What causes High NOX Emissions Please note that while a failed catalytic converter will contribute to high NOx readings, the failure in itself may have been caused by some other upstream performance problem. In all cases, it is crucial to identify the root cause of the problem before blaming the converter. Case Study
Thousands of technicians have faced the challenge of bringing a particularly stubborn application into compliance for NOx emissions. High NOx readings are a clear sign of performance issues somewhere in the system. The question is, where?
Among the potential causes of non-compliant NOx readings are:
Misfire condition
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
SOURCE: 1992 dodge stealth failed smog test with high NOx
NOX is produced when cylinder temperatures exceed 2500 f.
Your vehicle has 2 ways to directly reduce NOX, EGR system, and catalytic converter, and also the cooling system indirectly.
Take a look at the EGR system, vacuum lines, pipes, and make sure the diaphragm moves. Disconnect the vacuum line, then push on the diaphragm and plug the hole (from vacuum line) when you release the diaphragm there should be vacuum. Also you may want to take it out and give the EGR passages and EGR valve a good cleaning, with some type of carbon cleaner like carb cleaner.
SOURCE: engine code 95 jeep grand cherokee lerado
12 is a battery disconnect within the last 50 start cycles and 55 means the end of the diagnostic cycle. Basically the computer found nothing wrong. The 12 code may seem incorrect if you haven't disconnected the battery recently, but from my experience the 12 code shows up almost all the time regardless.
SOURCE: Our 1991 Toyota Corolla failed
yes the cadallac converter produces nox emissions i would say the cadallac is on its way out
the caddalac is on the exuast
SOURCE: 1993 Jeep Grand Cherokee, V6. Oil Pressure Gauge Read High.
it could be the sensor you should look at the oil pressure relief valve
SOURCE: 95 Jeep Grand Cherokee ''overdrive'' light
I would recommend taking this to transmission shop or the dealer, sounds like there is an internal problem with the transmission.
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