Just bought it from auction for $400, took it to get smogged and failed Gross Polluter levels:
15mph test HC 436ppm, CO 1.46% (specs are 127ppm, 0.78%)
25mph test HC 320ppm, CO 1.28% (specs are 108ppm, 0.99%)
It also failed the ignition timing check because the idle speed was at 1050rpm (spec 750-850rpm)
I want to know if this can likely be fixed without a great expense, if I slow down the idle speed, replace the plugs (and distributor cap, HT leads) and clean the air filter is that likely to help or have i bought an old dog??
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something wrong here
with 99 degrees btdc it will not run
have you got it on the correct plug lead
next the timing is regulated by centrifugal advance if electronic or points and by the crankshaft position sensor if ECM controlled ( some after market distributors that are used in place of points units have a small sensor in the distributor that can adjust the timing according to engine rpms, but it cannot make allowances for mixture and so they can advance the timing but not take into account anything else which sometimes results in detonation under certain throttle settings
so initial setting for most cars is 10-12 degrees btdc at idle and with engine rpms set up to 3000 rms it may advance to 25-30 degrees depending on the advance mechanisms
with ECM units the timing is controlled by the crank position sensor and is set to parameters according to engine rpms and air/fuel ratio settings but it still has a basic 10-12 degrees btdc on starting
to fail smog tests you probably do not have a working cat converter and other problems besides timing
Notice in the emissions part of the service manual. That is has different versions of this truck Canada, 49 state and a 50 state. Not all of them have the egr valve. Some may not have this and in some areas this could cause the truck to fail "NO/PPM" (NOX) on the smog like in LA County. Causing the truck to be viewed as a gross polluter. This reading might be more then double the gross polluter limit allowed.
the smog test looks like the engine is miss firing, that could cause the timing to be out of whack also, try a old fashioned tune up, new spark plugs, wires, and filters also replace the PCV valve. any time you see the NO that high suspect a miss fire.
High HC means moisture in the system. Try driving it longer then take it to the smog shop. Otherwise it could be hard like a head gasket or easy such as a PCV not functioning. Any ways you should always drive it about 20 miles before smog check, longer when the weather is cold.
you may need replace the catalytic converter, but 1st do this, clean the throttle body and idle airbypass valve, change the oil before the retest as well, get it as hot as you can before the test, hold it at a high idle prior to the test, this may squeak you by, as a 20 year smog tech these are the thing I did, if all else fails do the cat conv.