On Duraspark II distributors there are two springs on the centrifugal spark advance. This is under the stator plate assembly. If one of the springs is still in place the loose one goes on the opposite side (180 degrees) from the first one.
From '84 shop manual code 48 is a "fuel control" code. They run through tests of the EGO sensors and circuits. The fuel injectors balance and leak down. Shorts to voltage in an injector circuit.(holding an injector open all the time). The fuel pressure regulator.
A rotary file is the same principle as the dremmel only on a larger scale. They would have a 1/4 inch shaft and be all steel. You would use your regular power drill. I have not bought one in a long time but I would not think they would be more than 3 or 4 dollars.
The studs are not attached to anything. They are a swedge or very tight fit. I would have thought they would break off before they would spin, but maybe I am wrong.
Emissions Repair Tips CO too high = Car runs rich, burns too much gas. Bad carburetor adjustment, float too high, carburetor flooding, sticking secondary throttle, leaking fuel injector, leaking fuel pressure regulator, feedback system malfunction (oxygen sensor, coolant sensor, throttle position sensor), emissions vapor system malfunction (purge valve, canister clogged) Be aware that NOX will RISE after you fix a CO problem. This must be checked after a successful CO repair.
HC too high = unburned fuel in exhaust; car runs very rich or very lean. This is the trickiest condition because there are different causes. If the car is running rich (high CO), the HC can be high also. If the CO is very low and HC is high then the vehicle has a lean misfire.
If The CO is high, fix that problem first. If CO is low and HC is high look for engine skipping, misfire due to vacuum leaks, ignition timing set too high, ignition problem (plugs, wires, cap), carburetor adjusted too lean, leaking egr valve. If you can’t find a reason for the high HC then perform balance test then compression test.
NOX too high = NOX forms in normal combustion. NOX too high indicates high combustion chamber temperatures or malfunctioning post-combustion emission controls.
CO and HC must be normal before attempting to repair NOX failure. Anything that can create high combustion chamber temperatures will make NOX reading high. Engine overheating, air cleaner hot air door stuck closed, egr vale not functioning, clogged egr valve passage, lean fuel mixture, ignition timing set too high. The two main systems that reduce NOX on a car are the egr system and catalytic converter. If your car is pinging, the NOX will be too high. Pinging is a symptom of high combustion chamber temperature. If all the test readings are just a little too high (slightly high CO, HC, and NOX) it is likely the catalytic converter is damaged or empty. If your converter is supposed to have air injection and it is disabled, the converter will not function properly.