VATS disables the fuel.

 

Does it disable the fuel pump or the injectors?

 

 

 

I was thinking about that. Seems like if it had enough juice to crank over it would be fine. Is that not right?

 

if it can power the starter (100+amps) it has enough for the fuel pump and ECM who are combined ~30amp worst case scenario.

 

Not always. I've had a few cars with weak batteries crank the engine but not have enough left to fire the coils hard enough. And that will be more of an issue the colder it is. (harder to light off fuel the colder it is so you need all the spark you can get)

Does it crank over real strong? Or does it sound a little weak?

I was at AMP a few weeks back and a guy brought a 2010 truck in because it would randomly run bad after starting it. It had a weak battery and it was strong enough to crank the engine over but it was so borderline that the computer was losing crank signal during the crank. I hadn't seen that before but apparently Sam had, he went right to the issue and saw the crank signal dropping out during cranking. The guy had a little fork lift battery or something like that in there.

 

 

If you hear the fuel pump and also tried spraying starting fluid in it and it still doesn't run it must be ignition.

I'd go for battery first, then cam or crank sensor if that doesn't help.

If you have a jump box around connect it up and turn it on and fire the truck with the battery and jump box, if it fires right up you know you have a weak battery. You could also boost it from another vehicle for a few minutes before cranking it, in other words jump start it. That would help tell you too.

 

The first 2 morning I did jump it with my Tahoe. Still a no fire.