Failed CA SMOG - HIGH HC - need help!

[fourdrinie]

OK Guys....
1997 J30, everything stock...156,000 miles on it
failed two year CA emissions test for HC, all others were ok:
15 mph max:50 Ave:9 Meas: 41 (just passed), two years ago it measured 49, four years ago:19
25 mph max 34 Ave: 7 Meas:37 (just failed by three points), two years ago it measured 22, four years ago: 9

What's the steps I should take?

1. plugs are fairly new, but I have a new set that I can put in....
2. will check timing, but PITA to change it...
3. Replace Oxygen sensors? I have ones to replace
4. Try some additive, like CRC Guarantee to Pass?

Advice???

[J30tnoob]

I would deff replace the oxygen sensors esp sinse you already have them. Plus it'll get you a little better millage either way. The plugs probably won't make that much of a difference sinse you already have pretty new ones in. I have heard that the additives are worth the money. And if none of that works then you could have bad catalytic converter(s) or maybe even a bad gasket. But IMO your on the right track with the steps you want to take

[asoomal]

How are the NOx, CO2, CO and O2 readings?

[fourdrinie]

%CO2 %O2 CO NO
15 15.1 0.1 .02 52 where fail is 414
25 15.1 0.0 .02 0 where fail is 701

which I believe means my EGR system is fine, since my NO is low...

[driverdriver]

Is your catalytic in good shape? Check the exhaust for holes. I personally run Octane 93/94 (whichever is available) for emissions tests up here. Filling the tank with the cleanest gas you can buy makes a difference and running the car on the highway for 30 to 40 minutes prior to an emission test also helps.

[fourdrinie]

There are no visible holes in either Cat or exhaust system.
I just changed the two O2 sensors, checked the plugs which were good, Air Filter is very clean...
I added a dose of Chevron Techroline to the gas tank which was full. I always use premium 93 Arco gasoline, which may be my problem....will switch to Chevron ASAP, it might run much cleaner.

[asoomal]

You might wanna run less octane....it'll burn it much easier since your HC are high.

[Victor]

When I just barely failed smog CA smog with my GMC van the guy told me to drive around on the freeway for 20 minutes to get the engine real hot and come back and keep the engine running to keep it hot for my free retest. It worked, and I passed on the second test.

[fourdrinie]

Thanks Victor, I changed my O2 sensors, and on Tues I am going to do exactly that....take a 30-50 mile drive and take a second test!

Will advise!

Here is what Smogtips wrote back after I sent them the Smog Test results and asked them to interpret it:

SMOGSMART VIR REPORT – 1990 INFINITY J30 3.0 LITER ENGINE
SmogSmart Report # 1823567

Your vehicle’s emissions results: High HC at 15/25mph. Possible ignition fault/s. Potential ignition timing concerns. Vehicle did not fail CO, however the low CO numbers indicate a possible lean fuel mixture. Lean fuel mixtures are responsible for a high HC fault, called the lean misfire. If after all emissions systems are inspected, and no faults found, consideration should be given to a possible defective CAT.

How a Lean Misfire causes high HC: The main reason vehicle's fail HC is due to defective ignition components, however if after inspecting/repairing the ignition components, the vehicle still has high HC, the next consideration would be given to the malfunction called the "lean misfire". This condition is created when, for any reason, the combustion chambers do not receive enough fuel, causing the fuel that is delivered to burn improperly and leave behind high levels of HC.

Fuel distribution to your engine's combustion chambers is controlled by your vehicle's ECU(Engine Control Unit) and fuel injectors. In order for your engine to pass a smog inspection, fuel delivery and air/fuel mixture must be preciously controlled to produce the least emissions. If the injectors do not present enough fuel to the combustion chambers, this would cause low CO emissions and high HC emissions. In order for the ECU to estimate the right amount of fuel to distribute, it needs to know how much fuel is currently in the system. This way it can always maintain a proper ratio and keep emission levels at their lowest. The component responsible for letting the computer know how much fuel is in the exhaust system at any given moment, is the Oxygen Sensor. The Oxygen Sensor sends an electrical signal to the ECU, letting the computer determine exactly how much fuel it should continue to deliver to the combustion chambers. If for any reason the 02 sensor (oxygen sensor) does not send accurate information to the computer or it is "lazy" in sending the correct signals, the fuel delivery program can be altered. The computer may then present either too much or not enough fuel to the combustion chambers and therefore cause an emission failure.

