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Old 06-11-2019, 03:33 PM   #1
Loco83
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Failed Smog

In the the 36 yrs of ownership her first smog fail
Took the truck in this morning for her Biennial test and she failed.
HC (PPM)
Max Meas
135 172

CO%
Max Meas
O.95 1.26
Did the tune up, plugs, cap/rotor, air filter, cleaned out the PCV valve and oil change. Sprayed the E4ME Qjet out with GUMOUT as well as spraying down the throats with the engine running. Took her out on the highway for a 10 mile high speed run at 70, no joy.
Tech suggested a carb adj, and new plug wires.
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Old 06-11-2019, 03:52 PM   #2
Killer Bee
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Re: Failed Smog

yep, adjust carb and check for vacuum leaks, both no charge

wires would complete your recent tune-up but you should go back and inspect the new components as well..

if the engine is otherwise healthy [good compression], may be time for a cat..

even if that's not the sole cause, may improve the tailpipe test adequately to pass

good luck!
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Old 06-11-2019, 04:31 PM   #3
fordguy40
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Re: Failed Smog

I've always used a couple of bottles of gas line antifreeze in about 1/4 tank before I go in for smog tests.
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Old 06-11-2019, 05:05 PM   #4
Ziegelsteinfaust
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Re: Failed Smog

MSD boxes and the like can help too.
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Old 06-11-2019, 07:49 PM   #5
KrazyRay
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Re: Failed Smog

Put in a sleeve of Lucas Oil fuel injector cleaner in the tank with 87 octane gas and you will pass.
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Old 06-12-2019, 11:03 AM   #6
rpmerf
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Re: Failed Smog

Here is a 5 gas chart to help understand how changing your tune will change emissions.



I would say it is running a little rich. Certainly check all vacuum lines and set the idle mixture screws on the carb. Make sure the choke is fully off. Might look into the EGR valve.
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Old 06-12-2019, 12:17 PM   #7
Loco83
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Re: Failed Smog

Thank you Gents.
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Old 06-12-2019, 12:22 PM   #8
THI
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Re: Failed Smog

Warmer thermostat could also help if you are real close.
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