hi all,
posted up the other day about failing the mot...just a re cap..took out lambda
cleaned it with carb cleaner put back in ,then took the car back to the garage
go nice and hot co was lower ...but hc was 3888 ..wtf still high hc talking to the guy there .he reckons its not burning the fuel properly in the chamber which is causing the high hc emissions...its down to my spark plug gaps so the gaps are set at the moment to 0.6m
because of the higher boost..i have ngk 6s in at the moment...so want im going to do is take them out and regap them to 1.0mm as recommended by subaru..then put some 99 ron in and booster ...ill let u know on the emissions
test .....soon fingers crossed

 

1mm? seriously?

 

wont make any difference

 

right all ...good result gapped plugs to 1.0m...and passed emissions no problem...with a full decat tooo hc 137 engine no longer lumpysmooth as a babys bum...so if your engines lumpy..

1.check for ecu fault codes first ..if no fault codes..fine
2.if engine still lumpy...change all 4 coil packs for brand new ones.
3.gap plugs to 1.0m .all plugs are preset anyway..check first
4. enjoy

 

that sounds a bit strange? just guessing but making the gap larger would make the sparks jump and fire slower and increase the amount of unburnt fuel in the engine? yes/no?? unless the ecu has learnt that the car is running slower and not pumping nearly as much fuel through the engine. have you noticed any lose in performance? i know you may be misslead as its not lumpy anymore and is now smooth.

i had jap plugs in my car as it was imported and had to get ngk alternative. first set i was sent the gap was 1.0mm and the car ran fine until you got to 5000rpm then it spluttered like mad. also backfired a few times at high revs. after moaning to surplier they sent correct plugs and runs smooth all they way through.

my emission are 7.9, 4.2 and 2.8 if i remember correctly. but shhhhhh lol

 

hi... no ..the smaller the gap =more unburnt fuel.. hence the high emissions.
i could see what was going on in the chamber via the readings on the gas analyzer..low co2 and high hc =unburnt fuel...my cars mapped for 97 ron with a scoobyecu and now boosts to 16psi with no hesition at all.
if ur car is running like crap its the coilpacks and or ur gaps. try it and see for urselfs. good luck all.. at mot time

 

hey may just try some of those things you have done i have had the same problem.

my 93 import has failed mot on same s**t it failed big time so i have changed lambda put original system back on and still failed.

so your saying you have changed coil packs,open your plugs up?????????

 

IF U HAVE A DECAT EXHAUST LEAVE IT ON.
GAP PLUGS TO 1.0M
IF U MISSFIRE AFTER CHANGING GAPS TO 1.0M..AND IT RUNS LIKE A BAG OF **** THEN BUY NEW COILPACKS ...HAS THEY WILL BE FAILING...CAUSING HIGH EMISSIONS= **** SPARK, GOOD LUCK LET ME KNOW..

 

it depends on year of car of cause as if you have a 93 then you dont have to pass the latest MOT emissions test and only have to pass the BET standard which is just a idle running reading. mine runs fine at idle and only has the silly readings when its reved. you dont even need to have a CAT fitted as it isnt an MOT requirement. there are lots of other threads on here as i asked before when mine failed MOT.

 

will give it a try and let you know.

cheers

 

yes i have a 93 and it is just outside the limit when on idle.

 

hi guys been down to alan jeffery got me car nearly sorted its turned out to be MAF and the new LAMBDA f**cked so its turned out a pretty expensive repair.

thanks for all ya advise but not that lucky to just be that.

cheers