zbeeblebrox

Ok so i failed CA smog in my 87 944/NA which i figured was very likely. Question is what do i do now to get it to pass? I was thinking a new cat was in order at least but what else? I did an oil change and fuel additive within the last week and drove the car about 350 miles since both. Also Drove car before test to warm her up.

Rogue_Ant

HC was high, and CO as well. Good news is that your NOx was low.

The car is running way too rich.

How long did you warm-up / drive the car before testing? If you can touch the tail-pipe, it isn't hot enough.
What is the condition of your O2 sensor?
What FQS switch are you running?
Is the car chipped?
What fuel pressure?

It is possible the cat isn't working, but most likely the car is just in an overly rich tune.

zbeeblebrox

Drove the car for about 25-30 min. Aside from that the car is stock. Have Never touched the o2 sensor though and no clue what the fuel pressure is.

Rogue_Ant

How about the FQS switch?

O2 sensors do have a life-span. As they age, they tend to get slower responding. Eventually, they will quit working all-together. When this happens, the DME interprets it as a lean condition, and starts adding a bunch of fuel.

Additionally, a California car should have a coding plug installed on the DME harness near the DME. On the factory chip/software, this tells the computer to be more aggressive with its closed-loop response (to help emissions).

Aeropooch

I failed my CA smog as well- passed after replacing the O2 sensor and had to replace the cat.

odurandina

the horror of having to deal with that ****.

my heart sincerely goes out.

i'm never having a cat or smog test ever again by God.

william_b_noble

if you have the original CAT, that is probably weak or dead. any decent shop can check it

ibkevin

Start with o2, go back for your free retest, if you fail - look to the cat. Rogue is correct, your o2 is the first stop to check your rich condition.

The '44 gearing does not play well with the rolling dyno, you basically lug the engine and thats halfway to a fail right there. If you could sell the tech that its an auto trans - it would sail through.

Also, keep the car running until the test. When you get home, put the new cat on the shelf and reinstall the gutted old one.

I've done my time in the smog ring, CA doesn't give a crap how much $$$ you spend on a smog nor how many work hours you lose. If they really gave a crap about air quality, any configuration that passes spec would work.

ehokana

Ibkevin- you hit the nail on the head. My turbo has cut it close a few times but I've made it through. I'm really starting to miss my '73 914 since I didn't have to worry about smogging it.

PerceptionProblem

There's a lot of good stuff in this thread. I'm gonna add my $.02 as well, having had to fight CA SMOG as well.

-Replace your vac lines. All of 'em. Not only are they old (unless you've done them lately) but you'll see better performance from your engine. If you have one leak, you've got more just waiting to show up.

-Don't forget about your EVAP system. That's something that's being tested as of this year and is a serious pain in the ***. The charcoal canister is in the front driver fenderwell, but the lines snake across the bay and head back to the gas tank under the passenger side. (There's a little vac line between two hard lines hiding down there too)

-Change your oil, oil/air filters, and plugs. Always a good idea, but think of it like brushing your teeth before going to the dentist. Lol.

I hope that, along with a new cat and O2 sensor help you pass!

Legoland951

It has been a while since I frequented rennlist. The one single most important in passing smog is the flow meter adjustment. If you are running too rich, disconnect the O2 sensor, pop off the top cover to the AFM, and adjust the the air/fuel ratio by turning the dial. The simplest way is to rev the car to 2k rpm and turn the dial until the RPM is at the highest (it will increase/decrease depending on which way you are turning).

My smog guy is awesome. I can have the car on his dyno in pretest mode while I adjust the AFM until the readings are within passing limits. 95 percent of the time, it is not the O2 that causes the car to fail smog. To make a point, I passed CA smog with a hollowed out cat for the HC and CO but couldn't pass NOx with the O2 DISCONNECTED.

McCrazy

My 84 944 failed CA smog a few years back. I replaced the cat and the O2 sensor and passed no problem.

Legoland951

The problem is a good enough cat will mask all kinds of problems. The car can run rich and the cat will burn off the excess fuel until the cat gets destroyed prematurely because of excessive temperature from having to burnt all that extra gas off.

It is better to fix the root problem if it is running rich by proper adjustment. Also, your gas mileage and drivability will improve.

PerceptionProblem

Legoland951 has good info. I totally forgot that trick!

azbanks

Failed Arizona retest

1990 S2. K&N cone filter in place of the factory airbox. Everything else is stock(oh how I wish someone, anyone(in Colorado maybe) would make a MAF kit for the S2)

I failed the first test so I changed the FQS to setting 5 and added 6 oz of acetone and completely filled the tank. I ran it a while on the freeway to get it hot. The readings improved but I still failed.

NOx limit is 2.50, I got a 2.61.

Could I add more acetone and/or go to FQS setting 7?