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Question Details Asked:Jun 18, 2009 - 12:21 PMStatus:Closed
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If the car won’t start, check simple things first. To do the simplest checks, you need some diagnostic tools. A digital voltmeter, a fuel pressure gauge and a compression gauge. If you don’t have these you need a mechanic or friend who does:1. Starting -The engine must be turned over by the starter motor with enough speed to catch. For this to happen, the battery must have enough charge, the starter motor and the starter circuit should be OK. Check the alternator with the voltmeter as it has to put out 13-15 volts.2. Fuel- mixed with air should be present in the cylinders; normally, proper air/fuel ratio should be about 14/1. Check the fuel pressure at the fuel rail with a fuel pressure gauge. Normal operating pressure is 50 psi plus or minus 5 psi.3. Spark - there must be a strong spark at the proper moment to fire the air/fuel mixture. Pull a spark plug and hold it against a ground while you turn the engine over. You need to see a fat blue spark. If not, check the distributor, spark plug wires and coils. An easy way to test for spark is with an inexpensive spark tester. This is a device that is readily available at most auto supply stores.4. Proper timing - the engine valves should open and close in appropriate time. Check the timing belt and look thru the oil cap opening for the turning of the camshafts. . If the compression is very low on all cylinders (see compression test below), that is a sure sign that the timing belt (or timing chain depending on the engine) has failed and will have to be replaced. 5. Compression - normal compression in the cylinders is 140 - 160 psi. The engine won’t start if the compression is lower than 70 - 80 psi. Between 80 and 120 psi, you will experience hard starting, loss of power and rough running.If the engine won’t start - there’s no magic - one of these things is probably missing. Most commonly it’s a spark or fuel related problem.
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