Natural Idle Test Results...Help plz
 

Hi, car is just back from its MOT and it has failed on its emissions. Garage has tried their best by testing it on the "easy" test, but the car wont pass on the natural idle test.
Car is a '94 WRX with Scoobysport Downpipe and Sti exhaust, it has also been remapped using the scooby ecu. Results were as follows:

CO: Limit <=0.50% my car: 1.92% :(

Does anyone have any ideas on what to do? Is there a chance that it could be a sensor that is faulty as I dont want to have to think about replacing downpipes or center sections etc. Thing is it seems to be on idle that its a mile out as the other results wernt to bad:

<b> Fast Idle Test:
Engine Speed: 2500-3000rpm
CO: <.30% Actual=.41%
HC: <200ppm Actual=57ppm
Lambda: 0.97-1.03 Actual=1.01
</b>

Thanks

Dougie

Possibly a Cat (assuming the centre one is still fitted) or lambda problem.. might also be worth reconnecting J1 so it runs the standard ecu map.. incase it is leaner on idle (no idea if it is or not but worth a try).

Either that or refit downpipe with cat in..

JGM :)

should be fine on scoobyecu but lamda sensor issues may cause problems

earthing of sensor as well as the sensor itself. Dnb added a dedicated earth from body of sensor to ECU, this was required even with a new sensor

Paul

LOL

Just re read you don't have a CAT of any sort, it wont help!

Paul

hi if you dont have any cats at all it will fail full stop! so you have to put a cat in or i know some people who do special mots ........

JGM, u must have been reading my mind, have just replaced J1 and put in some injector cleaner as well. Thing is these results look almost identical to the results I got when the car had the standard downpipe in it?

Pavlo, am i right in thinking you were one of the guys that started ScoobyECU? It was Scott T that I dealt with, had a look at the ECU while it was out, it is the prova version3 chip that is in, think it had a target boost of 16.5psi, any other info on this map that could point to possible idle running rich?

Are there any idle sensors that could be faulty that are causing the run-rich-mixture?

Cong are you positive that it wont pass if there are no cats on it? Should be able to make <.50% CO on idle, even with no cats????????

Cheers

Dougie

Ps Cong know a few of those people myself :D

most cars wont pass the emission test unless they have at least one cat escpecially the scoob can you imagine a subaru passing a co test with out a cat the amount of co produced are quite high compared to most cars i think, remeber our cars are gas guzzlers

here you here is what i found about the cat

http://www.ask.co.uk/ix.asp?q=what+d...c%2Ehtm&adurl=

sorry forgot how to shorten it to a clicky thing, just copy paste

also explains why you should decat a car looks like the exhaust has to pass a brick wall, giving you lots of back presure therfore slowing zi turbo down and making less boost!

so the cat convertor must change those co into co2 hope thi explain why most cars will fail the mot with out a cat, but then agin my civic vti was fully decat and passed, but you have remember its only n/a so therefore the amount of fuel being burnt isnt alot plus you have to remember the subaru is supposed to be runing slightly rich to help the engine last longer

Top :(

No idea why you are putting it back to the top?

You need at least one cat, as Pavlo has said it appears you have none? It will NOT pass without a cat.
Pavlo has then pointed towards the Lambda sensor if you have a cat fitted and it still fails?
Or the other way around in fact..

It is then suggested that you could perhaps go to a special mot place and you say you know some people like that...

So either fit a cat/and fix the lambda or go see you special mot place.. really confused as to why you feel you have not had an answer????

JGM

yep like evryon said jgm

exactly... the answer is under his nose and he cannot see it?!

JGM :)

I can see it mate, problem is that the results were almost identical to the results I had when i had the cat on it! That is why I am lookin at the possibility of it being something else instead. I asked Pavlo for some info on the Prova map, that is why I put it back to the top, sorry if it annoyed you, but I was wantin info from Pavlo.

If you had both read my posts properly you would have seen that I recognised the answers you gave me and thanked you for them.

FFS

Dougie

are you saying that with the decat you getting high results and with the cat on your getting the same results? ............if so it would mean the mot gas analyser machine is not working properly or your cat convertor is damaged

I was not annoyed just amazed that you had been answered but were still not seeing it..

the results are only slightly higher because the CAt doesn't do a huge amount on idle.. but does drop the emssions into the pass zones..

JGM

Just seems as tho you both think Im not listening to what you have said by putting it back to the top.

Cong so there is no confusion. At the last MOT, the car had a downpipe with the cat in it, it still had problems passing the MOT on its emissions. Not a case of tested it, with a cat, then, without a cat, within a short space of time on the same machine.
This time there is a Scoobysport downpipe(catless obviously) and from what I recall the emissions are not all that dissimilar to when it had a cat on it.

This is why I am wondering if there is maybe somethin else that could be done to get the car running leaner on idle. Like replacing J1 (which was suggested and aknowledged and since been carried out). What I was trying to find out as well was which sensors give the readings at idle so that the ecu can adjust accordingly? I am trying to get this info from Pavlo,in relation to the scobbyecu to see if there is maybe a faulty sensor that could bring it down as well. As it seems to me from the results that the biggest problem is at idle, not at fast idle which I would have thought would have been the case if the car is catless.

All this is probably going to be irrelevant anyway as it seems the car should get a default test which is not as stringent and going by my results it should pass.

Dougie

Only sensor it monitors that would effect idle emissions directly is the Lambda in the downpipe, although in your case it might be in the headers.

Pavlo confirmed that the Scoobyecu idle set up should pass an mot.. I was unsure before he said that if it altered them from standard or not.

JGM

try placing the centre cat back in even with one cat in place it should pass unless the downpipe cat is faulty get your car on a rolling road to get the emission results did you have a cambelt done? spark plugs replaced? check ecu fault code looks like you might be runing rich, get your idle adjusted you say it was remapped? is there anyway to check your mappings you have done to the car............if all fail put all the cats back in and then goto to a new mot testing garage and see if you get different results

Dougie

JGM thats what I was needing to know Thnx. Was unsure if any other sensor other than LAmbda was involved in the process.
Cant put any cats back in Cong without buying them, downpipe that was taken out was fooked n the car is an Sti so its got the STi stainless exh on it (no center cat).

Promise I wont post onthis thread anymore ;):D

Dougie