Re: Serious wiring difficulty and no starting.
a painted surface will almost always not conduct. It has to be unpainted metal, cleaner the better. A bolt threaded into the engine is the best, wire brush or sand the head of the bolt so there's no paint or rust on it. Couple places easily accessible are bolts on thermostat housing, base of carb, intake manifold bolts, sometimes exhaust manifold bolts depending on type of manifold.<br /><br />to test the coil, forget about the spark plug. take the coil wire, which goes from coil to center of distributor, and hold it or place it about 0.020" from a clean piece of metal on the engine, the bolt head I'm talking about. Crank engine over and you should hear and see spark jumping from coil wire to engine block. If you place wire contact on the metal, then there will be no spark jump, obviously, and if you hold it too far away then the gap will be too big and no spark. You need to hold it < 0.050" or so to metal. Once you verifiy the coil is outputting spark, reconnect coil wire to distrib.<br />Again, you can try observing spark at the spark plug with the plug removed from the engine, but the metal outside of the plug, the threads that screw into the head and what the spark plug socket turns on, needs to be touching a clean metal spot on the engine otherwise you won't see no spark.<br /><br />I have pertronix for a ford, only difference I know of with chevy is the rotor style but I think it all works the same: pertronix red & black wire coming out from under distr. cap goes to + & - side of coil, repspectively. When you turn your ignition key on, that sends power to the + side of coil. You're new alternator with internal regulator will have a heavy red wire coming out, that's where all the current comes out on. That can theoretically go anywhere on the + side of the whole electrical system, but it should go somewhere that can handle high current such as the fat post on the starter solenoid where 6 guage wire or bigger goes to from battery, or directly to the battery, or it may directly splice in to the 10 gauge wire running from your battery to your ignition switch. The other smaller wire, not sure which color, out the alternator is what's called a sensor wire. Because the alternator can output 14.0v at the alternator output terminal, it can only be say 12.0v for examples sake, when that power gets to the battery terminal due to length of wire and wire connections it has to travel through along with especially other loads placed on the system and where the alt. current output feeds into the electrical system. So the sensor wire connects to or near the battery to monitor voltage there, so if it sees the alternator charge at the battery is only 12.0v, the alternator increases voltage output at it's output terminal to 16.0v to make up for the 2v drop so voltage at the battery is 14.0 and it charges. For simplicity, you can hook the sensor wire up the same place the big alt. output wire goes to, or right to the output post on the alternator- it defeats the purpose of it but if all you're connections are clean and good it will be fine.<br />You may have a ground wire coming out the alternator also, check the instructions or with manufacturer of that alternator, if it's a ground then all it does is go to a clean ground point anywhere on the engine- the alternator is technically grounded through it's frame when it bolts onto the engine, but the wire is for a clean no resistance connection to ground so the alternator regulator can measure voltage properly.<br /><br />One reason you may not see spark is the wire on - side of coil is constantly going to ground through a shift interrupt switch. make sure that's working properly. other problem may be tachometer, there's a wire from - side of coil. if that's shorting to ground or the tach is bad that will cause ignition problems, you can just disconnect it for troubleshooting, engine will run fine just tach gauge won't work. If you hook up tach wire to coil and have problems then you know it's a bad tach or tach wire.
<br /><br />the backfiring might be caused by having an improper firing order, so check to make sure the wires from the distributor are going to the correct spark plugs. It's easy to mix up.<br />When starting the engine and it backfires, have the distrib. loose so you can turn it. Turn it a little bit one way, if engine doesn't run better then you're turning wrong way. Turn little bit other way and it should run smoother, you'll need a timing light to set the ignition timing properly, 10 deg BTDC at 600-800 rpm.<br /><br />when you checked the spark of the spark plug, were you holding the threads of the plug against unpainted metal of the engine block or just up in the air? You need to ground the plug to observe it spark, when not in the engine.
