed

Fusion Ed

Active Member
Also another note the GTIR doesn't use a normal universal style sensor, the Nissan one outputs slightly higher voltage so a normal OEM wouldn't work
 
Jonesy

Jonesy

Member
I was looking at wideband and you can get a wideband set up that also sends the narrowband signal to the ecu, maybe worth doing that if you were thinking about wideband anyway.
 
antgtir

antgtir

New Member
I was looking at the wideband option, like you say you can get some that send the narrowband signal to the ecu but with the wideband also gives you more tuneability, am i right?

Ant.
 
Jonesy

Jonesy

Member
Yip thats right, just thought if you were going to have to pay out £90 or so for the lambda sensor, maybe worth paying a bit extra and getting the wide band to. For tuning and monitoring the air fuel ratios.
 
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