Failed e test twice high NO ppm reading almost double
My 2001 hyundai accent recently failed emission test twice, as the NO ppm limit is almost double. I took this a s a sign of burning oil, so i replaced the piston rings. It needed it too, since the compression wasn't right and one of the rings ended up being seized to the piston. With a new piston rings I took it to get e tested again and failed again. I just took the catalytic converter off and it looks clean. Is there anything else I'm missing- maybe some other part of the xhaust system clogged. I would appreciate any help in the right direction. thank you
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what about the air filter is it clean ,silly question i know but you would be surprissed ,does this vehicle have one O2 sensor or two one after the cat as well or is it too old for two O2 sensors ,i know most europeon market vehicles didnt have cats till 1992 and most didnt have two sensors till around 2000 ,also check the two white or two black wires on sensor for 12v these are the heater feed wires for the sensors
Since your cat was replaced you should be looking at fuel problems...even gas cap seal....check fuel pressure,fuel regulator,and evap system.>canister or purge solinoid,o2 senser...high nox is caused by the cat or fuel problems on these engines...high pressure in the combustion chamber...lean condition>air leak on hoses,or high compression caused by carbon build up ...there is no EGR on this car so don't waste time looking for it...hope this points you to your problem
possible but could be head gasket or valves , or worn rings and is by passing the pistons going straight out the end ...or maby settings are wrong ? try carb cleaner and inspect visually air-filter etc.
A failing oxygen (O2) -sensor will give failing emission tests. Normally you also get other symptoms:
- too high fuel consumtion
- bad acceleration, stalling problems, sputtering
- the check engine light comes on indicating that the engine control
unit has recorded error codes (which will be related to readings of
incorrect fuel/air ratio when read by the OBD diagnostics tool at a
It is always a good idea to see if you can get any readings from the
check engine light if present or much better by an OBD reader to be as
certain as possible.
Another component that could cause failing emissions tests is the
catalytic converter, giving a similar range of symptoms. To determine
if this is the cause is not so easy on older cars with only one O2
sensor, it requires diagnostic skills and equipment. On newer cars with
OBDII-systems it will give a recognizable fault code for the cat
Then there are also the issues of the actual cause of malfunction in
either or both of these components, is it due to old age and normal
wear and tear or is it due to contamination from burning oil (blue tail
pipe smoke) or anti-freeze (white smoke), misfiring, etc? Then the cause must be treated as well for a successful repair.
these components have a very long life span and
should not have to be replaced more than once or maybe twice for the
sensors during the car's lifetime in an otherwise health engine.
High NOX readings indicate a somewhat lean condition IE: hot exhaust. Possible causes are cracked and leaking vacuum lines or lazy oxygen sensors. If possible have a reputable garage with engine electronics scanner services check the sensor to see if its helping to create the lean condition
have you had the the engine codes pulled and reset?
and if so what are your engine codes?
i dont know of any car that will pass emissions test with the engine light on.
we cure your trouble that caused your engine light to come on and you will pass your test.