Causes and Fixes for 5.7 Vortec No Spark from Coil

By | October 2, 2021

Fixes for 5.7 Vortec No Spark from Coil
If you have a 5.7 Vortec engine and it is not getting any spark, there are several things that can cause the issue.

This includes the fuses, crank sensor, cam sensor, distributor, ignition module, plug wires, and rotor.

With the many things that can cause a no spark issue, each component will need to be tested or replaced to find the cause.

Having a good spark plug test tool is a good idea as they are low-cost and easy to use.

Many mechanics will hold a spark plug wire close to a ground to see if there is a spark, that does work, but it is much safer and easier to use a low-cost spark plug test tool.

Here is an example spark plug test tool on Amazon
Fuerdi Ignition Spark Plug Tester Wire in-line Diagnostic Tools Automotive Auto Detector Coil Ignition System Test for Automotive

8 Causes and Fixes for 5.7 Vortec No Spark from Coil

  1. Fuses
  2. Fixes for 5.7 Vortec No Spark from Coil Bad Coil Fuses
    The first thing to check is if any fuses have blown.
    Fixes for 5.7 Vortec No Spark from Coil Bad Coil Fuses 2
    For example, I recently had a 1999 Chevy with an ECM1 blown fuse that kept blowing, causing the EMC not to get any power.

    The ECM controls many things, including the spark.

    Wires were causing a ground problem which was blowing a fuse and causing no spark along with other problems.

    Once the shorted wires were fixed, the truck got spark and was back up and running.

  3. Crankshaft Sensor
  4. Fixes for 5.7 Vortec No Spark from Coil Crankshaft Sensor
    The Crankshaft sensor sends a signal to the computer and tracks the crankshaft position.

    When the sensor goes bad the computer will not get this information and cause problems.
    Fixes for 5.7 Vortec No Spark from Coil Crankshaft Sensor Location
    The crankshaft sensor is located at the bottom of the engine near the harmonic balancer.

  5. Camshaft Sensor
  6. Fixes for 5.7 Vortec No Spark from Coil Bad Cam Sensor
    The Camshaft Sensor, like the crank sensor, sends a signal to the computer for the position.

    When it goes bad, it also causes issues with the spark.

    The Camshaft Sensor on the 5.7 Vortec is located in the distributor under the rotor cap.

  7. Spark Plug wires
  8. Fixes for 5.7 Vortec No Spark from Coil Bad Plug Wires
    The spark plug wires and coil wire can cause problems with the spark, especially if they are very old.

    Often, very old failing spark wires will have a few that work and a few that don’t.

    An old bad coil wire going to the distributor will cause a no spark problem.

  9. Rotor
  10. Fixes for 5.7 Vortec No Spark from Coil Rotor
    A worn-out bad rotor can also cause spark problems.

    If it looks to be in bad shape, it is usually best to replace it.

  11. Distributor

  12. A worn-out or bad distributor will not allow the spark to pass through to the spark plugs.

    Each plug wire can be tested along with the coil wire going into the distributor.

    Like the rotor, if it is old and worn out, it is usually best to replace it.

  13. Bad Coil
  14. Fixes for 5.7 Vortec No Spark from Coil Bad Coil
    The coil may also be bad and can be tested to see if there is a spark going to the distributor.

    Many mechanics will test if by holding it close to the ground having a helper crank the truck over and see if a spark jumps to the ground.

    Using a spark light tester is much safer from accidentally getting zapped.

    The main thing is to see if the coil is sending out a spark.

    Keep in mind while rare, sometimes a spark can be seen but is weak, which can cause no-start issues.

    I have seen this a few times where the coil sends out a spark, but since the spark is weak, it causes problems.

    If the coil is very old, it may be best to replace it, but usually, when a spark is seen, the coil is good.

  15. Ignition Module
  16. Fixes for 5.7 Vortec No Spark from Coil Ignition Control Module
    The Ignition Module can also cause problems when there is no spark.

    On the 5.7 Vortec it is located on the top left side of the engine.


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