1986 Cadillac Deville ignition module

1986 CADILLAC DEVILLE
142,000 MILES • 4.1L • V8 • FWD • AUTOMATIC
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want to know how to tell if it's bad and how to change it. replaced throttle position sensor, both fuel injectors, idle control motor, distributor w/ rotor, spark plugs. now car is turning over but won't crank. wondering if it needs an ignition module now exhausted! please help someone!
Jan 13, 2014 at 5:33 PM
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CARADIODOC
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You're going about this the wrong way. By now you should have figured out that replacing random parts is the most expensive and least effective way to diagnose a problem. To add to the confusion, you haven't described the symptom. "Crank" and "turn over" are the same thing. Are we discussing a failure of the starter motor to crank the engine, or it cranks but won't start and run?

In either case, the throttle position sensor isn't even in the picture yet and won't cause these problems. You know all of the spark plugs didn't wear out at the same time. Throttle body injectors have a very low failure rate, and both aren't going to fail at the same time.

The first thing you need to determine is if there is spark during cranking. If there is, there's no point is poking around in the ignition system. If you don't have spark, we can forget about a fuel supply or injector problem. See if you have spark, then holler back.
Jan 13, 2014 at 6:34 PM