Edmunds Answers

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  • zaken1 07/03/09 10:20 pm PST

    The engine must have spark at the right time, fuel, and compression in order to start. One of the most common mistakes people make when they replace the plug wires is that they put them on in the wrong firing order. This could happen if the order was correct; but the wires are all one position off from where they belong. It could also happen if the order was wrong.

    Another likely reason the engine would not run would be that the timing chain jumped out of position or broke. Turn the engine until the timing mark on the crankshaft pulley lines up with the 5 degree BTDC mark on the scale. Take off the distributor cap, and see where the tip of the rotor is pointing. It should point to either the terminal for the plug wire to #1 cylinder; or to the terminal that is directly opposite the #1 cylinder's terminal, on the other side of the cap. If the rotor points anywhere else; then either the timing chain had jumped, or the plug wires are not in the right firing order.

    If the timing chain and the firing order is OK, disconnect the coil wire from the center terminal of the distributor cap, hold the wire with a heavy rag so you don't get a shock; so the end is about 1/4" from an engine bolt, and have someone crank the starter. There should be a steady stream of sparks from the coil wire. If you get good spark from the coil wire; connect the coil wire back on the distributor cap, and take one of the plug wires off a spark plug. Insert a bolt that fits securely into the connector in the plug wire; so that the end of the bolt sticks out beyond the end of the wire boot. Hold the wire with a heavy rag, so the bolt is 1/4" from the engine, and have someone crank the engine. If there is a steady stream of sparks from the plug wire, the ignition system is good. If there were sparks from the coil wire, but no sparks or very weak sparks from the plug wire; either the distributor cap or the rotor is defective.

    If the ignition system checks out OK, try spraying a 2 second burst of starting fluid into the throttle body, while the throttle is held partly open. Then try to start the engine. If it fires or starts briefly and dies; either the fuel pump is not working, or the fuel filter is clogged.

    If the engine does not fire with starting fluid, but all the above tests turned out OK; the ignition switch probably has excessive resistance, and should be replaced.

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