Red1

You have vacuum leaks. From the looks of your NOx numbers, more than one. Get a vacuum tester and check every single thing under the hood with a vacuum hose on it.

I have SO BTDT. Mine has failed nine emissions tests in the past six years. Always due to a vacuum leak I didn't know I had. Guru chips are not your problem. I know that from firsthand experience as well.

If you assure it's air-tight but still get funky numbers, make sure the TPS is adjusted correctly. That's another one that'll bite you in the *** until you learn to check it.

Tx951Dude

Welcome to the club, lol. My car failed again last November when it had passed just fine a year earlier. The only change between tests was when a lady rear ended me at a major intersection at night and then decided to drive away instead of pulling into the nearest parking lot. Maybe she was freaked out that she rear ended a Porsche and would have to pay a fortune for repairs. I've been driving my car only at night for the past year so the PoPo can't "see" my lack of current sticker.

All I can say is it seems that Texas has some sort of racket with the car repair facilities and are trying to get the older cars off the road, if possible. Good luck to you sir.

Droops83

You need a cat to pass for NoX emissions, no way around it. If your engine is tuned right and running well, you can actually sneak by w/out a cat on a turbo car if the emissions tests are done only in neutral (idle and 2500 RPM) like they do here in Santa Barbara for "Basic" smog tests, but if you're under load on a dyno (like in the more populated areas that have "Enhanced" tests in CA or like they do in TX) you'll fail on NoX every time no matter how well your car is running if you don't have a cat.

mtnman82

+1 on getting a cat for the test. I've had Guru chips (w/cat, stock inj, AFM) in the past 3 times I've gone thru smog and passed OK. I've kept the Guru chips/stock inj in case I need to go back to pass smog...

brad-cam

I just had my '87 951 tested in CA today and it passed pretty much with flying colors. I've ensured no vacuum leaks, a pretty new SFR cat, AFM, stock
injectors and Guru chips.

Here were my results for comparison. My car's results are the "MEAS" numbers:

15 mph:
RPM: 2515
%CO2: 14.3
%O2: 0.2
HC (PPM): MAX: 116, AVE: 31, MEAS: 59
CO (%): MAX: 0.74, AVE:0.10, MEAS: 0.04
NO (PPM): MAX: 791, AVE: 237, MEAS: 239

25 mph:
RPM: 2415
%CO2: 14.2
%O2: 0.1
HC (PPM): MAX: 91, AVE: 20, MEAS: 28
CO (%): MAX: 0.62, AVE:0.09, MEAS: 0.00
NO (PPM): MAX: 730, AVE: 199, MEAS: 267

KuHL 951

Hey Brad...where you been?

Fluidplay

TroyN - interesting find, just took mine in this afternoon and only failed the NO at 15mph (max=1125) mine read 1263. Everything else was well within the limits. That being said, if I interpret what you discovered...that if I richen things up a bit in that range my NO reading at that speed will go down? Am I understanding this correct?

PEvans

If you are in CA and you have to pass NOx on a dyno you'll need a working cat, and the 20+ y/o original probably isn't good enough any more. Fluidplay might get lucky one more time, but I sure wouldn't bet on it. Those of you in states that only test for HC and CO idling, that is a whole different world.

The good news is with a replacement cat you get numbers like Brad's. A replacement cat may only last 4-5 years though.

brad-cam

Good to be back Steve - been busy with my other cars and work, but smog time brought out the 951 again

Smog testing always makes me mad. My 1000 miles a year are not doing too much to the environment !

brad-cam

When my smog guy heard that I had a new cat, he said he would check it to make sure it was "CA-certified", whatever that means. I figured, "great, time to fail on a technicality", but he said it had a "CA" stamped on the side of it. If you replace your cat, you might keep this in mind. I think it is a Magnaflow cat. Interestingly, he also said to me "I have no idea what that shiny valve is in your exhaust system" but he didn't seem to care. He was referring to my Tial wastegate....

Trucho-951

I may have "accidentally" sprayed my shiny Tial valve with flat black paint the last time I had the 951 smog tested.

PEvans

I have been told by a tester that my wastegate was an illegal bypass of the cat, and he was ready to report the car. It was actually good that it was a first test and it had failed. I was able to get it tested again somewhere else (passed with a new cat).

I have heard that in CA the cat has to be a "direct replacement," not a universal, but it sounds from Brad's story like that is not always the case.

ilikemy944

Wow.
I am super glad we don't have rules that strict over here. In fact, I don't even have to have my car tested at all where it is registered.

brad-cam

It seems the laws around replacing cats in CA with aftermarket units have recently clamped down further.

See here: http://www.arb.ca.gov/msprog/aftermk...ftermktcat.htm

There is a list of exempted manufacturers/models there and Magnaflow is on this list. I've noticed that some of their parts have "CA" appended to the part number which is what I have on both my 951 and 911SC. The 911 has also routinely passed smog with really low NOx numbers.

KuHL 951

The reason that California clamped down on aftermarkets cats was because the $99 cat specials sold at many places were good for about 3 months and then shot like on my BMW. They would often just weld any available model on the car and call it good. I've bought 2 new MagnaFlows this year and can confirm that they are both CA certified, vehicle specific, and designed to last much longer. If I have to have smog testing I'd rather have a component I can use more than 1 time.