Can an exhaust leak cause high NOX?
An exhaust leak CAN change the reading the O2 sensors gets, and cause a corresponding leaning out of the mixture, which would cause high NOX.
What causes high HC emissions?
Ignition defects including dirty spark plugs, leaking or open-circuited spark plugs or wires, or defective ignition coils can all result in a shortage of spark energy. Any shortage of spark energy may cause high HC emissions. If the spark occurs at the wrong time, incomplete combustion and high hydrocarbons may result.
What to do about Honda engine hunting idle?
The most important part of the procedure is to back it off 1/4 turn after you bottom it out. You won’t find one of these on EVERY Honda engine BTW, mostly on engines older than 1997. The later model engines just use the IAC to control fast idle on a cold start up.
When was the last time Honda idle issues were addressed?
This topic contains 9 replies, has 7 voices, and was last updated by Ariel 6 years, 11 months ago. PLEASE READ THIS FIRST BEFORE POSTING ABOUT HONDA IDLE ISSUES!!
Why does my Honda Civic idle too high?
When cold you just get an idle that is too high like up around the 1200-1500rpm range or higher. The second video shows a vacuum leak that I found on a Civic using a ‘safer’ method for checking for vacuum leaks. Both work but the important thing is that you check for vacuum leaks if you have a Honda idle problem.
What’s the base idle rate on a Honda Accord?
Depending on the model you normally unplug the IAC after the engine is fully warmed up and adjust the idle screw until you reach base idle which is normally in the 700-750rpm range. This will often set a CEL so you’ll need to reset that after you’re done.
Why is my NOx reading so high at idle?
Adding a load pushes the combustion chamber temperature to the point where NOX formation increases to an unhealthy level. The engine should be producing almost no NOX at idle. If the NOX reading is high at idle, run through the NOX-influencing factors I’ve listed until you find the cause.
Why does my Jeep have high NOx levels?
As you correctly surmised, combustion chamber deposits can artificially raise the compression ratio and encourage the formation of NOX. Overadvanced ignition timing can also cause NOX formation. Since the Jeep does not have an externally adjustable ignition system, we should be able to rule it out as a possible cause in this case.
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.
Why does my GM MPFI fail NOx test?
GM MPFI 3200, 3800, engines failing NOx caused by lean condition. General Motors Multiport Fuel Injection engines may fail emissions standard testing due to excess Oxides of Nitrogen levels in the exhaust gas. Here are some steps to determine and correct the cause of high NOx emissions.