Failed emissions test
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Joined: Apr 2012
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Failed emissions test
Hey all, I just joined to see if I could get some advice. I have an 86 Bronco. 5.0, 302, 8 cylinder, etc. I have been having a heck of a time trying to get my vehicle smogged here in California. Recently, I passed the emissions test but failed the EVAP test due to the vent hose above my fuel tank having a leak. I fixed the issue, passed the EVAP test, but then the truck failed the emissions test horribly. I have 2 new catalytic converters installed. I'd like some suggestions as to what I can do to lower the emissions. I don't have much money, and I'm not much of a mechanic, but any ideas are welcome. Thanks a lot.
Postmaster
Joined: Jun 2001
Posts: 2,809
Likes: 3
From: Loveland, CO.
Take the truck out on the highway and drive it at highway speeds just before taking the test. If you just drive it around town then some sort of canister or something gets filled with emissions and makes you fail. It happened to me, they guy told me to take it out on the highway and then come back and he'd test it again, which I did, and it passed with flying colors.
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
Replace air and breather, filters. Make sure the computer isn't throwing any Codes. (Anything not functioning properly within the emissions/engine control system is going to screw with what the "sniffer" "smells"). I'll second JBronco's suggestion to get it up on the highway and RUN it. Blow the excess crud out of it. If you do a lot of city driving and don't get it up to highway speeds often or for extended periods of time, you get a ton of crud built up that will get blown out when they start pushing it on the dyno to simulate highway driving. Blow it out before it gets to the testing facility.
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
Heet is a methanol product which, when combine with water, will "separate" the hydrogen and oxygen molecules into combustable derivatives that will burn off in the combustion cycle. (VERY simplified answer). Enough methanol in the fuel system could feasibly alter hydrocarbon readings. A straight fuel injector cleaner or the ISO-HEET product would be more apt to yield discernible results. (Why didn't I like doing research when I was in school? Its amazing what a few minutes of poking around in books and on the web will yield in the way of answers!)
Post Fiend
Joined: Nov 2011
Posts: 8,908
Likes: 1
From: Algona, Washington
Ya no kidding, the truck we did it on was an 84 bronco though so it was carbed haha. But my brother ended up replacing the carb twice before it passed.. Not sure why though, around that time i was just barely starting to like working on cars.
Lead Driver
Joined: Sep 2002
Posts: 9,182
Likes: 12
From: Gateway to the West
Yeah, getting a carburated engine to pass stringent emission can be like finding that needle someone hid in the haystack. Too easy to tweak an adjustment a hair too far one way or the other and the result is endless headaches at testing time. Missouri actually has a "get of of emissions testing for the year" clause in the law that states that if you have receipts to prove you have spent more than $200.00 to try to get the vehicle to pass, they will waive the requirement for the year. However, to get to this point, you have to spend $200.00 ON EMISSIONS-RELATED equipment/labor AND submit to the test at least three times (and of course they charge you). Its only good for a one-year period though. Gotta be right by the next test or you just won't get it registered.
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Post Fiend
Joined: Nov 2011
Posts: 8,908
Likes: 1
From: Algona, Washington
Ya my brother had a Ford dealership poke at it for a bit and when he got it back it ran a bit rougher, like they leaned it way out then he still failed emmisions, it wasn't untill he replaced the carb and dumped a ton of the HEET stuff in the tank. it was either heet or iso heet i don't remember but i do remember my step dad telling me it helped heat up the engine. Eventually they got it to barely pass, then it was all over with. Last year for his. here in Washington it is 25 years of emissions then no more. My 88 ranger has it one more time next year i think before i can rip the exhaust off. BUT when i get it back from the aforementioned brother, i will probably pull my stereo stuff out and try selling it to my local junk yard. The motor is close to dying and with the way my brother drives it makes me wonder how it has lived this long.
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