Questions and Answers

Ford Ranger Eating Coils Q. I have a 1996 Ford Ranger 6 cylinder 3.0 engine, automatic transmission, 41,000 miles, fuel injection and ABS brakes. My car broke down and from prior experience, I thought it was the fuel pump. It cranks but it sounds like no gas was going in. The ignition coil have been shorting out and it won't start the car.

When it first happened it was blowing out the fuse. The fuse would blow even if we didn't start the car. As soon as we replace the fuse it would blow again. We replaced the Ignition Coil and the car started, but it only ran briefly for about five miles. This time the fuse didn't blow. The car would still run but it jerks like it's running on only four cylinders instead of six and there's a bad smell coming out of the exhaust.

The mechanic showed me the ignition coil and showed a crack on the plastic case. he said that the first one we replaced had a similar crack on the same spot. He said that he hooked it on the diagnostic computer and there is a surge of electrical power that is shorting out and damaging the ignition coil. We're trying to figure out what is damaging the ignition coil. Could it be just bad wires? or the main engine computer? He suggested the alternator but I doubt it.

Thanks,
Chet

A. The best thing to do is to put the engine on an Ignition System Oscilloscope. This is the only way you can see what exactly the firing voltages are and if any are excessively high. It will allow you to look at both the primary and secondary side of the ignition system.

If the wires or plugs are bad, they could cause the coil to fry. I would also make sure when you replace the coil, you use plenty of dielectric grease under it to transfer heat away from it.