gc8 help needed

R

Ross3k

New member
i am trying to get my 96' jdm wrx through the nct but emissions are high car is running really rich.

i checked my 02 sensor voltage readings there wasnt much fluctuation (staying around .2volts) so i took it that it was dead, i fitted a new aftermarket probe and it is now reading around .9 with fluctuation to .1 volts when revved.

I also fitted a stanard full turbo back exhaust with two cats in it but my emission readings are still super high

anyone any ideas, seems to be overfuelling but i cannot figure out why ?

car has a standard ecu in it. it has a aftermarket air filter and did have a hks downpipe and full decat exhaust but i changed it for the standard exhaust for the test. would the ecu need to be reset to adjust for the changes with the exhaust ?


thanks in advance..
 
You check for Air leaks on the intake and before the lambda on exhaust?Also should be only 1 cat in the down pipe, is it a known functioning one?
 
[quote author=BazGF8 link=topic=41248.msg472125#msg472125 date=1395758705]
You check for Air leaks on the intake and before the lambda on exhaust?Also should be only 1 cat in the down pipe, is it a known functioning one?
[/quote]

cat is meant to be good and my hc readings on the emissions tester seem to be telling me they're working.. i've been looking for vacuum leaks but couldn't find any, one thing i noticed is there is a bov fitted (looks like a bailey one) when i rev the car only a little i can see the spring moving in it and when driving at cruising speed (not on boost) and slighty lift the throttle i can hear it making noise, could the valve be f**ked or spring tension too loose be causing a vacuum leak ?
 
[quote author=BazGF8 link=topic=41248.msg472127#msg472127 date=1395759056]
Yep fit standard one to be sure
[/quote]


would if i could, previous owner fitted bov so no standard one to put back on..

can anyone confirm that the piston inside the bov does or doesn't move when blipping the throttle i.e only to 2-3k revs
 
[quote author=Ross3k link=topic=41248.msg472137#msg472137 date=1395764241]
[quote author=BazGF8 link=topic=41248.msg472127#msg472127 date=1395759056]
Yep fit standard one to be sure
[/quote]


would if i could, previous owner fitted bov so no standard one to put back on..

can anyone confirm that the piston inside the bov does or doesn't move when blipping the throttle i.e only to 2-3k revs
[/quote]

Get one of a breaker?
 
Might do, I just don't want to keep throwing parts/money at it if possible.

I'm showing rich readings on the 02 sensor, when I introduce a vacuum leak at the manifold it shows low readings as it should, this makes me think vac leak and/or bov are not the problem, it's just running super rich for some reason. :banghead :banghead :banghead
 
afm, tps, 02 sensor all testing ok.. i am now thinking its possibly the temp sender that is causing overfueling by telling the engine its cold when its not, if i disconnect the sender and run the engine i get the same rich readings as when the sensor is connected, this makes me think the sender is doing nothing and the engine is permanently running in "cold/warm up mode" with high fueling and because the sensor isn't telling the ecu when its warm therefore the ecu doesn't pull back the fueling. I'll test the sensor later for resistance if i can get to it..
 
[quote author=scubbay link=topic=41248.msg472295#msg472295 date=1395849316]
A smoke test would answer a lot of your questions
[/quote]

I've had it tested 3 times in the last 2 weeks.. The mechanic just said it's running far to rich ?
 
so temp sender tested ok,

FPR tested ok too.

had it back on the smoke test today

c.o 9.99

lambda too low

HC way too high

only way i can get them down is by introducing a vacuum leak.. i disconnected the o2 sensor to see if made a change to readings and it didn't no difference at all, o2 voltage is always high, at cold, warm, hot the voltage reads around .9 with a slight fluctuation
 
either overfueling or misfiring.
leaky injector? timing? leads plugs coil
does O2 reading drop when vacuum leak introduced? if so sensor ok
 
[quote author=seanie link=topic=41248.msg472416#msg472416 date=1395921524]
either overfueling or misfiring.
leaky injector? timing? leads plugs coil
does O2 reading drop when vacuum leak introduced? if so sensor ok
[/quote]

yea defo overfueling, can't seem to find a leaky injector, o2 sensor reading drops when vac leak is introduced.. seems to be firing ok, removed plugs and they were just showing signs of running rich (black & sooty)
 
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