944 Failed Smog

[Ted Myrus]

Trevor's 944 failed its smog test today.

2,126 RPM----------- HC (PPM) 223; NO (PPM) 2613
2,300 RPM----------- HC (PPM) 177; CO (%) 0.86; NO (PPM) 2244

Awarded a gross polluter result

Starts, idles, and runs OK (Do 944's ever run good?)

Looks to be too rich. Do we have a bad oxgen sensor telling the computer to send more fuel? A bad temperature sensor?
Don't hear or see any vacuum leaks. Is the catalytic convertor past its prime? Is the DME asleep?

Can't give it to Father Joe, I just bought new tires.

Is there an obvious fix? Anyone have some good ideas? A magic fix, some inexpensive parts?

Spec Racers must have a pile of unwanted smog parts.

Thanks,

Ted

[Jad]

Ted,

I am not an expert at diagnostics from that data, but most 944's do need new cats and O2 sensors. Find a working cat to bolt on for the test, and buy a new O2 and I bet you pass, because unlike old 911's and 356's, old 944's should run very well if things are working.

good luck!

[Tim Comeau]

Geez, I dunno.........too bad there isn't a 944 expert in town with factory cats, 02 sensors and a ton of test data......
All it takes is someone to tweek the air flow meter a couple turns to try to get more power or more fuel economy. Could just be a cracked header.
I haven't met a 944 or 924S that I couldn't get to pass smog legally. References avail.
Call me. I'm ready to serve you. We'll keep that 944 where it belongs.....on the road supplying tons of fun!

[Sparks]

+1 on Tim. He has always done me right.

[David Polk]

I know this is a older post,but, Same issue's went to tim's shop, bolted on a known good cat,
Passed smog with great numbers, new o2 sensor a few years back, and a minor tweak of the air flow meter door and it passed with great numbers.
there is also a article on I believe clarks garage on testing your O2 sensor with a multimeter to see if it is functioning,
May have to Google for that one as I can't remember where I found it.
so, test the 02 sensor or replace,(I used the cheaper splice in one), and let tim loan you a known good cat,
then, if you pass, replace your cat, and you will be good for a while, Tim will also take a look at your car while you are there and let you know if there are any other issues that need dealt with,
I don't know anyone more passionate about these cars then Tim, My car runs extremely well.
Also, Tim did a valve job and new Belts and other Maintenance on my almost 300,000 mile 944,
Well tuned 944's run very well.