I have no idea what is causing my car to fail the emissions test now. First time it failed due to too many hydrocarbons in the exhaust. I thought this was becuase it is running too rich, so I leaned out the carb all the way. Well, I got it re-inspected today, and there was almost no change at all, in fact, the hydrocarbons went up a little. I already know that it burns a little oil becuase the valve seals and guides are leaking, but could that cause it? My dad is pissing me off saying that it has nothing to do with oil, though, but if im not mistaken, both oil and gas have hydrocarbons in them, dont they? Bottom line is, what is causing me to fail?

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1983 Pontiac Firebird SE
LG4-Based Chevy 400
700R4 Tansmission
Modified 4 Barrel Q-Jet Carb
Accel Super Stock 8mm Wires
Edelbrock Pro-Flo Air Cleaner
3.23 Posi Rear
14X7" Cragar SS/T Wheels
35X4 CD/AM/FM Head Unit
100WX2 Amp
2 Pioneer 12" Subs in Custom Box

 

You are correct, oil burning will in fact cause a car to fail the HCs.

Put a new cat on it. Then, when you go through, hold the motor at about 2500 RPMs or so for a couple of minutes as close as possible to the time it will be tested, to make sure the cat is at operating temp. Having the AIR installed and operating helps too, though it isn't absolutely necessary.

My 83 with a 400 (282 roller cam, Holley 800 carb, etc.) goes through in TN like that, far below the 83 spec (1.2% and 220 ppm). It usually does something like .1-.2% and 65 ppm. I live in CA now though, it'll be fun to see what it takes to get it passed out here. Fun like hemorrhoid surgery without anesthetic I'm afraid.

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"So many Mustangs, so little time..."

 

High HC can be caused by a LEAN mixture, vac. leak, bad cylinder, etc.

HC is basically raw, unburned fuel.

Oil does't show up on a smog test. You could be smoking like a train and pass smog. A truck I smogged just the other day uses a qt. of oil every other day......still passed. Smoked through the whole test.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited September 27, 2000).]

[This message has been edited by Engineboy (edited September 27, 2000).]

[This message has been edited by Engineboy (edited September 27, 2000).]

 

Be sure the oil in the engine is fresh and add a bottle of gasoline antifreeze to the gas tank($1.50 at the local auto parts store). I did this too my Cavalier recently after it flunked badly and it got me through the second time around easily.

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"84Z28/'91 305TPI comp cam flowmaster TB coolant bypass/shutoff valve to heater core MAT relocated Ram-Air(home-made) gutted air-box IROC ground effects/wheels GY245/50's 700R4 superior shift kit/ corvette servo(excellent shift kit BTW) Rebuilt engine and transplanted it myself. Love this engine!
LOW performance people should drive low performance vehicles!

 

A good fresh oil change is good advise.....DIRTY oil will show up on a smog test, BURNING oil won't.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

Engineboy is on the right track.
Rich mixture produces high CO, not high HC.
High HC comes from excessive combustion chamber heat, produced by lean mixtures, ignition timing too far advanced, or ineffective EGR.
Contributing factors include ignition miss, producing incomplete combustion.
Give it a complete tune-up, plugs, rotor, cap, wires if necessary, fuel filter, air filter. Back your timing down to at or below stock specs and make sure the EGR is functioning.

 

Something to keep in mind about adjusting your timing...keep it close to spec.

In CA you can have it + or - 3 degrees on some vehicles, others have to be exactly spec.

Check with your local smog guy.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

 

A few things to touch upon.
A too rich mixture will yield both a high CO reading as well as a higher than norm HC reading. A lean mixture can lead to lean misfire, this will result in low CO reading but high HC reading.
Ineffective EGR and high combustion chamber temps will cause high NOx readings.
Incorrect heat range plugs can have a dramatic effect on combustion characteristics. Too cold a plug can lead to incomplete combustion, leading to high CO readings and higher than normal HC readings. Too hot a plug can create a pre-ignition event and will produce extremely high HC readings.
A few other things in regard to high HC causes: really dirty oil, longer than stock duration cam, dirty air filter, and the lowly PCV valve can crank up the HC reading quickly.
That said, I'd recommend you check your state of tune, fix/replace any poor ignition components as well as anything mentioned above, and then add some octane booster and two bottles of gas line antifreeze to a nice full tank of 93. Take a nice quick blast on the highway and then bump your idle up to about 200 rpm above stock.

 

It would be helpful to know your CO/HC numbers & test mode (low idle, etc??). However, the biggest player to getting HC lower is the AIR pump. I'm not familiar with your particular car, but on other makes, the vaccum that operates the AIR valves run through various electrical solenoids, which are usually failed. Run a direct intake manifold vaccum source to your air valve & make sure the valve opens, allowing air to be pumped to the cat. If you're just missing your HC target, retarded timing will help.
Regards, FJK
PS: The other posts that say oil burning will not affect your emissions are correct.

