Excess unburned hydro carbons can be difficult because the cause can be both engine oil and fuel related - even low quality engine oil can be a factor, especially if the car is used for lots of short journeys.
Considering the age of the car there could be some oil consumption issues, principally from the valve stem oil seals, blocked or inefficient crankcase breather or piston ring/bore wear.
Poor fuel injector spray patterns producing a too-large droplet size can increase the amount of unburned fuel as can a leaking injector.
SOURCE: ASM 2525 NO ppm TAILPIPE EMISSIONS failure
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.
later
paul
SOURCE: volvo 850 wagon failed NOx emissions test - badly!
Hey Pitloops!
It seems likely that one or both of your o2 sensors are acting up, or that your engine is sucking in unaccounted air from a leaking vacuum tube. Spray the tubes with "start gas" while the engine is idleing. If you hear it revving up when you spray the gas on the tubes you'll know there's a leak.
I'll sacrifice a squirrel for you and hope that the problem isn't your o2 sensors since they can be expensive to replace. Fcpgroton.com is probably the cheapest part supplier online if you'll need new sensors.
You might also want to clean your throttle body, as it usually gunks up with carbon deposits and sludge over the years. It only costs you the price of the carb cleaner to do it and the car will probably run better afterwards even if it doesn't solve the problem.
Good luck!
SOURCE: FAILED EMISSIONS
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.
SOURCE: 1993 S10 Chevrolet Blazer DID
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
SOURCE: My 1997 Honda Civic failed
Jose, I don't know if this will give you the answer you are looking for because there are many things to consider here. The exhaust gas recirculation valve (EGR) is one of the main things involved in reducing NO emissions. This valve is controled by the power control module. (PCM) This is your vehicles computer. The PCM monitors the vehicles speed and will command the EGR to open when the vehicle attains a certain speed, which is why the ASM test being done is recorded at two different speeds. At 25 MPH your vehicle failed the hydrocarbon (HC) emissions limit and this could be for a number of reasons. When is the last time you car was tuned up? Old spark plugs, wires, clogged air filters, oxygen sensors, leaking injectors (personal experience) or the PCV valve could be contributing to the results of the test. I guess that the easiest way to go is to tune up the engine replacing the spark plugs, wires, air filter and the PCV valve and don't forget to have the oil changed at the same time. Only then should have the vehicle retested and see what the results are. Should it fail again you may have to consider having the EGR or the catalytic converter replaced depending on what portion of the test fails. If the NO fails I would consider the EGR. If the HC fails then I would consider the catalytic converter. Good luck with this.
171 views
Usually answered in minutes!
×