911-3.2

We had to bring our 86 911 in for emissions testing today and it failed. According to the test the CO emissions level was 3 times too high. This is under Connecticut's new emissions setup. I was wondering if anyone else has had issues with getting their cars to pass and what can be done about it. We're having it looked at on Monday by the guy who did the PPI for us. Any input would be greatly appreciated.

James

Peter Zimmermann

James: I assume the car runs well, just rich. If that's the case the culprit is usually the air flow meter. Good luck with the problem...
Pete

911-3.2

Thanks Pete, it does run well. I forgot to mention it has 83k miles. The valves have been adjusted about 3,000 miles ago.. I have had someone follow me and notice that it smokes a little bit at lower speeds when changing gears, but from what I read that could be the valve guides starting to wear. I hope it's just the air flow meter like you said.

James

Lorenfb

Check out this web site ( www.systemsc.com/diagnostic.htm ) on the Poor Running
section for some troubleshooting info for your problem.

Gost

Do you have a performance chip installed. I understand that these can effect the emmisions on those years Carrera. If so replace it with the original chip if it's still available. Although having a reading 3x's too high sounds more than a chip would do. I have an 85 Carrera and reside in New York and am understanding that cars 20yrs and older are exempt from emmissions at that age. Perhaps that does not apply in Conn. hence not of any help but if it is the law then your 86 may have rolled off the line in 85 sometime before 4/13/85 and meet that requirement. If that won't work then at least next year you could throw in a new exhaust, chip etc and twiddle your nose at the emmissions test.
Worth a look into.

mobilewrks

what were the readings for everything else. how many ppm on your hydro carbons

911-3.2

Thanks for the links and responses. The car has a stock chip. I've searched around some more and it is looking like the air flow meter is the culprit. I will update after it's been looked at again.

James

CrossT

I just went thru this with my 86 and passed the second time around. I was WAY over the allowable the first time. The car was running great and the failing result was unexpected.

What I did was install a new Catalytic Converter since mine was nearly to the 180K mark [you can get them new for $280 shipped - installed at home in an hour], and I adjusted the AFM across-the-board mix internally [i.e., by the spring]. The AFM external hex adjustment below to the front left only affects the mix at idle. Tightening the tension on the spring leans out across the board and vice versa. I tightened by three teeth, but since passing I have backed off a bit since the car was so far under max allowable that I was afraid I was running too lean [heat, valves].

I'm not sure I'd suggest this approach, and if you don't want to take some things apart and mess with it then a shop is the way to go.

todd
86 coupe

911-3.2

Here's the update as promised. We brought the car in and they found it to be running really rich. The tech leaned it out and this time the CO output was 0. The first time it was 1.38 which is almost three times the max allowable.

It's going back soon for tires so I am going to mention what the reading was at the emissions station just to be safe. The tech had adjusted it to be well under .50 but I was surprised to see it come out as 0 at the emissions station. I'm wondering if the discrepancy has to do with the two different machines. Since the air flow meter adjustment I've noticed that the idle is lower and the car is much smoother at lower speeds than before.

Thanks again for your help everyone.

James

eldiosyeldiablo

CrossT, where did you get your Cat. from?

Peter Zimmermann

James: Your tech set the CO% before the cat, the smog shop tested after the cat, which is a true reading of what's going into the air we breathe, not a tune-up spec. Cars like yours run extremely clean out the pipe when everything is set right. Enjoy!
Pete

911-3.2

Sweet, that explains the difference. I'll definitely be adding your book to my library. Thanks again.

James

glenncof

My 1985 Porsche 911 has 159K miles and I just completed my first California dynometer smog test and passed the 20* second test at both 15 & 25 MPH *(if fails at 20 sec. they can repeat test with two minutes each speed). It did fail the gas cap pressure test and the tech gave me a new one for $10. The tech also said changing old oil helps.

I have owned the car since 17K miles and have almost all smog test reconds.

My CO was getting up to 0.92% (fail at 1.2) at 144K miles two years ago and I was expected to fail the new testing. It has never failed smog.

So I replaced O2 sensor for the first time before the test. They only have 100K miles life expectancy. See my project posting on this board for details.

I read your tech adjusted fuel mixture. That seems odd since it is fuel injection and is set electronically (pulses) by the engine control unit.