I own a 97 850 glt wagon. The car passed smog in 2014, I was told then HC meas. was too high, and good luck on passing your next smog, needs work lady. Where do I start to correct that? Right now cel is on, code read was p0440 evap issues. Been down this road before. Last year(p0455) repaired. Are the evap issues p0440 and p0455 tied into car emitting too high of HC ? I have read all the posts on where to look for this evap problem, great useful information on the last repair/fix thank you. Any ideas on HC emission troubles?
D.

 

Emission tests try to balance two measurements - HCs (indicative of unburnt fuel due to a rich burn) and NOs (Nitrous oxides indicate too much heat in combustion due to a lean burn). So, first problem is that many states will not pass emissions with a check engine light on, regardless of the measurements. Now, with that said, its possible your codes are related to the HCs. The root problem is either the air mixture is off (say due to a vacuum leak) or the spark is too cool (wires/plugs/rotor/coil). There are other possible causes (various sensors could be off) with the simplest cause being a loose gas cap or a bad gas cap seal. More likely its the J tube by the gas tank or a vacuum elbow under the intake manifold. My advise would be to get that code cleared first, then do a full tune up if it hasn't been done in recent memory - plugs, wires, cap, rotor at a minimum. I'd also look at the MAF sensor to see if the intake is clean and check for any other vacuum line or intake air leaks.

 

This is going to sound strange. The codes you are looking at are for evaporative emissions, which would be evaporating hydrocarbons. The codes have to be addressed as you know. The complaint you are getting from emissions testing is for high exhaust hydrocarbon emissions. They are not related.


The evaporative control system is very simple, and the 455 code is very specific, so you just need somebody that can effectively fix cars to jump on that and correct it.


Exhaust emissions are more of an issue, in my mind, because you don't have any error codes for that. You need the engine in good shape, a good catalyst and the air injection should be working. Every sensor on the engine itself needs to be reasonably accurate, and particularly you'd like the O2 sensors to be quite accurate. In my opinion they'd have some leverage on solving that problem. The computer hasn't set codes, so it thinks everything is reasonably accurate. Since it's a 97, it actually monitors O2 sensor health and the catalyst too, but it thinks it's okay.