I recently moved to Las Vegas. A smog test is required, even for classic car plates. The test consisted of two minutes at 2500 rpm, idle, 1000 rpm, idle, 2500 rpm, idle.

The car passed the 2500 rpm CO test of 2.50 with a 2.16. However, it failed the idle test with a 3.44. The tech stated it was idling too rich.

The car is a '76 912E with the 2.0. I installed a new K&N filter to maximize air flow. What else can I do to lower the idle CO reading?

There is a provision for a waiver, after $450 in repairs at an approved shop. I would like to put the money elsewhere.

Help?

Oh yeah, my 914s got sold as a pair to a real enthusiast in Memphis. He will do them proud.

10% by volume alcohol in the tank - just enough gas in tank for the test and the drive there. Everclear, available at your local liquor store should work.

Check fuel pressure

etc, etc, etc

What are the other numbers? If HC and CO are both high, then the tech was right, and you're running rich. High HC would be anything above 150 or so. The alcohol trick may work, but if you get your car running properly, you'll get better gas mileage all the time, not just get it through the test. If you haven't done a tune up recently, have one done now.

The numbers read:

HC ppm CO CO2 02
limit reading limit reading reading reading

2500 500 96 2.50 2.16 15.70 0.2
idle 500 211 2.50 3.44 12.30 6.3


everything is marked "Pass" except for the idle CO.

What happened to the format? That is not how I typed it.

Maybe this will look better:

HC ppm:
2500 limit is 500, reading is 96
idle limit is 500, reading is 211

CO 2500 limit is 2.50, reading is 2.16
idle limit is 2.50, reading is 3.44

CO2 2500 reading is 15.70, idle is 12.30

02 2500 reading is 0.2, idle is 6.3

Oh yeah, the gas here in Las Vegas is oxygenated. Could the gas in the tank from Missouri be causing this?

Regardless of the real problem, you live where it's dusty, and you installed a K&N? Bad move. Less filter area, bigger pores, degraded air flow when it's loaded up even a little bit, it allows that oil to enter the intake air stream, as well as a LOT more dirt .................. The Cap'n

Now, the CO. Open the air bleed screw in the air box. That's the idle CO adjustment. Doesn't really affect the high RPM numbers, but it can make a HUGE difference in the idle readings. Also The Cap'n

Now there's some info that is useable!!!! Thanks.

Oh, I realize the K&N is not optimum, but it is to get the car through the test. The panel filter I removed was pretty funky, but it seems to be very effective.

I went back to the test station this afternoon and mentioned to the tech that I had noticed that the gas in Vegas is oxygenated, and the 912 still had St Louis gas in it. He recommended fresh gas, and also an oil change if it had not been done very recently, which it has not.

Now I have my weekend chores.

To almost answer my own question:

Today I spent some time at Barnes & Nobel. There was a softcover book by Motorbooks International, "Bosch Electronic Fuel Injection" or something close that had sections on each type, including the 912E pertinent K Jetronic. Very informative, an easy read.

I need the 3mm long key and an exhaust analyzer.

Gonna take it to a shop.

Thanks for the responses.