Replaced headlight bulbs and now car will not start

JEFFREY BOONE

MEMBER
2005 CADILLAC CTS
6 CYL
2WD
AUTOMATIC
118,000 MILES

Replaced the headlight bulbs in my car. Did not disconnect the battery, put the bumper back on. All lights and systems work however when I crank it it turns over and almost starts but will not run. Symptoms similar to being out of gas. Drove fine the night before the headlight change. Shows 1/4 tank of gas. I even added a gallon to be sure. Where do I start trouble shooting?

1 Reply

KASEKENNY

MECHANIC
18,907 POSTS

We need to start by go back over what you removed and see if there is any chance something is still unhooked.

Then scan for codes. Hopefully there is a code that will give us something to go on.

If there are no codes then we will have to start eliminating things. The first thing is to spray starter fluid in the intake and see if the engine fires. If not, then we need to remove a spark plug and connect it back to the ignition system and hold it against the block to see if it sparks.

The purpose of this, is you need three things to fire an engine. Spark at the right time, fuel, and compression. We can assume that the compression is okay since it was just running and nothing dramatic seemed to happen. However, we may have to come back to this if nothing else pans out.

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

https://www.2carpros.com/articles/engine-cranks-excessively-before-starting