Smog Help!
 

I've got an 86 944 that is having a hard time passing smog. Im located in California. I had the car tested and it was high on the HC and CO at both 15 and 25 mph. The NO was fine. When I started inspecting the car, I found that the timing belt teeth were broken off so the timing had slipped quite a bit. I ended up replacing the timing belts and setting the timing back to normal. The car has new spark plugs, a new o2 sensor, and a new cat. I took it back to get smogged and I had the exact same results (high on HC/CO and low on NO). The gas in the tank was a bit old. What do you guys suggest I do?

sounds like it is running rich. bad O2 sensor. change the air filter. get new gas in it.

Check my website it may help you. www.budsave.myffi.biz
I have use it on all my 944 for over a year now. It give me better gas mileage/ more power/ cleaner air from tail pipe and I am using regular gas instead off Super.
When I have to total my 86 944 and keep the car for parts car, I take the exhaust out to be install on my 83 944 and toke the O2 sensor out. To my surprise it was no carbon built up on it.
Good Luck with the smog test

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Bud
87 930 Black
86 951 Black daily driver
87 944S White Son daily driver
86 944 N/A Red totaled (part car)
83 944 N/A White Auto wife car
83 944 N/A Black

Wow, how did you manage that! If the timing belt on a 944 slips more than 1 tooth while it is running, it will bend the valves and will not run. You sure it wasn't the balance shaft belt that slipped?

Sorry to burst your bubble but my car passed the CA Smog check today.

I always use BG44k before a smog check. It is the best fuel treatment I have ever used. It's expensive at $24 for a can, but within 5 miles, you will feel your car running better.

That being said, looking at my test results, my HC was still fairly high at 45 & 19, my CO% was .03 & .02, my NO was .0026 & .0014 for the 15 & 25 mph tests. I'm thinking that these cars may run high HC as I have new oxygen sensor, and air filter. My plugs have about 10k on them.

Definately, try the BG44k, I've been sold on this stuff ever since I first tried it a few years ago.

Vern

^ +1 on the BG44K. It does really make a difference. It is about the strongest fuel system cleaner available. Not only is it expensive, but you have to buy it from a shop or gas station that distrubutes it. You won't find it on the shelf at a auto parts store. But it's well worth it if you've never used it.

I get mine at CarQuest. It's the only regular parts store in town that sells it.

Another thing I am experiencing is that the rpm is surging at idle. It will idle about 900 for 10 seconds then drops down for a couple. It then picks back up to 900 and drops again. What could be causing this? A vacuum leak? Will this affect smog?

My idle surges just like you described. It still passed smog so I don't think the surge affects pollutants. I beleive the surge is caused by a dirty idle control solonoid that is not reacting fast enough to engien changes. It could also be caused by a vacuum leak.

On my car, I have changed every single vacuum line, including the hard plastic lines. The only line I have left to change is the funky one that goes to the idle control valve. Even with the lines that I have changed, my idle still surges. I'm planning on removing the idle control valve and cleaning with carb cleaner - but, you really need to remove the intake manifold to do this. Which is why I haven't done it yet.

Vern