The car almost passed smog, but is still high hydrocarbons.
Max 73, measured 79 (15mph)
Max 56, measured 63 (25mph)
That part's ok with me.. Idle is not perfectly smooth. There's a miss.
My maintenance efforts have been minimal at best for years and tons of miles, and I'm sure an oil + filter change (who knew filthy oil can do it) , new plugs, wires rotor and cap will improve combustion and reduce HC.
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Today, the car failed a functional test that it passed last week, namely the Low Pressure Fuel Evaporative Test (LPFET)
My understanding: The tank fumes are vented (hose) to the charcoal canister, and then goes to the intake manifold, whereupon it gets sucked in and burned.
To test: They clamp off a hose (which one?), and put about one PSI (nitrogen) in the fuel tank, and wait a few minutes to check the rate of pressure loss. Loss = leakage somewhere. Rate too high = fail.
Anybody care to opine on why it passed last week but not today?
The tech said he tried 3 times.. underlined ... and exclamation marks on the work sheet.. So, I don't think he messed up today.
If last week's test was a screw-up, how could it pass when it's not supposed to? (tested by the the same guy, btw)
Between the 2 tests, the car was driven ~100 miles freeway, in order to run some fuel system cleaner through it. That's all that happened.
Max 73, measured 79 (15mph)
Max 56, measured 63 (25mph)
That part's ok with me.. Idle is not perfectly smooth. There's a miss.
My maintenance efforts have been minimal at best for years and tons of miles, and I'm sure an oil + filter change (who knew filthy oil can do it) , new plugs, wires rotor and cap will improve combustion and reduce HC.
----------
Today, the car failed a functional test that it passed last week, namely the Low Pressure Fuel Evaporative Test (LPFET)
My understanding: The tank fumes are vented (hose) to the charcoal canister, and then goes to the intake manifold, whereupon it gets sucked in and burned.
To test: They clamp off a hose (which one?), and put about one PSI (nitrogen) in the fuel tank, and wait a few minutes to check the rate of pressure loss. Loss = leakage somewhere. Rate too high = fail.
Anybody care to opine on why it passed last week but not today?
The tech said he tried 3 times.. underlined ... and exclamation marks on the work sheet.. So, I don't think he messed up today.
If last week's test was a screw-up, how could it pass when it's not supposed to? (tested by the the same guy, btw)
Between the 2 tests, the car was driven ~100 miles freeway, in order to run some fuel system cleaner through it. That's all that happened.