jap-sti-555

hi had emissions done and results are as follows, if anybody can shed some light to what my problem is it would be fantastic. thanks in advance to all of you!.....

fast idle test
co 3.71 %
hc 120 ppm
lambda 0.91

second fast idle
co 4.62%
hc 150 ppm
lambda 0.88

natural idle test
co 7.18 %

failed test uite bad, any ideas to resolve??

Brit_in_Japan

Your CO emissions are much too high. IIRC lambda should be between 0.97 and 1.03, so it looks like your lambda sensor is duff which means you are getting too much CO.

Replacing your lambda sensor would be a good first step!

jap-sti-555

thanks for the advice, where is the location of the lambds sensor? never had to change befor.

AndyLyman

iTrader: (1)

I think there are 2 sensors mate...

1 is at the front on the manifold as is very expensive... just had my new one fitted at a cost of £350 on my 02 UK Sti...

The 2nd is in the centre pipe of you exhaust...

hope this is of some help...

Andy

scuba_doo

All the results show that it's running rich . The lambda as said above should be between .97 to 1.03 , with it on .88 means running rich also with the co that high also running rich and hc's again say's there's to much unburnt fuel .
I take it the cat's are in place ?There is no missfire ? has it been mapped ?
has the fuel pressure been raised ? is the airfilter clean . Also if the cats are fitted then with it running like this it's quite likely to smell of rotten eggs , thats if the cats have'nt already had it .

jap-sti-555

mine is a 1996 sti and i thought this sensor was only about £60. is the location under the drivers side? im confused about the whole thing still.

jap-sti-555

i only have the 1st cat in place (down pipe cat) the other has been removed due to new exhaust. was told this should still pass with just the one, is this the case? i did have a remap but have fitted front mount intercooler since this.

scuba_doo

After fitting a fmic , think you would need the mapping adjusted to suit the changes . I'm an mot tester and was a diagnostic tech and as i said above from the readings it's running to rich for some reason . First steps i would take is to check airfilter and also maf as i believe these are prone to problems , if the maf is reporting a to higher airflow then actual ,the engine ecu will inject more fuel to keep the mixture correct which would then send the lambda down and the co and hc's up . Also did you have any of that dodgy fuel from tesco's as that messed with lambda sensors !

jap-sti-555

no not had that fuel. how do i go about getting these checked out? i had diagnostics done already and it did show lambda fault. would fitting new lambda fix the problem or is there still something more to it like you said?

Brit_in_Japan

Lambda sensors sense oxygen content in the exhaust gases. The ECU adjusts timing to make sure that the emissions are within the limits set by regulations. Someone else might know more about the lambda sensor on your model and give you more advice, I've not had a problem yet so haven't needed to change one.

Cars can pass emissions tests with only one catalytic converter, but that doesn't mean they will pass. The manufacturers would try to use the cheapest solution for passing emissions tests so why would they put in an extra cat costing £££ if they didn't need to? If you take one out, you might well fall foul of the emissions tests. As a minimum everything else would have to working properly, air filter, MAF etc, but if a car has been remapped then it's really down to the mapper to make sure emissions tests can still be passed. Some people change exhausts back to standard items for the MOT and then change back to their big-bore, de-catted, ear-drum splitting mega zorst afterwards, though it's a dubious practice as a car should be capable of passing an MOT at any time, not just during the test.

Edited to add: if you've fitted a FMIC since you had it mapped then it's not the mapper's fault it doesn't pass emissions. Sounds like you need to get another mapping session planned !

scuba_doo

You really need to book it in for a diagnostic as guessing it's the lambda could cost you between £50 to £100 for a sensor and so on if it's not that,unless you have a mate that does'nt mind swopping bits with yours till you find the cause . But check the basics first like the airfilter and fuel pressure are not blocked and pressure is to high, and also a maf sensor is a few seconds to swop over .
Did it pass last year and if so what was the emissions readings then and what's been done to it since ?

Alan Jeffery

The lambda sensor should be checked at this point. The difficulty is in determining the correct wire to check as the colours are different from UK and Jap spec. There are three wires. One earth and one 12v for the heater, and the signal wire. The signal wire is usually white on the car side of the lambda multi plug. With the engine running and up to temp you should see it moving between .1 and .9 of a volt if everything is fine. That shows the sensor is cycling, and keeping the mixture correct. If it sits at around .9 of a volt all the time, the sensor is fine, but the mixture is too rich for some other reason. If it's showing .1 of a volt all the time, the mixture is weak.
Got that?
Now, if the sensor is showing around .5 of a volt all the time, it's duff.

Alan Jeffery

By the way, the early cars are quite happy with an after market three wire lambda ( two whites and a black ) at about £30. Black goes to white on the car, and the other two can go either way!