79 failed emissions due to CO being too high

[qposner]

Well, I took my 79 to the Oregon DEQ and failed (just moved to OR from WA where emissions were not required on a 79 car). CO was 2.375 on idle. They told me it should be 1 at the highest. Everything else appeared to pass. Any suggestions before I take it to a shop and spend way too much $$? Cold start valve (since it appears it is a too rich idle)?

Thanks!
Quinn

[vf31rhill]

First of all, you did not hear this from me. This is a little sophmoric, but when the tech puts the probe up the tail pipe, it is like an eye looking for light at the end of a tunnel. The probe is looking at a stream of exhaust gases with small molecules making up the stream. If it "sees" large hydrocarbon molecules blocking its view , it fails the the test. So anything you can do to reduce incompletely combusted hydrocarbon molecules is in your favor.

Things you can do to help the situation.
STP or similiar products in the oil to help seal worn piston rings and reduce oil passing by the rings and being combusted in the firing chambers is in your favor.

Removing the air filter will inject a little more air into the combustion champers. Don't leave it off forever, just for the trip thorugh the inspection station. Some cars will not run at all without an air filter, so you may have to play around with a sacrifice filter, opening a large section in the middle but still leaving some of the filter in place.

Finally, the coup de gras. For some reason I fail to understand, retarding the timeing will cause you a tremendous power loss, but will give you a cleaner tail pipe. Your timing is currently at so many degrees before top dead center (TDC). If you retard the timing, you move it farther toward TDC, or reduce the number of degrees before TDC that the plugs are firing. As you move it toward TDC, the power will fall off , eventually becoming so weak the car will hardly craw it's weary *** to the inspection station. But you will get a much lower CO reading during the test. Best proceedure is to experiment around until you find the degree setting at which the car will barely move under it's own power. Drive to the inspection station, stop a few blocks away, and set the timing to the "weary craw" setting. Go through the inspection, and afterwards stop and re set the timing for normal driving. Don't know why this works, but it does. Again, you did not hear this from me.
Robert

[Andrew]

High CO means excessive richness.

On a Spica car, there is no cold-start valve as such. There is an enrichening cold-start solenoid, which is activated only as long as the key is in the Start position, and the thermostatic actuator, which sets the mixture based on engine (water temp) Rich when cold, lean as it warms up.

You should do a full ignition and Spica tune-up including checking whether your actuator is functioning right. The car should be good and hot (20 minutes of hard driving right before the test, with a working thermostat so the engine is at the right temp) and tested immediately while hot. So the actuator's cold setting shouldn't even come into play in the test.

There is a lot of god info on the BB about doing a Spica tuneup. If you're not capable of it, take it to a shop or Alfa club friend who is.

Besides your actuator, are your cat and air pump working?

Andrew

[sunsprit]

If all the "smog" equipment is on this car and working, then it should easily pass the tailpipe test if it is tested when completely and thoroughly warmed up. It's essential that the tailpipe test be performed on a warmed up car and not one that's been sitting around for awhile waiting to be tested.

Also essential is that the correct 180F dual plate thermostat be installed and working properly. I've seen single plate t-stats installed which give a lower temperature to the water flow by the sensor for the SPICA injection pump, which will then run a richer mixture in response to the low coolant temp. Also, be sure that you've got a functioning in-tank delivery fuel pump and proper fuel pressure at the SPICA injection pump from the main fuel pump. A working fuel pressure light on the dash is a great help, you should see it cycle out on turning the ignition on every time.

The instructions posted by the Oregon Alfa Owner's Club for a SPICA tune up are very good, and easy to follow. The SPICA adjustments are something you'll have to do at the end of the sequence with some road testing and driving cycles to be sure they're right.

Even with a "worn" motor, these cars should adjust into compliance for the CO.

I've seen them without a working air pump or catalytic converter and still get less than 1% CO out the tailpipe and minimal hydrocarbons. Of course, that's with stock compression ratio and cams ... alterations here can radically affect street idle CO% readings, making the air pump and cat converter all the more critical.

[qposner]

Thanks, everyone. I just got back from a weekend at the coast so I am just now reviewing these replies. I have NO idea if the emission equipment is working correctly or not. While the car has been in my family since new, it needs some work. I just want to get through DEQ and worry about a SPICA tune-up later. When I went through, I drove approx 5 miles of surface streets and the water was at 180. I was the 2nd car in line and sat for about 5 min with the engine off but it was still 180 on the gague. Do you think it would be better if I ran it hard for 20 minutes (windy backroads) and then hit DEQ and leave the engine running while in line? I can yank the air filter, etc as well.

Thanks again!

[sunsprit]

Shutting the car off for 5 minutes after such a modest drive to the test station would be long enough for the motor to cool down enough to allow the fuel enrichment of the SPICA pump functions to activate.

Unfortunately, you really must determine if the emissions equipment is installed and, if so, functional, before any other tuning or adjustments are performed. At the bare minimum, if you want to "skip to the chase" of adjusting the SPICA pump leaner, you'd be well served to read the full tuning instructions mentioned above and then put the SPICA pump adjustments in perspective.

Absent a CO tailpipe tester of your own, you're simply guessing when you make the adjustments. The tuning sequence will guide you to a probable best outcome, but that's not the same as knowing what your car is putting out before heading down for repeated tests at the DEQ. Better, I think, to go through the tuning sequence and optimize your car and chances for a successful outcome before heading down to a test.

I'd keep the car idling at the test station after a hard run up. While the SPICA injection senses water temp, the real benchmark of a totally warmed up motor is that the oil is up to it's normal operating temperature. We don't have oil temp gauges in these cars, so you must infer full temp from hard running and normal water temp for some period of time.

[qposner]

Thanks, Sun. Point well taken. The car really does needs to be worked on. When hot, oil pressure drops to around 10-15 lbs at idle which is lower than I would like to see. Fortunately, DEQ is free until you pass and takes 20 minutes out of my day as the station is 10 minutes away. I will go through the injection system. How would I go about determining if the emission equipment functions? I assume it does as hydrocarbons, etc where fine. It was just that CO was a bit high.

[Andrew]

As I said above, high CO usually means too rich. I'd bet your thermostatic actuator is not functioning properly, and not leaning out the car enough when it's hot. Get and read the Spica setup info here, or have it done if it's beyond your abilities. An essentially OK engine, decent pump, and good cat should pass OK.

Have you checked your ignition and compression, to make sure they're OK? An engine that has fundamental problems like low compression will not necessarily pass. Low oil pressure at idle is not usually a problem, as long as it's OK at higher rpm (like over 55 at running speeds).

Andrew

[qposner]

Quote:

Originally Posted by Andrew As I said above, high CO usually means too rich. I'd bet your thermostatic actuator is not functioning properly, and not leaning out the car enough when it's hot. Get and read the Spica setup info here, or have it done if it's beyond your abilities. An essentially OK engine, decent pump, and good cat should pass OK. Have you checked your ignition and compression, to make sure they're OK? An engine that has fundamental problems like low compression will not necessarily pass. Low oil pressure at idle is not usually a problem, as long as it's OK at higher rpm (like over 55 at running speeds). Andrew

[Andrew]

That's a low reading when hot, but it might be the gauge or sending unit, not an actual problem. Either way, unless you have seriously knocking rod bearings or something like that, low oil pressure in itself is not a smog-check problem.

Andrew