 

fjk is not correct (sorry buddy) The airpump isONLY finctional during startup and warm up. after ur motor reaches operting temp, the air pump ONLY pumps freash air to the cat. If you have an aftermarket cat, chances are the cat doesnt even need the extra oxygen to help maitian temp. so the air pump is not really of any concern. unburnt fuel is CO primarily and will contribute to some HC.. but generally speaking, i have always understood hc to be un burnt hc's, which is in the form or fuel or oil...hc is lack of combustion.. sooooo IT S NOT THE AIR PUMP... ( i could scan the operation of the air pump from my book if necessary!)

Steve

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86 Firebird, LG4, t-tops, 2.73 open rear, SLP 3 inch cat back exhaust, catco cat, Coming mods: GOT A 350 IN THE WORKS BABY! gonna throw my TES edlebrock headers on it, and hopefully get some more gear and the cowl hood on

My Webpage- Battle of the birds, My own Thirdgen Page, still under construction, http://www.geocities.com/soares711/index.htm

88 Firebird Formula- deseased 2/9/99- 305 TPI, SLP 3 inch exhaust, SLP Intake runners, SLP cam, 3.45 BW disc brake posi, WS6, NOS, and all that good stuff, 13.8 on the motor, 12.89 on NOS and slicks! Hit by what else!?!? a FORD EXPLORER!!!!!!

 

Lets get back to basics...I'm with FJK on wanting numbers....How high were you??

What are the limits there??

What is your timing??

You could just be a good carb adjust away from passing.

As stated above, you can sometimes run the idle up and alot of problems go away. Keep in mind though, the test does have a RPM limit that the car can't excede. (here its 950 RPM)

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited September 28, 2000).]

 

I only failed the idle HC test. The spec is 220, and high speed was 77, but idle was 356. BTW, i changed my oil about 30 minutes before i got it inspected. It might be my timing, though, I will retard it some. Also, im pretty sure my EGR valve doest work. I probalby should richen the mixture some, too.

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1983 Pontiac Firebird SE
LG4-Based Chevy 400
700R4 Tansmission
Modified 4 Barrel Q-Jet Carb
Accel Super Stock 8mm Wires
Edelbrock Pro-Flo Air Cleaner
3.23 Posi Rear
14X7" Cragar SS/T Wheels
35X4 CD/AM/FM Head Unit
100WX2 Amp
2 Pioneer 12" Subs in Custom Box

 

Ward
I had a similar situation with "another brand" car, with almost the same numbers you are reporting. The only way to get the HC down at idle was to get the air pump flowing at idle as well. HC is unburned fuel (for this discussion) which means all fuel particles did not get consumed during the normal combustion process. The last chance to burn this fuel is in the CAT. So, the CAT needs 2 more elements to do this: Heat & air. The air, per se, does not lite off the CAT, basic exhaust gas temperature does. What really makes the CAT run hot is the fact that it's doing its job, which is combusting unburnt fuel with the help of the air supplied by the air pump. I stand by original response.
Regards, FJK

 

Do you have anybody that you can take the car to and put it on the machine while adjusting the carb?? (a buddy in a shop??)

The problem here is this...you adjust carb, go back...still fails.

You adjust the timing, go back...still fails.

And so on...

I pre-check all smogs before I smog them so I don't fail anybody....I get this all the time.....

Me: "Escuse me, but your car won't pass."

Them: "What do I need to adjust?"

Me: "I can check it out for $79.50 an hour and fix it."

Them: "I can work on this myself, what screw do I need to turn??"

I give them a couple of Ideas and they come back in a couple of days and it still fails.

Them: "I did what you said and it still failed??!! WTF?"

Sometimes a REAL small adjustment will make a world of difference.

You didn't say what the CO was. If it is low than I would try to richen up the carb a little, retard the timing a couple of degrees ,(although in my experiance the timing has to be WAY of for it to make much of a difference).

Bring your idle up to just below whatever the spec is on your printout.

Unfortunately there are lots of variables to the puzzle.

As FJK stated, the AIR system feeding downstream air couldn't hurt either.

All of this is taking in consideration that the car runs PERFECT (no missinag at idle, etc.) If the car has a poor idle because of a miss, nothing you do will lower the emmisions, except repair the miss.

Sorry so long, hope some of this helps.

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ASE Mechanic/Machinist/Smog Tech

1999 NBM Trans Am
1986 Chevy 3/4 ton pick up
1981 corvette
1995 Kawi ZX6R

GO #3

[This message has been edited by Engineboy (edited October 01, 2000).]

 

my advice would be to find an inspection station that dosent give a ****.. give the guy an extrs 20$ to pass your car.

 

One thing that I did that may help here is replace my coil. My father and I both did this on our cars (95 Mustang GT for Pops) and we both also noticed that accelleration is a bit peppier, mainly because more fuel is burnt by the higher engergy spark, leaving less HC. Give it a try.

I got the Accel in cap HEI coil, part number 140013 from AutoZone for $73 plus tax. Do you still have the stock distributor/cap? Or did they have a different coil setup in 83? If so, MSD makes some kick *** coils as well as Accel. See what that does for ya.

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1986 Firebird, LG4 305, bored .040 over, Crane cam, Edelbrock headers, Hooker Aerochamber muffler, loud and fast.

"Gimme fuel, gimme fire, gimme that which I desire!" - Metallica, "Fuel"