1990 Chrysler Le Baron 1990 Lebaron "No Spark"

Tiny
TAKEDOWNRCM
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  • 1990 CHRYSLER LE BARON
  • 4 CYL
  • FWD
  • AUTOMATIC
  • 147,857 MILES
My 1990 chrysler lebaron wouldnt start all of a sudden one morning a few days ago. I figured out it doesnt have spark. Ive changed almost everything there is to change in order to achive spark. Ignition coil, pick-up coil, rotor. I havent changed the dist cap because it looks new and the wires are newer. Why would it all of s sudden not have spark overnight and what else could be the problem?
Tuesday, December 8th, 2009 AT 9:17 AM

3 Replies

Tiny
CARADIODOC
  • MECHANIC
  • 33,743 POSTS
Did you check for fuel spray from the injector or just get "wrapped around the axle" like most people when you found no spark? By "pickup coil", are you referring to the Hall Effect switch in the distributor under the rotor? That is the most common cause of a no-start condition. You will have no spark AND no injector spray, AND the fuel pump won't run. If the rest of the circuit is ok, you might hear the fuel pump run for less than two seconds when you first turn on the ignition switch, then it will turn off again until pulses come from the Hall Effect switch, (engine is rotating - cranking or running).

If you listen right under the fuel tank when a helper turns on the ignition switch, and you never hear the fuel pump run for that two second burst, suspect the Automatic Shutdown (ASD) relay. They don't cause very much trouble, but you can try swapping it with a different one. (Don't swap it with the fuel pump or starter relays. The AC compressor would be a better choice).

Caradiodoc
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Tuesday, December 15th, 2009 AT 12:02 AM
Tiny
TAKEDOWNRCM
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Yes, I replaced the hall effect switch aswell. Bought it used from the junkyard off another lebaron. Dont know if this one could be bad aswell?
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Monday, January 4th, 2010 AT 4:25 PM
Tiny
CARADIODOC
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Ok, let's get down to business. The Hall Effect Switch is a high failure part so it wouldn't hurt to try another one.

The first thing to check is whether the Automatic Shutdown (ASD) relay is turning on. It should turn on for one to two seconds when you turn on the ignition switch, then turn back off. There are a number of ways to tell. You might hear the whir of the fuel pump if the chime isn't too distracting. You can also listen under the fuel tank or by the filler cap when a helper turns on the switch. Chances are you'll hear the pump run since the ASD circuit is very trouble free. If you do hear it, suspect the Hall Effect switch.

If you don't hear the pump, it could be bad or it just might be quiet. GM pumps are pretty noisy; Chrysler pumps are usually very quiet. A dead pump will sometimes start up if you bang on the bottom of the tank when your helper turns on the ignition switch. If banging gets it started, it could work fine for weeks or it could act up again next time.

Another way to tell if the ASD relay is turning on is to use a test light or voltmeter to measure the voltage on the positive terminal of the ignition coil, the wire to the fuel pump, (if you can find it), one of the fuel injector wires, or the small wires on the back of the alternator. All of these should have full battery voltage for one to two seconds after turning on the ignition switch. If you have voltage for those two seconds, that also confirms the circuitry is working.

The engine computer will turn on the ASD relay again when it sees engine rotation, (cranking or running). It knows there's rotation from the pulses received from the Hall Effect switch. If you do find voltage at any of these points while cranking the engine, the Hall Effect switch is working. That's when it's time to figure out why spark is missing. Check if the distributor shaft and rotor are turning during cranking. If not, suspect a broken or stripped timing belt.

Caradiodoc
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Monday, January 4th, 2010 AT 10:24 PM

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