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I failed emissions on my 85 pick up

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Old 08-10-2007, 01:51 PM
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Default I failed emissions on my 85 pick up

I just got back from the inspection station and I failed my emissions test. The guy said it was 5x higher than allowed. I was planning on putting on a new exhaust soon anyways. But, how much will this help with the emissions??
I was thinking headers and true duels, with 2 cats. I probably could use a good tune up also.
Any suggestions??
Please
Old 08-10-2007, 01:56 PM
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If it's 5x higher then you're probably running real rich or your cat is long gone. What was 5x higher, hydrocarbons or CO output?
Old 08-10-2007, 02:46 PM
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The CO% is the bad one. The HC's aren't too bad.
I am pretty clueless when it comes to carburators and tuning them. Do you think and adjustment would fix this?
Old 08-10-2007, 10:11 PM
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If you failed for CO, then the truck is running rich...there are a number of things that can cause that. Is your truck a 305 with a feedback Rochester carb? Believe it or not, it's ECM controlled and relies on an O2 sensor like our fuel injected trucks...you could have a mechanical problem, carburetor issue (MC [mixture control] solenoid), exhaust issue giving the O2 sensor an incorrect signal, bad O2 sensor, old tune up parts, catalyst or AIR fault,...etc.
Old 08-11-2007, 12:56 AM
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Originally Posted by budhayes3
If you failed for CO, then the truck is running rich...there are a number of things that can cause that. Is your truck a 305 with a feedback Rochester carb? Believe it or not, it's ECM controlled and relies on an O2 sensor like our fuel injected trucks...you could have a mechanical problem, carburetor issue (MC [mixture control] solenoid), exhaust issue giving the O2 sensor an incorrect signal, bad O2 sensor, old tune up parts, catalyst or AIR fault,...etc.

I don't think I have an ECM or O2 sensors. Yes it is a 305, not sure which carb.
I do know it's "ticking" pretty bad, and running pretty rough.
My new exhaust is on the way(the one stated in the post above) I am also going to "try" to adjust the carburetor this weekend.
I hate when I have too many things that could be wrong. Any more suggestions??
Thanks for the replies. Keep'em coming
Old 08-11-2007, 06:45 PM
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Default Emission Hints

Just like he said. It could very well be the Carb. I would check the timing, vaccuum leak test everything, and look into rebuilding the carb. It might sound like a lot but it might help with the problem. Get a can of Power Tune from any Mercury Marine boat dealer or go to the Mopar dealer and get a can of decarbonizer. Run the engine at 1300RPM and spray it through the carb until it kills the engine or can runs out. Shut off engine if it didn't stall and let it sit for 15-20 mins. Start it back up and take it for a Hell Run down the road. A lot of smoke will come out so don't worry. It's normal. Buy a set of ACDelco Rapidfire plugs, a good brass terminal cap/rotor, and good wires. After all this is done. Change the oil and get it inspected. It should pass emissions.
Old 08-12-2007, 09:00 AM
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sounds good, I'm going down to mess with it right now.
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