My Volvo never ever passes vehicle emissions, help!

volvo

#1

We have a 1988 Volvo stationwagon. It always fails the “Oxides of Nitrogen”. The state standards are 2.5000 and we get 4.0477 or higher. We’ve replace the cat converter and headpipe ($560.00). Is it worth it to keep sinking money into this car? I want to keep the air clean! My husband loves old Volvos and will buy nothing else, but I’m not sure it is worth it at this rate. Suggestions?


#2

High NOx values are a result of high combusion temps. Check to make sure you are not running too lean and also check the EGR system. The EGR lowers combustion temps by recycling a small anount of exhaust gas. Check for vacuum leaks as well, as this can cause a lean condition.


#3

I hope your mechanic did not recommend replacing the converter. If so replace him. The catalytic converter does not lower NO.

The prior responder is correct, look for high combustion temperatures.


#4

Check your EGR valve for proper function and check for correct ignition timing…