Testing a Cranks but Does Not Start condition on your GM 4.3L, 5.0L, 5.7L pick up, van or SUV is not that hard to do, if you have a solid diagnostic strategy. In this article I'll show you the basics of testing such a problem.
I'll also explain some of the basic causes of a No Start Condition, since knowing this basic info will save you time and money... since you'll know what to test and how to test it before replacing it.
Here are the contents of this article at a quick glance:
You can find this tutorial in Spanish here: Cómo Probar un Arranca Pero No Prende (GM 4.3L, 5.0L, 5.7L) (at: autotecnico-online.com).
It's important to know that a No Crank and a No Start Condition are not the same thing... since this article only concentrates on testing a No Start Condition.
In layman's terms, a No Start Condition means that your vehicle's starter motor is cranking the engine but the engine is not starting. This condition is usually due a failed fuel pump, a failed ignition coil, a failed ignition control module, a failed crank sensor, etc... that lets the engine crank (turn over) but does not let it start.
A No Crank Condition means that the engine is not turning over when you turn the key to crank the engine. The most common problem, that causes this condition is a failed starter motor. If your vehicle is suffering a No Crank Condition... this tutorial may be a good starting point: How to Test the Starter Motor (GM 4.3L, 5.0L, 5.7L).
There are three very basic components that the engine, in your GM vehicle, needs to start and they are: Air, Fuel and Spark.
When your 4.3L, 5.0L or 5.7L GM vehicle Cranks but does not Start...it's because one of these components is missing from the mix.
Now, it sucks that your vehicle does not start... but the cool thing is that you can isolate the area where the problem exists and then test specific components within that system. There are three main areas where the problem will reside in and that you should concentrate on when facing a No Start Condition:
1.) Ignition System
2.) Fuel System
3.) Engine Mechanical System
4.) PassLock Anti-Theft System
OK, the list of possible things that can go wrong looks pretty long... but it is rare to see (or have) two different components go BAD from two separate systems at the same time.
The cool thing is, is that there is a diagnostic strategy that you can use to figure out exactly what's wrong with your particular No Start problem. Let's find out more about it in the next subheading...
“I bought a perfect second car... a tow truck.”