If you have a 5.7 Vortec engine and it is not getting any spark, there are several things that can cause the issue.
Problems include 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.
8 Causes and Fixes for 5.7 Vortec No Spark from Coil
- Fuses
- Crankshaft Position Sensor
- Camshaft Position Sensor
- Bad Coil
- Rotor
- Distributor
- Ignition Module
- Spark Plug Wires
The first thing to do is check is if any fuses have blown.
For example, I recently had a 1999 Chevy with an ECM1 blown fuse that kept blowing, causing the EMC to not 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.
A bad Crankshaft sensor can cause a no spark problem.
The Crank sensor sends a signal to the computer and tracks the crankshaft position as it spins.
When the sensor goes bad the computer will not get this information and cause problems.
The crankshaft sensor is located at the bottom of the engine near the harmonic balancer.
The Camshaft Sensor, like the crank sensor, sends a signal to the computer for the position of the cam.
When it goes bad, it also causes issues with timing and cause a no spark problem.
The Camshaft Sensor on the 5.7 Vortec is located in the distributor under the rotor cap.
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.
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.
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.
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.
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.
On the same page and problem. Gonna check fuses again-ecm. All new parts except crank sensor. Started the other day after sitting 60 days, then took a dump on me. I don’t get it, persistence will repair it.
ive replaced every electrical component on my 97 chevy 5.7 vortec. the wires had shorted and i had no power i fixed the wires now i got power to everything in the cab but no spark coming from the coil, so i need to go over each fuse again.
I have a 98 5.7 with no spark. I’ve replaced every sensor and part that is associated with the spark and still have no spark.i replaced the distributor and key switch tonight . Please can someone help
If you have replaced everything, it likely is in the wiring somewhere. I would get a diagram of the wiring and start tracing the wires.