My Volvo never ever passes vehicle emissions, help!



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?


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.


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.


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