It may be possible your engine's oxygen sensor is this not sending the proper signal to the ECU, causing the ECU to send the combustion chambers less fuel then is necessary to keep the emissions at their lowest.

Keep in mind with a computer controlled engine such as this, there are several other components which also play a role in determining fuel ratio. Along with the Oxygen Sensor, several components such as the, TPS (Throttle Position Sensor), ECT (Engine Coolant Temperature Sensor) and the MAP (Manifold Absolute Pressure Sensor) or MAF(Mass Air Flow) sensors also send vital engine information to the computer which is used to determine proper air to fuel ratio. If any one of these components are defective they can alter the fuel delivery program. A smog service station would be able to diagnose each component and report it's condition.

[GerryO]

How's the idle speed? Engine timing is OK?
Cleaning the MAF is fairly easy, inexpensive and could be a good thing to do.
TBs could be dirty. The miles are adding up, meaning injectors are getting old (ohm check?) and PCV tubes are clogging.

Six counties require smog certificates only within certain zip codes: El Dorado, Placer, Riverside, San Bernardino, San Diego, and Sonoma county. Our zip is a Change of Ownership Area.
You may obtain your inspection at any licensed Smog Check station. You will receive the same Two-Speed Idle test you have always received. Your vehicle will be tested for harmful levels of emissions of hydrocarbons and carbon monoxide. Your vehicle must only be tested when sold, or upon initial California registration.

[fourdrinie]

The car runs very smooth....
I cleaned the MAF not too long ago...I changed the passenger side PCV valve about 40K miles ago, I cannot get the driver side off to change!!!
I just checked the plugs, they are clean....replaced O2 sensors....
I would think if the injectors were failing, I would feel some sort of a shake or stumble upon acceleration...not a peep!~
The EGR tubes were replaced at 75K miles, so they should be clean....
I think I am going to take a long drive, about 50 miles down to San Jose and come back and take my retest...
worth a shot?

[GerryO]

Sounds like your car is very well maintained. Am guessing that between the new O2 sensors and the long drive on 280, you'll pass. If my J30 was here with me in SJ, we could have a West Coast meet!

[fourdrinie]

I called my mechanic, Honza from Datsonville, in Burlingame, CA who laughed at how close the test result was! He also noted by the test results, the cats are working fine, but the short drives I have been taking recently have not been enabling the car's computer to effectively burn the HC...he recommended changing the oil and filter, going on the long drive to San Jose and back on 280, keeping the car running and re-testing....going in tomorrow!
Will post results!

[yodawill2000]

I always take a once a week drive on a back road keeping it in 3rd and run to just under redline 4 or five times.
Pass with flying colors every year.
The inspection guy is always amazed at how low the #'s are.
These engines were made to run , not walk.

[driverdriver]

These engines were made to run , not walk.

+1

[fourdrinie]

ok, latest update.....
found PCV valve rubber hoses were both hard, cracked and needed replacing.....got them replaced after a long delay obtaining them from stealership....
meanwhile, ran some cleaner gasoline (always 91 octane), threw in some Chevron Techroline for good measure....and took about a 250 mile drive up to Wine Country to clean it out.....
Brought it into my mechanic to watch the O2 sensors register as clean burning (long term) on his Consult type system. There was nothing wrong with the engine as far as he could tell.
So, I brought it back into CA emissions and I failed again....same HC were up there, this time, 15 mph test was 114 (50 max) and 25 mph test was 71 (34 max)...this was after a 45 minute drive around the SF Peninsula to get the cats hot...

Unless someone has any ideas, I guess I am going to have to bring it into a Gold Shield testing station and run a full gamut test on the cats and emission system.....

[GerryO]

One search result:

A. WHAT CAUSES HIGH HYDROCARBON (HC)?
Below are common failures which are likely to produce high Hydrocarbon HC. Hydrocarbons are basically raw fuel, otherwise known as Gasoline. High Hydrocarbon (HC) emissions are almost always a sign of poor fuel ignition. However, it's not always that the engine's ignition system is responsible for high Hydrocarbon emissions. Read on.

