s329

My new to me 87 3.2 just failed the CA smog test with a high NOx reading of over 1000. Everything else was okay. I was going to need a good mechanic anyway but now definitely need someone so I can pass the smog test. The car has 85k miles on it and it is stock. A search on this issue basically starts with looking at the O2 sensor Or cats so I'll start there. Can anyone recommend me a good trustworthy Indy around the palos Verdes, Torrence, LA area? Thanks!

SPDADCT

Use 91 Octane good quality gas, add a good fuel system cleaner additive and drive for 20+ Miles of Freeway to burn off everything. Replacing the O2 sensor is a good idea.

Then you can take it back for a pre-test to the same place and see it passes before doing the actual test (No results sent to DMV on pre-test). If you need further help, let me know.

rusnak

Make sure that there is no performance chip in the DME, and that the brown wire is connected next to the DME harness.

A sensible starting point is to simply tune up the motor, then check the air fuel ratio and fuel pressure. If within spec, then you might at that point change out the O2 sensor. Borrow a known good cat if you're running a bad O2 sensor (or running very rich), which might have contributed to an early demise of your cat.

There are a lot of good wrenches in LA, or in OC. You know who might be good is Otto's in Venice.

s329

Thanks for the replies so far. I get some initial smoke upon startup but after that it subsides. Fresh tank of 91 octane gas and drove her about 30 mins prior to the inspection. The high NOx number still has me puzzled as some say it's an indication of running rich and some say lean. Lastly is borrowing cats something fairly common for situation likes this? I'm mostly used to 997s and that car being in NY, this whole CA smog thing is driving me nuts!

rusnak

Borrowing a cat is one way of finding out if your old one is bad. That's why you borrow one for the test....

Droops83

Go to Callas Rennsport in Torrance, Tony and his guys are as knowledgeable as they come about these cars. They should be able to zero in on the problem relatively quickly without you wasting a bunch of time and money trying everything first.

1986 Targa

Have a chat with Robert @ Dutch Treat Porsche:

http://www.pcarshops.com/california/dutch-treat-porsche

Peter Zimmermann

If you want to go down to Long Beach, Marc @ Red Line is at 562-901-2900.

s329

Thanks a lot for all the helpful replies guys. I went down to chat with Tony at callas rennsport and it looks like the car isn't running a standard oem cat. We're going to take care of that first and see if that suffices. It was clear that he and his team had Porsche blood running through their veins and I felt that they were as knowledgable as any Indy I have spoken to on the east coast. I will keep you posted on my progress!

Lorenfb

"it looks like the car isn't running a standard oem cat"

It 'looks' like, really? Beware that a CAT replacement can be very costly especially
when that's NOT the problem. Many shops like to 'load' the customer with
parts in an attempt to 'shotgun' a problem solution. Some good preliminary
checking has been mentioned in this thread that should be done before 'opening'
one's wallet.

Bottom line: One ALWAYS needs to properly analyze the problem before
replacing costly parts!

rusnak

Some context might be helpful here.

A factory Porsche cat will cost around $2K, maybe more.
A DEC 49 state legal cat will be around $700, and a 50 state legal cat maybe $800 or so.
A scratch built cat that will still get you to pass but not look pretty would be around $250 installed.
A borrowed cat will cost you a few beers or so, maybe lunch.

An O2 sensor costs whatever it costs depending on your donor wire condition you might go with a universal 3-wire, although there are good arguments for going with the factory 3 wire O2 sensor. Either way, they are consumable parts, and need to be replaced about every 50K miles or so.

A tuneup is probably in order anyway, and you did say the car failed smog.

Whatever you do, knowledge is power. Wish you the best.

Peter Zimmermann

Yep. Had a recent similar problem myself. Did all the preliminaries first...

tone40

Tony

Droops83

It sounds like they did a quick visual inspection and saw an aftermarket cat, which could potentially be a problem. I would imagine that when he brings it in for a proper full inspection they will sniff the exhaust with a 5 gas analyzer and go through all of the requisite preliminaries before condemning the cat.

The reason that I suggested to go to a good shop is that they have both experience and a gas analyzer, so they can quickly zero in on the problem without guesswork and throwing parts at it and trail and error at the smog station.

10 GT3

Actually, you want to do the opposite. The higher the octane, the higher the emissions.

Run the tank close to empty. Fill up with a half tank of regular unleaded and add a bottle of RXP. Make sure it is well mixed and when you take it in for inspection, make sure the car is completely warmed up. You should be able to squeak by.

I haven't worried about this type of issue for a long time. In Texas, once you hit 20 years old there is no longer an emissions test, just safety. My 79' SC has not had a cat on it in the last 10 years I've owned it and will never see one ever again.