IGNITION COIL PACK TESTING PROCEDURE FOR 93 1.9 EDIS
1993 Ford Escort
June, 6, 2007 AT 5:31 PM
I've been trying to diagnose the coil pack. Hooked up a universal tester and grounded to engine block and got one blue spark at the initial turn of the key. When I pull the Coil pack harness and use a multimeter and test it at the coil pack connection I am getting no reading on when I have it set on the 20k ohms settting. Also when I pull the spark plug wires from the coil pack I dont get any reading at all at the coils on either side.
Can I still get spark and have a bad coil pack? Engine is rotating but not starting.
Sounds like you tested it right. On the 3 terminals of the coil pack where the wire harness attaches, on the 20,000 ohm scale, measure ohms from the middle terminal and a side terminal. If the reading is not greater than.4 ohms, replace the coil. Measure the same way on the middle terminal and the other side terminal. Should be greater than.4 ohms also. Remember, when measuring ohms with a multimeter, touch the probes together. It's usually.2 or.3 ohms. This is the resistance of the leads. Always subtract that when taking critical measurements.
June, 6, 2007 AT 7:38 PM
Thanks for the feedback, can I get spark with a plug tester and get a 0 reading when I tested it? Is this possible? It would only spark once when cranking the engine with the key. Like I had said no reading with the multimeter and also did a spark plug wire resistance check and they seem okay.
June, 6, 2007 AT 8:22 PM
I'm not sure, but getting a zero reading means there is an open in the coil primary. I wouldn't think you would get any spark. Have you tested for spark more than once and you get one spark every time? Do you get a zero reading testing the coil both ways? From the middle terminal to the sides. Or just on one side.
June, 6, 2007 AT 8:38 PM
Thats mainly why I've asked here. Each time I had hooked up the spark plug tester (universal) and set it for 35-40. Got one light blue spark I am very sure Ive been testing the coil pack right with the multimeter just stumped as to why I could get spark on the tester but no resistance reading. When cranking the engine it will crank normally and give a couple of good putters at first, but when you try starting it again it turns over with no putter.
I havent checked the fuel pump yet as I dont own or can locate a pressure gauge. Car had sit in my garage for about 5 years. Good batter 12.7 volts. But muffler was cracked near the flex pipe but taped up, but that shouldnt keep it from starting would it?
June, 6, 2007 AT 9:30 PM
No, the cracked muffler wouldn't keep it from starting. If your only getting one spark while cranking and that's it, plus testing the coil resistance, I would think the coil is bad. But I know what you're saying, don't want to spend the money for a new coil and still have the problem. I've seen ignition coils that tested ok for resistance, and when they heat up they would open, car would run terrible and stall, then cool off and test ok again. But that's the opposite of yours.