Crank but will not start

Hello,

There are a couple of ways to go about this. Basically an engine needs three thing to run. 1) Fuel. 2) Ignition source (spark). 3) Compression. Since you can't tell if the fuel pump is coming on or not, and I like to start with this one anyway, let's see if you are getting spark. I have included down below a couple of links for you to go to.

https://www.2carpros.com/articles/how-to-test-an-ignition-system
https://www.2carpros.com/articles/car-cranks-but-wont-start

Please go through these guides and get back to us with what find out. We can go from there.

Thanks,
Alex
2CarPros

Hey, fuel pump is working, verified by literally crawling underneath and hearing it and unhooking from under hood, has fuel there to!
Still when you turn the key, it acts like it’s going to then nope notta.. plugs have spark ):
Fuses and relays look good.
Can the cam sensors cause this much issue? Crank sensor? Those was next on the list ): has decent compression. I honestly don’t think it’s a timing chain, issue. Called gm they verified my vin was in the good ones with no recalls. I’m starting to get annoyed!

Hello again,

Okay, Let's try these Technical Service Bulletin's (TSB) first. Then I have a factory troubleshooting guide with a couple of tests that probably wouldn't have been thought about. I have them all listed in the diagrams down below. Please go through them and get back to us with what you find out.

Thanks,
Alex
2CarPros

There isn’t any codes showing at all, just an check engine light, but it won’t fully start to check for one. It acts like it, then nothing.

Hello again,

Okay. Can you get a can of starting fluid and give it a couple of shots by where the air comes in at the breather. Don't over do it. Have an assistant crank the engine and see if will start for a couple of seconds that way please. Get back to us with what you find out.

Thanks,
Alex
2CarPros

Hey that seems to be good. Took out cam sensors 1 seems to be completely dead. Others have around 200 on meter.

It won’t start. Acts like it’s going to then nothing.

Hello again,

Did you see if would start with a shot or two of starting fluid for a second or two?

Thanks,
Alex
2CarPros

No it just acted like it wanted to start. But then nothing.

Hello again,

Normally hear I would say that it is time to test the Crankshaft Position Sensor(CKP) because it sounds to me like you are not getting spark, but you mentioned something about your Camshaft Position Sensor being dead earlier so let's test those again first. I have included a factory test for these in the diagrams below. Please go through the tests and get back to us with what you find out. If one or more have failed then they will need to be replaced.

Thanks,
Alex
2CarPros

Thank you! I will get back with you soon. I will try and video it so you can hear it.

A video really helps. :)

Okay, second full day of this ! