Will crank but will not start

JASONAAAASSAA

MEMBER
2004 CHEVROLET AVALANCHE
5.3L
V8
4WD
AUTOMATIC
101,000 MILES

I was driving home and the truck just shut off as tho I ran out of gas. The fuel pump is running and I just replaced the crankshaft sensor and still won’t start. It’ll crank over but not start. I don’t think it’s getting spark now. Any idea?

Sunday, September 15th, 2019 AT 3:30 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Welcome to 2CarPros.

Most times it is either no spark or no fuel. Do me a favor, first look through this link to see if anything helps.

https://www.2carpros.com/articles/car-cranks-but-wont-start

Also, I would like for you to check for both spark and the fuel pressure. Even if the pump is running, it may not be producing what is needed to run the engine. Here are a couple links to help:

https://www.2carpros.com/articles/how-to-check-fuel-system-pressure-and-regulator

https://www.2carpros.com/articles/how-to-test-an-ignition-system

Here are a few links you may find helpful when checking for spark:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

https://www.2carpros.com/articles/how-to-use-a-voltmeter

https://www.2carpros.com/articles/how-to-check-wiring

Now, if you would rather bypass the testing, see if it will start using starting fluid. If it does and runs for a couple seconds, then we know it is a fuel related issue. If it still doesn't, then you need to check for spark.

Once we determine which is missing, then I will know what to tell you next. It could be a pump or there have been issues with a common ground strap for all coils failing and causing no spark.

Do this and let me know what you find.

Joe

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Sunday, September 15th, 2019 AT 3:52 PM

JASONAAAASSAA

MEMBER
2 POSTS

It’s not getting spark that’s why I replaced the camshaft sensor thinking that could have been the problem. But still no spark.

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Monday, September 16th, 2019 AT 4:35 AM

JACOBANDNICKOLAS

MECHANIC
109,885 POSTS

Welcome back:

If you have no spark, my first suspect is the crankshaft position sensor. If you have a live data scanner, see if there is an RPM signal (200 to 300 RPM) when cranking the engine.

If there is an RPM signal, I need you to check the one common ground for all of the coil packs. It is located on the left lower portion of the engine (driver's side) and they are known to fall apart. If that happens, you lose spark to every coil.

It will be a black wire and the connector it goes to often times will fall apart in your hands when you touch it. Check that. I attached a pic of the ground location. You will see it is for all coils. And this isn't an uncommon problem. Plus, don't depend on checking for continuity because it may show a false positive.

Let me know what you find.

Joe

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