Not Starting After Ran

All "crank, no start" conditions are approached in the same way. Every engine requires certain functions to be able to run. Some of these functions rely on specific components to work and some components are part of more than one function so it is important to see the whole picture to be able to conclude anything about what may have failed. Also, these functions can ONLY be tested during the failure. Any other time and they will simply test good because the problem isn't present at the moment.
If you approach this in any other way, you are merely guessing and that only serves to replace unnecessary parts and wastes money.



Every engine requires spark, fuel and compression to run. That's what we have to look for.

These are the basics that need to be tested and will give us the info required to isolate a cause.

1) Test for spark at the plug end of the wire using a spark tester. If none found, check for power supply on the + terminal of the coil with the key on.


2) Test for injector pulse using a small bulb called a noid light. If none found, check for power supply at one side of the injector with the key on. (This is difficult with a Vortec so cave it for last)


3) Use a fuel pressure gauge to test for correct fuel pressure, also noticing if the pressure holds when key is shut off.



Once you have determined which of these functions has dropped out,
you will know which system is having the problem.

You only need to check for spark at one cylinder at the time it won't start. The way we do this is we hook up our spark tester and fuel pressure gauge ahead of time. Then we just keep trying the car until it fail and observe if we still have spark and correct fuel pressure. What happens with those 2 functions will determine if you have to test injector pulse also.