1987 Ford Mustang Loses Spark After Start

1987 FORD MUSTANG
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AHLESTER01
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  • 3 POSTS
ok i am in a really desperate situation, my 1987 ford mustang 5.0, 302, lx, will crank up for about 30-60 seconds, and then die and will not crank up because it looses spark, it has fuel no fuel problem, but will not crank up and looses spark, is this my pcm? or something else?
Nov 27, 2006 at 1:12 PM
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CATCH_15
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  • 250 POSTS
When you say it cranks up do mean that you try to start it for 30-60 seconds or that the idle raises for 30-60 seconds and then the car dies?
Nov 30, 2006 at 6:10 AM
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AHLESTER01
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no it cranks up for 30-60 seconds then stalls
Dec 1, 2006 at 3:24 AM
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1BIGG1
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  • 61 POSTS
does it actually lose spark. youve pulled a wire and checked for spark?
Dec 3, 2006 at 12:24 PM
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AHLESTER01
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yes it does lose spark completely, we tried a new ingnition control module, distributor, coil pack, none of those worked and still no spark
Dec 6, 2006 at 5:46 AM
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CARUNDELL
  • ✓Experienced Mechanic
  • 602 POSTS
[quote:e4957ef01f="ahlester01"]yes it does lose spark completely, we tried a new ingnition control module, distributor, coil pack, none of those worked and still no spark[/quote:e4957ef01f]

Hey ahlester,
Those older fords where notorious for wiring harness/connector issues, additionaly the relay that powers up the pcm have issues too and may be "dropping out" causing your lack of spark AND those relay connectors also get very corroded too (greeny meanies!!)

Regards,

Chris
Dec 6, 2006 at 6:35 AM
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Suggested Repair

Inspect the PCM power relay and its connectors for corrosion or dropout, and check the ignition and PCM wiring harness and connectors for poor connections that can cut spark after a short run.

Conversation Summary

A 1987 Ford Mustang 5.0 starts and runs for 30-60 seconds, then stalls and loses spark completely while fuel remains present. A new ignition control module, distributor, and coil pack did not restore spark. The expert said older Fords often have wiring harness and connector problems, and that the relay powering the PCM can drop out; those relay connectors also commonly corrode and can cause the loss of spark.

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