Smog failure

Spiderferg · Post by **Spiderferg** » Sat Mar 18, 2006 5:08 pm

I am having trouble getting my 78 Spider to pass smog testing. I have replaced the air pump and still no luck. A shop suggested slapping on a cat converter? Any help out there?

Thanks- bob[/b]

So Cal Mark · Post by **So Cal Mark** » Sat Mar 18, 2006 8:10 pm

need more info; what type of test-2 speed idle or loaded mode. And what were your numbers and what are the limits?

Spiderferg · Post by **Spiderferg** » Sat Mar 18, 2006 10:29 pm

thanks for your response, it is failing in the CO Carbon Monoxide "loaded" test. The reading is 3.82 and the limit is 1.65.

Danno · Post by **Danno** » Sun Mar 19, 2006 12:28 am

Here are a few things you can do for CO:
Fresh intake
New plugs (properly gapped of course)
make sure your timing is A+
New/add a Catalytic Converter

I'm not an expert on this though, hopefully some others have some suggestions for you.

So Cal Mark · Post by **So Cal Mark** » Sun Mar 19, 2006 12:33 am

That's a pretty tight standard for the Spider to meet, pretty similar to the Calif limit. One problem is that these cars were never designed to run that lean. So, even if everything is working, I usually have to rejet the carbs to pass the test.
But, the first thing is to make sure the air injection is working properly. It's common for the air injection manifold to get plugged with carbon. One way to check it is to remove the hose and check valve and blow compressed air into the ai manifold. There shouldn't be any resistance at all. If there is resistance, remove the ai manifold and try cleaning it.
If you have to rejet the carb, be careful not to go too lean or the HC and Nox will rise.
Do you have to pass a loaded test at 2 speeds? Calif does a loaded test at 15mph and 25 mph.

Bob · Post by **Bob** » Sun Mar 19, 2006 1:19 pm

Strange coincidence? How many Bob's with 78 Spiders live in Gilbert AZ? At least two! Present company included.

So Cal Mark · Post by **So Cal Mark** » Sun Mar 19, 2006 1:25 pm

how exclusive is that club?

Bob · Post by **Bob** » Sun Mar 19, 2006 9:41 pm

The club is smaller than you think. I met up with the other Bob this afternoon. He drove his newly acquired 78 over to compare things. Come to find that we have known each other since 1992 since we both work for the same company.

Both cars are red.

So Cal Mark · Post by **So Cal Mark** » Sun Mar 19, 2006 10:09 pm

it's like bizarro world! Maybe you could take his car and get it smogged in place of yours

Bob · Post by **Bob** » Sun Mar 19, 2006 11:16 pm

I had the same problem a year ago at the same inspection station that Bobs been going to- I failed the loaded CO by a lot. 6.45 (1.65 max to pass). Also failed the HC at 291 (250 max allowed). Before the retest I tried the typical tricks, retard the timing and add 1 part denatured alcohol the four parts gasoline in the tank. Even still, I think the biggest problem was that the inspector performed the load test in second gear. I'm not sure what speed the test 'rolls' at but the RPM's were screaming. On the retest, I sat in the passenger seat (again) and requested the inspector put it in third gear. Initally he resisted but when I pushed him on this point, he complied and ran the load test in third gear. RPM's were a lot lower and the results were significant. CO went from 6.45 to .25 and HC went from 291 to 62. Idle results were essentially unchanged. I'm keeping my fingers cross that the other Bob has the same results!

So Cal Mark · Post by **So Cal Mark** » Mon Mar 20, 2006 12:53 am

there usually is an rpm range along with the mph, I know here in Cali, the 15mph test is in 2nd and the 25mph test is in 3rd. It's also important to have the catalyst hot, but that won't cut the CO that much.

Bob · Post by **Bob** » Mon Mar 20, 2006 4:19 am

Both of our 78's are non-catalyst. I'm sure neither was originally sold in CA. They only perform a single load test here in Phoenix and I'm guessing that it is the 25 MPH. Because of the model year, it has to be tested every year which kind of bites since newer cars only need to be tested every other year. Cars less than 5 years old don't need to be tested at all, but the state still collects an emissions inspection fee on the registration. Great system...

Now, concidering that I was not conducting a controlled experiment were only one variable is changed at at time, which change do you think contributed the most to the improvement; retarding the timing, alcohol in fuel or lower RPM?

So Cal Mark · Post by **So Cal Mark** » Mon Mar 20, 2006 10:17 am

probably the lower rpm. At lower rpms the engine is running on the low speed (or idle) jet, then it switches to the main jet

Spiderferg · Post by **Spiderferg** » Mon Mar 20, 2006 10:50 pm

Thanks to Bob for his great advise and this site for putting the discussion together, I HAVE PASSED the smog test. I followed his advise to the letter and now have a license plate and registration.

Here's what we did in three easy steps: 1.) added denatured alcohol in a 1:4 ratio to the gas (I put 1.25g of alcohol to around a little less than a half of a tank approx 4-5 gallons) Cost at Home Depot around $!5.00. 2.) Retarded the timing by twisting the distributor around 1/8 of an inch clockwise. I marked the placement with a dot of nail polish so I could put it back easily once I left the test. 3.) Sat in passenger seat during test and had technician run loaded test in 3rd gear not 2nd to lower the rpms.

The result was dramatic. The allowed load test for CO is 1.65. My initial test was 3.82. The test with the changes and alcohol yielded a mere .41.

All other reading went down too, but the Idle HC went up a little and just made it.

Anyone who can employ this method owe's Bob a huge thanks. An auto repair shop suggested I put a Catalytic Converter on for only $350.00 Yikes...

Thanks again Bob (from my family too- I am easier to live with now) for what I will refer to as "BOBSMOG123" from now on.

The other Bob in Gilbert AZ...

So Cal Mark · Post by **So Cal Mark** » Mon Mar 20, 2006 10:59 pm

adding a cat would not have cured the trouble, and in fact wouldn't be legal either. Cats won't reduce CO that much and in fact wouldn't last very long with a mixture that rich. In fact you'd quickly overheat the cat. If you've ever seen a cat glowing red under the car, it's quite a sight.
I'm surprised they let you adjust the timing that much. Here in Calif timing has to be within 3 degrees of factory spec. Retarding timing will cut HC, but usually has the opposite effect on CO

Does your car have a non-catalyst tag on the door frame? The reason I ask is that in 78 catalysts were required by federal law. It was only 76 that federal cars were non-cat while Calif cars required them

Smog failure

Smog failure

KUDOS to BOB, PASSED SMOG