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Discussion Starter #1
had my r34 tested today passed everything except emmissions

here are the figures:

low idle 720rpm:

CO 1.88vol% (limit 0.5%)



high idle 3140rpm:

CO 4.90vol% (limit 0.3%)
lambda 0.864 (limit between 0.97 and 1.03)

HC's were good at 170 ppm (limit 200 ppm)

i fitted the cat back in before the test, there is a power fc and commander fitted

is there anything i can do to get the emmissions back in line and pass

anyone have any ideas please it would be great if i could just change a few settings and scrape through :D
 

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How old is the cat as they do deteriorate over time, and gonig by your lamda readings I would say they need replacing although I could be wrong.
Just going by my last NCT my readings were:
Low idle: CO 1.04
High idle: 0.93
HC: 77ppm
Lambda: 1.067
I was running no cat in my car for the test. Also as far as I know they should not go over 3000rpm.
What sort of power are you running.Is the car running rich/lean as that will play a large part in what the readings are.Another thing you could try is stuffing the cat with steel wool and fixing a mesh in place so it does'nt blow out. Weather that works or not I dont know just what I have been told.
My NCT is comming up soon so I have ordered at cat from xforce in australia. Found it on ebay, brand new for 170aus$. Can send you the name of the person I bought it off if you need it.
Also try getting in contact with TDP and see what their thoughts are on the matter.Hope some of this helps.
 

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GTR`s struggle to pass especially if they are tuned and have uprated cams.
Ideally you want to sit outside the test centre for 5 mins with the engine at 5k rpm to get the cat really hot. You could speak to a few testing stations and explain your predicament. You may find one that can help you out.
 

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is the muffler stock?
if not you may need to block the tail pipe with an t-shirt will the probe is in and that should give some back pressure in order to get the readings down,
also go for a good blast before the test to warm it up
o yeah are you using higher octane fuel, if not you should
 

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Discussion Starter #5
the car is fairly standard, its 300 to the hubs mapped with 95 ron fuel,air filter, fuel pump,downpipe , exhaust and standard turbos,

the car was mapped in the uk before i bought it, i asked for it to be mapped with safety in mind so maybe its running rich

the lambda reading is low so i would have thought it is running rich

is it as easy as turning the injector duty down just before the test?

hodgie: i prob didnt give the car a good enough roasting before the test,will redden it the next time
 

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Discussion Starter #6
is the muffler stock?
if not you may need to block the tail pipe with an t-shirt will the probe is in and that should give some back pressure in order to get the readings down,
also go for a good blast before the test to warm it up
o yeah are you using higher octane fuel, if not you should
its a nismo exhaust with a large tailpipe, i have no bung for the end of it,might try and make something up,would a good shot of octane boost help it out?
 

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Turn the fuelpressure down to the point where the car almost stalls at idle.

Pull off a vacuumpipe from the inntake after the throttlebodys.

Here in norway we have a additive that is used to remove condensation in the fueltank, if you have it in uk, put some in the fueltank.

You should try these things, and measure the co before going back to the test station.

Asim :)
 

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My first guess is that lambda feedback is not switched on in the PowerFC, and 3140 is a tad high for fast idle test.
 

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My first guess is that lambda feedback is not switched on in the PowerFC, and 3140 is a tad high for fast idle test.
the computer decides what the rev band to do fast idle is mate :) and as said above if your car has been modified and mapped chances are it will not pass legally i do mots and am sypathetic to our type of cars but due to vosa clamping down and doing more roadside testing it can get a little harder to assist them through :)
 

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the computer decides what the rev band to do fast idle is mate :) and as said above if your car has been modified and mapped chances are it will not pass legally i do mots and am sypathetic to our type of cars but due to vosa clamping down and doing more roadside testing it can get a little harder to assist them through :)
The computer might not be able to read the revs correctly so you have to read from the rev counter :thumbsup:

And as you well know the MOT is only valid until the car is driven off the ramp, anything could have happened to it after that.
 

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Hi mate those Co2 readings are very very high bet the guys in the workshop near the car had stinging eyes, i dont reckon its anything to do with the large tailpipe on the backbox, if anything this would show up a overly lean mixture due to the extra oxygen, you may have a fcukd mass airflow sensor giving dodgy readings at fast rev speeds. Take out your plugs and check them they should be very sooted up, replace them with a good set of plugs and oh check your air filter for blockages etc this would cause a mega rich mixture reading
 

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being a ex mot tester the computer decides the fast rev speed but cant ever remember seeing it over 3000rpm, they use two forms of speed pick up the cigarette lighter cause the analyser can read the pulses from the alternator or the old fastioned HT clamp but as the might rb has coilpacks this is no good, now if the machine and sensors are not looked after the speed pick up can become erratic requiring a manual speed test. Just out of interest can you try another test station local to you as our old analyser was constantly playing up.............not to the tune of C02 like that though
 

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had my mot not too long ago,520bhp r33gtr cat put back in for mot.my readings were as follows
rpm-2731
co-0.198
hc-38
lambda-0.999

natural idle
rpm-830
co-0.292

and compared to last year not much difference
rpm-2730
co-0.184
hc-33
lambda-0.996

natural idle
rpm-747
co-0.291

no alterations made to pfc just running normal map.
 

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Discussion Starter #16
she passed :clap:

fitted two new o2 sensors and it fixed the high emmissions

thanks to abbey motorsport for helping me sort the problem and for getting the sensors fast for me, and everyone else for their input :D
 

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Congrats, you lucky ****. Hopefully after my new sensors are fitted and the small leak in the exhaust is fixed I get the same result.
 

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Discussion Starter #18
i know how you feel,i was gutted when it failed, i nearly didnt make it
i just scraped through by 0.03%vol on the high idle test

best of luck with it
 

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she passed :clap:

fitted two new o2 sensors and it fixed the high emmissions

thanks to abbey motorsport for helping me sort the problem and for getting the sensors fast for me, and everyone else for their input :D
Well done Morgan, now you can really enjoy it:thumbsup: You can always rely on Abbey:clap:

Dave:wavey:
 
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