Failed Calif Smog Test...need advice!!
 

1988 Porsche 911 just failed the California Smog test with the following numbers:

15mph:
HC (Max 121, Ave 31, Meas 186)
CO (Max 0.76, Ave 0.10, Meas 0.56)
NO (Max 807, Ave 237, Meas 1671)
25mph:
HC (Max 96, Ave 20, Meas 106)
CO (Max 0.65, Ave 0.09, Meas 0.34)
NO (Max 746, Ave 199, Meas 878)

The car has 95K miles and runs well. White smoke only comes out in the morning but it goes away after couple miles. The exhaust does smell a little all the time, but no smoke at all after the engine is warmed up.

Questions:
1. I found a bottle of $6.99 fuel system cleaner "CRC Guaranteed to Pass Emissions Test Formula" from Kragen, and it's supposed
to help "reduce CO, NO & emissions". Does anyone recommend that I try that out in order to pass the California smog test? Would that potentially damage the engine of the 911? Should I even give that a shot?

2. If I need to get someone to fix the car up so that the car can pass the smog test, does anyone know of any good mechanics in the San Francisco bay area that can help me fix up the car? Any idea on what needs to be fixed or how much it will run?

3. Any other suggestions/advice?

Thanks,
Andy

Move to rural Nevada.


No, just kidding.

With those NOx numbers (which are *very* high) your catalytic converter is dead almost for sure.

This is an example of where the smog test may actually help you and your car. Your cat is dead, and there is a good chance that it is clogged, too (I was at a shop yesterday looking at a melted down cat off a Carrera). Your car will probably run a lot better with a new cat.

I'd stick a new cat on it, and pre-test it again to see what the numbers are.

when was the last time you had a tune up? did you just get the car?

Did you get notified to take it to a smog test only station?
If you did, you are in luck. There's a program in California that will pay for up to $500 worth of repairs on your car (after you pay the first $100). If it is your cat (and I think it is) that $500 will come in real handy, especially if you need an O2 sensor too.
The program is good only if you are mandated to take your car to a test only station and it fails.

It was actually my brother's car but he moved out of the area and decided to give the car to me. The last tune up was probably from a while back, maybe 15k or 30k miles ago? :eek:

Any idea roughly how much it will cost to replace the Catalytic Converter? Would that help lower the HC as well?

Andy,
I just went through the same thing you did about six months ago with very similar numbers, but I knew mine was going to fail because I had a by-pass pipe instead of a cat conv(I bought the car out of state). I installed a used cat conv bought from another Pelicanite and passed with flying colors. I would check the classifieds of this website for a used OEM. I got mine for about $100. You don't even want to know what a brand new OEM cat costs. Just a word of caution, find out how many miles are on the cat and make sure to see pictures of the honeycomb-looking screen on one end to make sure it is not damaged or clogged. PM me if you have additional questions. Good luck

The way to prove its your cat is to drill a hole upstream of the cat and insert the emissions probe. Take readings before and after the cat. I agree the numbers will show your cat is dead. A new cat will reduce all three, including HC. You should expect less than .05%CO, and below 10ppm of HC. Many times the numbers will actually read 0.

I wish I had a brother who would give me a nice Carrera.

Seriously though, when you fail big time on NOx and fail HC too, you're in trouble. That's because when you lean it out to fix the HC, your NOx will go up.

Possibly your ignition timing has been advanced. That would increase your NOx output, and sometime HC, so do a basic tuneup first. Maybe try new plugs and check the ignition timing and mixture, otherwise you may need a new converter.

Regards,

Jerry Kroeger


Regards,

Jerry Kroeger

15mph:
HC (Max 121, Ave 31, Meas 186)
CO (Max 0.76, Ave 0.10, Meas 0.56)
NO (Max 807, Ave 237, Meas 1671)
25mph:
HC (Max 96, Ave 20, Meas 106)
CO (Max 0.65, Ave 0.09, Meas 0.34)
NO (Max 746, Ave 199, Meas 878)

easier yet is just pull the cat and look at it, an exhausted cat will be almost empty, a good cat is full of the cat "stuff"

where are you located?

jim

Where in the Bay Area are you, because there are quite a few good shops down there.

If you're cat is bad, you can purchase a used one anywhere from $100-300. As for a new one, I've seen aftermarket ones for around $500, but you can always just cut yours out, and weld in a new one. It doesn't meet the letter of the law, but it will pass.

Sounds like you need a tune up too.

no kidding on the good brother! check some of the local salvage yards for 911's. i think they will have some used ones.

In Northern California, check PartsHeaven (Hayward) or EASY (Emeryville). If PartsHeaven, ask for Spencer - tell him Steve sent you. Good guy (he just moved from EASY down to PartsHeaven).

Good luck and tell us how it works out.

Not sure about this but I believe state law prohibits the sale of used emissions equipment. I needed a cat from POS Mazda 323 my friends girlfriend had and we found one at the yard cut it off and then they would not sell it to us. :mad: Made my day!

yep, it is illegal to sell a used cat.
Not sure if that applies to individuals or just companies, but salvage yards won't even talk about it.

Even without a CAT, a 3.2 will run fairly clean. The NOx number is excessively
high. As mentioned above, an ignition timing which is too advanced, e.g. a bad
performance chip, will cause this. A bad plug, air leak, or wires can cause HC
problems.

You really need to go to a good Porsche repair shop and have some checking
done.

Good Luck
Loren
'88 3.2

My numbers were off the chart even more than that--even with a fairly new CAT. Of course you never do a smog check on these in hot weather or you're screwed.

What you can do is set the fuel quality switch to richen it up a bit. Mine is chipped as well, so it was running lean.

The fuel quality switch is on the DME unit beneath the seat. Do a search on Fuel quality switch and you'll find it. Consult Bentley as well. I also replaced my O2 sensor. Make the guy at Pep Boys or autozone go through and look for a 3 wire O2 sensor. A 1980s or 90s Euro car ought to do it. A good guy will find one for you. You'll have to splice it into the other wiring (2 whites and a black), but it'll only be 50 bucks instead of 200 for an original one with the connector.
Pour a couple of Octane boosters in there as well.
After all that your CO will barely pass you, but you'll get the NOX numbers down which is being caused by a very lean condition.
I think my engine is basically toast and that is why I had so much trouble.

Andy,
it is hard to tell what is wrong without more info about your car. I would start with checking your timing. Fuel injectors could be clogged and leaking some fuel. Getting a new CAT and testing very soon will let you pass the smog but I don't think you want to replace CAT every two year if something else is wrong. I would do a basic tuneup first before changing CAT or O2 sensor. It is good for your car performance anyways. To do a quick visual on CAT, take your muffler off, just three bolts 13mm socket, and look at the honeycomb in your CAT. If the honeycomb structure is clogged or melted in the center, you need a new CAT. Before next check, use very high octane fuel and take it to the shop on cold morning. I have limited access to dyno at local referee and my 88 motor will pass without CAT present. If you futher help give me a call.
925-292-5200
-steve

You can't just take a 1988 car into smog and expect it to pass without doing a tuneup for 30K miles. That's just silly.

Here's what you need to do:

- Check the car on the exhaust scope (baseline)
- Change plugs
- Change plug wires
- Change cap/rotor
- Change oil
- Adjust the valves
- Replace O2 Sensor
- Check the car on the exhaust scope (measure improvement)

If little improvement:
- Run compression check
- Run leakdown test
- Check for vacuum leaks
- Replace CAT

-Wayne

yea, what wayne said. plus i always include a new air cleaner. ( i never show myself at a smog station without brand new motor oil.)