Emissions problem sanity check

[Spthomas]

I just took my 92 240SX to Nissan to have them try to work on the surging problem other seem to have (and they didn't have a clue either). But I wanted them to inspect it, and they had to take it to a competing dealer because they don't have the ability to do emissions testing on pre-OBDII systems. When they did, it failed the emissions test!

What they told me is they looked at the car to figure out why it failed, and (1) there is too much blowby, indicating they want to replace the engine. And (2) replacing the oxygen sensor might fix it long enough to get it inspected, since the sensor is oil fouled, but it might foul out again before I can get it inspected, due to the bad blowby. But I rarely need to add oil, maybe a quart every 1000 miles or more.

Does this make sense?

And if I can replace the oxygen sensor and get it inspected, is this a difficult repair?

=Steve=Not a Mechanic, more a Parts Installer

[blackbeauty240]

1 quart every 1000 is a lot dude i dont have too add any oil between oil changes. it might not be a big improvement but try using a thicker weight oil to take up the slack between the piston and the cylinder. this will raise your compression a little. as for the o2 sensor I dont think this is your problem although if its oil coated its bad. I think the burning oil is the reason you failed. replaceing the o2 sensor is easy IF its not seized up in the exaust manifold. its the thing bolted to the exaust manifold with one wire attached to it.

[yellow_jacket]

If yo upost your numbers it would be much easier to help you.

1 quart every 1000 miles alone won't cause it to fail. My Mazda burns 1 quart every 1500 miles and passes with flying colors. If your hydrocarbons are high, make sure everything is tuned up and running properly. If you really have a blowby problem, disconnect your pcv valve and breather before they test the car. I wouldn't drive it like this though. You can also change the oil right before it is tested.