1950-1966 [Subscribe to Daily Digest] |
Since some of us are being sarcastic, ...get it a jump rope.
Rule number one when dealing with problems: Check all systems in the correct order. The mechanical condition of the engine must be good before checking the ignition system. The ignition system must be in good condition before messing with the fuel system. I've seen perfectly good fuel systems that were completely messed up because people are convinced the the problem is in the fuel system without ever checking the mechanical condition of the engine or the ignition system. I've also seen people spend hours swapping this part and that, when the real problem they are dealing with is not related to the parts they are swapping.
So, the first thing to do is to take a compression check on the engine and check and, if necessary, adjust the valves. Especially on a turbo, which seems to be more prone to blowing head gaskets from what I've heard, do a cooling system check for exhaust gases leaking into the coolant. These tests will assure that your engine is mechanically sound.
Your miss sounds like it is more regular, but I had a customer with a Mercedes 250C many years ago that would skip a beat every once in a while. The rotor and cap *looked* fine, ignition wires were good, points and plugs were new, but it still would miss once in a while. Finally one of his truck mechanics suggested changing the cap and rotor and that cured it. There must have been a minute crack in one of them that would occassionally pass a spark to ground instead of to the correct spark plug.
For various reasons, ignition wires could be causing trouble, too. One rule that I learned years ago that seems to be true is that anywhere that two plug wires cross they must cross at the shallowest angle possible. The closer to 90 degrees the angle of their crossing, the more likely you are to get a misfire between the wires. I think this misfire is somehow related to the magnetic field created when a wire has current flowing through it. If wires rub on anything, the outer covering on them will get burnished and I've found these wires are more likely to misfire, especially if they are rubbing on metal. They also rub together and will misfire, so keep the wires seperated if at all possible. Make sure that you have good wire looms where they cross over the valve cover. Make sure that the wires are the proper length. I've seen cars with long ignition wires draped all over the place and rubbing on everything in sight. Wires that are greasy catch dirt, which in turn absorbs moisture which will cause misfiring. Keep your engine clean and fix any oil leaks. Keep you ignition wires clean; I spray Brakleen on them and then rub them with a clean rag.
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