I have a 2000 Silverado, 5.3/4l60e with 190k. The last few mornings it's been down to 0 degrees in the morning and my truck won't start. It turns over but won't fire. But later in the day after the weather warms up, it'll start no problem. Theres no relevant codes and I've tried a shot of starting fluid to see if it's getting fuel. Didn't even sputter. I cant think of anything electrical that would be affected by cold. Any ideas?

 

Hard to say... cranking speed ok when below zero? How much warmer is it when it'll start? Maybe it just needs more starting fluid. The colder it is the more fuel an engine will require, especially to start. Fuel doesn't vaporize in low temps like it does in warmer temps making it much harder to ignite. Try more ether directly into the throttle body.

 

Once it warms up to 20 or so it'll start.

 

Could it be VATS acting up?

 

Check it for no spark when cold and I use a timing light while cranking to see if I'm getting spark. Use a NOID light to see if the injectors are firing during cranking.

If you are getting the starting fluid sprayed into the intake right at the throttle body and it does not start, I predict that its a spark problem. They don't call that stuff "Explosion In A Can" without good reason.

Rick