Emissions Failure - 92 Sc400

[Silverback]

Hey there,

I have a 92 SC400 and it just failed the local emissions test.

Only work out of the ordinary is the BFI

I was told to replace the PCV valve, rotor, cap, plugs and she'd be ok, but she failed again.

Now they are saying replace the cats? Does this seem reasonable? Other suggestions?

Thanks in advance

[Silverback]

Hey there,

I have a 92 SC400 and it just failed the local emissions test.

Only work out of the ordinary is the BFI

I was told to replace the PCV valve, rotor, cap, plugs and she'd be ok, but she failed again.

Now they are saying replace the cats?  Does this seem reasonable?  Other suggestions?

Thanks in advance

←

I have decided to replace the Cats - anybody know the parts numbers? Are both driver/passenger sides the same? Estimated price?

Thanks

[DomLee]

Faulty O2 sensor?

[Silverback]

Faulty O2 sensor?

←

Wiser to do O2 sensor or cats?

How hard to replace and how much is an O2 snsor?

Thanks

[AppleJack]

I just passed my emissions flawlessly on a 92 sc400 with 230,000 km on it.

My tricks for emission tests,

1. new air filter

2. fresh oil change

3. full tank of sunoco 94 octane fuel

4. a good 20 minute run up and down the highway

But if your numbers are way off - then you may have sensors issues and depending on the test results, then a good dealer should be able to diagnose the cause of the failed test...

[Naslund]

Thanks for your tips, Jack!

I just bought 93 SC400 with 223km as well and need to do the emission test this week.

I will follow your tricks and hopefully it will pass.

Hey Jack, which garage do you normally use for your SC400 in Toronto?

Any recommendation?

Thanks a bunch!

[CLightning]

I just passed my emissions flawlessly on a 92 sc400 with 230,000 km on it.

My tricks for emission tests,

1.  new air filter

2.  fresh oil change

3.  full tank of sunoco 94 octane fuel

4.  a good 20 minute run up and down the highway

But if your numbers are way off - then you may have sensors issues and depending on the test results, then a good dealer should be able to diagnose the cause of the failed test...

←

I second that. Take your car for a long drive on the highway/freeway right before your smog test.

[SKperformance]

sunoco 94 higher octance will make your numbers worse for HC not better.

The only way to know what to fix is by what your readings of hc, nox and co are ,changing parts for the sake of it resolves nothing.

[JIBBBY]

I really don't think it is the cat as over time they get clogged and restrictive but still do their job, if you decide to change your cat which is a good idea anyway I would suggest you install a magnaflow catalytic converter, it flows much better, guiet as stock, and cheaper than the dealer item. I changed mine out 6 months ago and noticed a nice difference.