I took my car in for emission testing and failed, my HC were too high; standar is 1.6, I had 1.83. They said it is unburnt fuel, what system should I check that would cause this? I have a TBI setup. Thanks for your help.

 

Cat.

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

 

With HC that high you're looking at a new cat...

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85T/A 305/QJ work in progress.

 

I had my cat replace about 2 years or so ago, and about 40,000+ miles. How long are they suppose to last and how can I check it?

 

Sounds like you just had it checked, and it failed.

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

 

Causes for high HC emissions (from Colorado inspection system after a recent failure):
Vacuum leaks, ignition system malfunction, faulty computer controls, air injection system failure, incorrect engine timing, incorrect engine idle speed, improper fuel injector operation, internal engine problem, inoperative/missing catalytic convertor.

You didn't say when your last tuneup was. A set of plugs along with wires, cap & rotor most likely will help. Make sure your AIR pump is working and injectors are not leaking. A new O2 sensor can't hurt. If you've had a misfire or over-rich condition for the last 40k/2 years, then you'll probably need a new cat.

I failed high CO on my van (HC & NOx were fine). It has always either just passed or failed. I did all of what I recommended above except cat for previous tests: After replacing cat this time, it all dropped dramatically.

The new cat had a card in the box that required the owner and technician to sign (I signed both lines, since I replaced it myself), saying that the cat is an emissions control device that normally does not wear out - true if everything upstream is working correctly.

Do you have free retests? If you get more than one, you might try the other stuff first, then the cat if you still don't pass. If you pass w/o the cat but are still relatively high, replace the cat before it's due again.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.93 limited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LG4 w/LB9 block, ZZ3 cam and intake, WP 305 heads ported & polished, Hooker headers & y-pipe, 3" Catco cat).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & Trans-Scat shift kit, 3.08 8.2" 10-bolt w/Powertrax, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

Since you barely failed. I would recommend first to try this fuel additive stuff at your local parts store, called Emissions Pass. I have a gutted converter and passed using this stuff. Also let the car warm up, take it out on the highway and leave it in drive or if it is a stick, let the rpms get up there and try to clean some of the carbon out of the motor. Just don't go to high and blow your motor, somewhere in the 3000 range is what I ran mine at

 

That "Emissions Pass" or "Guarenteed to Pass" stuff is a detergent, intended to clean the surfaces of the cat. I used it on my "barely failing" van, and it still failed. Why? The cat material was gone from the innards. Besides, I was using a gas additive regularly before that, and the two smelled like they came out of the same container.