1. Improper Ignition Timing - Engine ignition timing is measured in degrees before or after Top Dead Center (TDC). Example of an ignition timing failure would be in the case where an engine's ignition timing is required to be set at 10 degrees Before Top Dead Center (BTDC) and instead is set to 15 degrees BTDC. This fault will not only cause a smog check "functional failure", but will increase Hyrdocarbon (HC) emissions as well. California allows 3 degrees +/- off of the manufacturer's required setting. Note: Late model vehicle's may not have a distributor, and therefore no timing adjustment will be needed. On these engines timing is electronically controlled by the ECU (Engine Control Unit).

2. Defective Ignition Components Your vehicle's ignition system consists of the ignition coil/s, distributor*, distributor cap*, distributor rotor*, ignition wires, and spark plugs. If any of these components are defective the engine will produce high hydrocarbons. A common reason ignition components perform poorly is due to carbon build-up. High ignition voltage traveling through the air pockets within these components form carbon. Carbon acts as an insulator between paths of electricity, decreasing the energy required at the spark plug to ignite the air/fuel in the combustion chambers properly. *Distributor-less engines do not have these components.

3. Lean Fuel Mixture - Any condition which will cause unmetered air to enter the intake manifold, and ultimately the combustion chambers, will cause high hydrocarbons (HC). This condition is called a lean miss-fire. Such faults as vacuum leaks and gasket leaks will cause lean fuel/air mixtures. Broken, disconnected or misrouted vacuum hoses will do the same. It is also important to note that many engine components rely on engine vacuum for proper operation. If any of these components are defective, externally or internally, they may cause large vacuum leaks as well. A good example of such a component is your vehicle's power brake booster.

4. Defective Catalytic Converter - A defective catalytic converter (CAT) may be responsible for high HC, CO, and NOx emissions. The Catalytic Converter, commonly referred to as the CAT is a component designed to continue the combustion process within itself and emit a more thoroughly burned and less harmful emissions containing exhaust. The most accurate way to find out if your vehicle's CAT is working efficiently is by using an exhaust gas analyzer. Unfortunately this tool is fairly expensive. Testing the CAT should be conducted at a smog check repair station.

Some obvious symptoms of a bad CAT could be any of the following:

a. Major loss of power over 15-25 mph. This may be an indication that the catalytic converter is plugged up and restricting exhaust flow.

b. Strong sulfer or rotten egg smell emitting from the exhaust on an otherwise good running vehicle. This may be an indication that the Catalytic Converter isn't burning fuel completely, instead storing it, then releasing it as hydrogen sulfide.

c. Loud rattle being heard from inside the CAT. This may indicate a broken Catalytic Converter substrate. You may want to insure this sound is not due to loose exhaust components, i.e. broken muffler flanges, loose exhaust pipes, loose or cracked exhaust manifold.

5. Defective Air Injection Components - Faulty smog pump and related emissions system components will cause high HC. The air injection system is designed to introduce additional oxygen, after the metering system, to the engine exhaust as it exits the exhaust manifold, or directly before it enters the Catalytic Converter; thus burning whatever remaining fuel (HC) in the exhaust completely.

6. Low Cylinder Compression - This fault is one of the less common high HC causing problems we encounter. Reasons an engine may have low or no compression in one or more of its cylinders may include things such as burned intake or exhaust valve/s, defective valve guides and/or seals, defective piston rings, and burned head gasket/s. A wet/dry cylinder compression test will diagnose this fault. More then often if such a problem exists it will be very apparent. You should notice rough idle.

Pulled any codes (KS does not trigger CEL and changes timing)?
Verified ignition timing at 15 deg BTDC?
Check plugs/gap/platinum/heat range?
Continue to investigate/fix vacuum leaks?
A dirty MAF element makes the engine run leaner.
Ohm check injectors?
Throttle bodies clean/closing completely?
How old are the O2 sensors?
Imagine clogged EGR tubes might affect readings at higher rpms/intake manifold negative pressures.
Air regulator or IAC not closing completely?

[fourdrinie]

Gerry....as I said, the car runs great....on the trip from Foster city to Calistoga via Santa Rosa, the car got 23-24 mpg...not bad for this car...front O2 sensors recently changed, no codes, just checked the plugs....the car was running on 280 at 80 mph with no problems this am....great idle....grrrr

[fourdrinie]

ok...finally got the chance to bring the J30 into a CA gold shield smog station to get a diagnosis....BOTH cats need to be replaced...good thing I applied for CA state assistance....CA cats are $350 each, the state pays enough to get them installed. Should have the car back tomorrow afternoon!