What cause high NOx emissions?
High NOx levels are normally caused by high combustion temperatures and pressures, slightly lean AFR, and excessively advanced ignition timing.
Why does my Jeep 4.0L have high NOx?
While the columns did deal with a driveability problem on a Jeep 4.0L, the problem was entirely different from what your customer is experiencing. Second, a lack of backpressure caused by the aftermarket exhaust system should not cause an increase in NOX, at least not on a vehicle that’s capable of adjusting its own air/fuel ratio.
What makes a Jeep Wrangler fail a smog test?
NOx was the last addition to the list of monitored exhaust gases. Misconceptions regarding the conditions that promote its formation still exist. I am working on a 1995 Jeep Wrangler with a 4.0L engine that has failed to pass a smog test due to high NOX.
When does the EGR system cause high NOx?
The EGR system’s job is to re-route a small amount of exhaust gas back into the intake manifold to help reduce combustion chamber temperatures. As mentioned above NOx is created when combustion chamber temperatures reach above 2500F.
What to do if your car fails the NOx test?
If you own a non-EGR equipped vehicle, and have failed the emissions test for high NOx, pay close attention to the Catalytic Converter. Read about Catalytic Converter
While the columns did deal with a driveability problem on a Jeep 4.0L, the problem was entirely different from what your customer is experiencing. Second, a lack of backpressure caused by the aftermarket exhaust system should not cause an increase in NOX, at least not on a vehicle that’s capable of adjusting its own air/fuel ratio.
NOx was the last addition to the list of monitored exhaust gases. Misconceptions regarding the conditions that promote its formation still exist. I am working on a 1995 Jeep Wrangler with a 4.0L engine that has failed to pass a smog test due to high NOX.
Can a car control NOx without an EGR valve?
Automotive engineers must agree because many vehicles now manage to control NOX without the help of an EGR valve. The Jeep you’re working on is one such vehicle. But everything else must be working properly if the EGR valve crutch is removed.
What are the NOx levels in my car?
I also installed a NOX-reducing cat. After these changes, it barely passed the 15-mph emissions test and still failed the 25-mph test for NOX. The exhaust readings at cruise are as follows: CO, .01%; HC, 12 ppm; CO2, 15.0%; NOX, 917 ppm.