|
|
|
|
Junior Member
|
|
Feb 9, 2014, 11:34 PM
|
|
Emission test failure
I have a 1999 chevrolet cavalier 2.4L DOHC 4cyl, that has failed an emissions test twice. I've changed the air filter, and spark plugs. Also I connected an OBD2 reader and it came back zero codes, and the check engine light is not on. So if anybody has any info on why it failed.
|
|
|
Expert
|
|
Feb 10, 2014, 04:10 AM
|
|
Why did it fail ? When they give you results, what readings were out of standards
|
|
|
Uber Member
|
|
Feb 10, 2014, 06:18 AM
|
|
Exactly... nobody can offer a guess without knowing what it failed for... what its readings were measured at and what the acceptible range is for where you live. You would have been given a printed report by the inspection station.
|
|
|
Cars & Trucks Expert
|
|
Feb 10, 2014, 02:06 PM
|
|
I'll take a guess (since I've actually had to deal with these issues)
You probably had to sit in line waiting for your turn and the catalytic converter cooled down enough to lose efficiency. Next time, when you see it's nearly your turn up, rev the engine to about 15-1800 RPM and hold it there. That high-idle should be enough to 'wake' the converter and then you should pass your test.
Let me know what happens, k?
|
|
|
Uber Member
|
|
Feb 10, 2014, 03:50 PM
|
|
The catalytic converter is likely marginal and needs to be replaced. It may have been destroyed by a failing Ignition Control Module (ICM), which allowed raw gas to contaminate the converter. I recommend replacing ICMs every 125,000 miles or 10 years, whichever comes first. Failing ICMs often don't throw a code.
|
|
|
Junior Member
|
|
Feb 13, 2014, 12:14 PM
|
|
Emission test fail
First emission test: 15mph NO(ppm) MAX 459, AVE 67, MEAS 897 (FAIL)
25mph NO(ppm) MAX 746, AVE 62, MEAS 167 (PASS)
Second emission test:
15mph NO(ppm) MAX 459, AVE 67, MEAS 587 (FAIL)
25mph NO(ppm) MAX 746, AVE 62, MEAS 14 (PASS)
So with this info can anyone tell me what the problem might be?
|
|
|
Uber Member
|
|
Feb 13, 2014, 01:43 PM
|
|
Among the potential causes of non-compliant NOx readings are:
. Misfire condition--think plugs, plug gap, and ICM failure.
. Malfunctioning or improperly adjusted EGR valve.
. Failed oxygen sensor.
. Leak in exhaust tubing upstream of converter.
. Excessive carbon deposits in combustion chamber.
. Improper spark advance.
. Blocked coolant passage.
. Overly lean air-fuel mixture.
. Damaged cold air duct.
. Failed or malfunctioning catalytic converter.
. Corroded or damaged engine sensor electrical connections.
|
|
|
Junior Member
|
|
Feb 13, 2014, 02:24 PM
|
|
Originally Posted by 7up
First emission test: 15mph NO(ppm) MAX 459, AVE 67, MEAS 897 (FAIL)
25mph NO(ppm) MAX 746, AVE 62, MEAS 167 (PASS)
Second emission test:
15mph NO(ppm) MAX 459, AVE 67, MEAS 587 (FAIL)
25mph NO(ppm) MAX 746, AVE 62, MEAS 14 (PASS)
So with this info can anyone tell me what the problem might be?
So how does the emission test fail at 15mph and pass at 25mph?
|
|
|
Uber Member
|
|
Feb 13, 2014, 03:42 PM
|
|
A failing ICM, which shows up at low speeds in your case, could explain it.
|
|
|
Junior Member
|
|
Feb 13, 2014, 09:50 PM
|
|
Emission Control System test
Pvc,catalytic converter,fuel injection,vacuum line connections,fuel cap functional,MIL,ignition spark controls,O2 sensors and connectors,other emission related,fuel evaporative controls,fuel tank cap visual,wiring of other sensors or switches,liquid fuel leaks.ALL OF THESE PASSED
(N/A:)VISUAL EGR,FUEL EVAP TEST,THERMOSTATIC AIR CLEANER,AIR INJECTION SYSTEM,FUNCTIONAL EGR,FILL PIPE RESTRICTOR, CARBURETOR,IGNITION TIMING:TDC
SO IT COULD BE THE( IGNITION CONTROL MODULE?
|
|
|
Uber Member
|
|
Feb 14, 2014, 06:13 AM
|
|
Reflect on whether any of this fits concerning your ICM:
When not replaced, vehicle could experience no- or hard start, long crank time, misfire, lack of power, inconsistent transmission shift points, spark plug fouling, catalytic converter failure, poor fuel economy or CEL/MIL illumination.
Make sure the intake manifold gasket does not leak. This could cause a lean air-fuel mixture.
Personally, I would make sure the ignition system is perfect. This involves the ICM, coil packs, plugs (AC Delco only), plug gap, and spark plug wires. I would replace these items, if they have been in for 125,000 miles or 10 years. Only you can tell if the car is worth replacing these items.
Another area you definitely want to check out is the Exhaust Gas Recirculation (EGR) System. This system keeps NOx levels lower by reducing the temperature of the fuel mixture. Consider replacing the valve, gasket, and hoses.
|
|
Question Tools |
Search this Question |
|
|
Add your answer here.
Check out some similar questions!
Emission test cannot communicate with vehicle
[ 6 Answers ]
Brought my 2004 yukon for new sticker. It failed emission test . It cannot communicate with the obc. I was told to drive it for around 50 mi which I did . It failed again. Then was told there was now power at the connector under the dash. Changed the bat about thee mounths ago,no check engine light...
Emission trouble
[ 2 Answers ]
I have an 89 buick lesabre with a 3.8L engine.is there someone who can tell me which part of the emission system controls the (HC(ppm),CO(%) ) thank you
Re-set computer in saturn engine to pass emission test
[ 3 Answers ]
Are there specific steps in resetting the computer in a Saturn engine? I was told to drive 100 miles to re-set computer. I have now driven 500 miles. I went 4 times to garage and still get engine not ready for testing.
Thanks for anybody's help.
Failed Ontario Emission Test
[ 4 Answers ]
I have a 1993 Toyota Pickup, 22RE I4 engine with EFI. 300Km... Good compression,no oil burning, 5 speed manual.
FAILED HC Test limit 66ppm reading 209... PASSED HC Curb Idle Test limit 200/ 129
FAILED CO% limit 0.37 reading 8.34... PASSED CO% Curb idle limit1.00/0.18
PASSED NO limit 968 reading...
View more questions
Search
|