...I posted this in the 1992-1999 topic section, but since I'm pressed for time, I posted it in this section too - I hope nobody minds...

Has any of your Bonnies failed a smog test, and if so, what was the cause/fix?

I'm asking because my '93 SSEi (140,000 miles) is due for a smog test soon (here in so. Ca.) and I just looked at the test results from 2 years ago and noticed that although it passed last time, the HC measurement only passed by 3 PPM on the 15MPH test. At 15 MPH it measured 114 PPM (max allowed is 117) and at 25 MPH it measured 48 PPM (max allowed is 67). Also, at 15 MPH the CO measured .31% (max allowed is .48%) and at 25 MPH it measured .12% (max allowed is .45%).

The catalytic converter was replaced last summer because it rattled when accelerating, and I replaced the O2 sensor with a new Bosch sensor a couple of months ago because the fuel economy was 12 MPG once, and it was a big drop from the usual 16-18 MPG. It seems to be back to getting 16-18 MPG again.

The engine seems to run well, just as it has since I bought it in 1999.
There aren't any error codes.
There'* roughly 2,000 miles on the oil, but I'm going to change it before the test anyway.

What else can/should I do to help ensure that it passes the test?

Thanks.

Bill, the only thing I can think of is that Bosch O2 sensor. We've had several cases of poor performance and premature failures with them. I know CA didn't used to charge full price for a retest, but they do charge (I used to live there.....grew up in CA) so you may consider offing the Bosch for an AC Delco sensor beforehand just in case.

Other than that, it sounds like you're in pretty good shape.

I ordered a couple of Delco O2 sensors yesterday, but they won't arrive in time for the smog test deadline.

I think I'll leave the Bosch unit in there for the test - after all, it says right on the box that it reduces emissions and increases fuel economy

I just hope that there'* nothing wrong with the engine - rings, valve seals, etc. I've never seen it blow smoke out the tailpipe, and it only drinks a normal amount of oil, so I'm hoping for the best.

I called a couple of smog test shops this morning. At the 1st shop (test and repair station) the guy didn't seem to know much, but at the 2nd shop (test-only station) the guy seemed to know a lot, and according to him the new catalytic converters are much much better than they used to be, so he suspects that a new cat should make it pass within a wide margin.

Sounds about right to me. I think you're gonna be fine. The only other thing (remote chance) would be a leaking or loose vacuum fitting going to your purge canister.

Well, I took it in on Friday, and it passed with flying colors. The measured values were all far below the allowed maximums, so it'* clear that the new catalytic converter and O2 sensor did the trick. I changed the oil and filter first, too, just for good measure.

The "hot" twist is that it took the mechanics longer than usual to test the car, and when I asked why afterwards, one mechanic told me that it was because the engine came close to overheating during the extended idling warm-up period. I asked him to show me where it read on the temp gage at that time, and I expected him to point somewhere near the 240 degree mark, but instead he pointed at the 220-degree mark and said these GM cars shouldn't normally get hotter than 200 degrees. I told him that 195-220 is considered normal for these supercharged cars, but he didn't believe me...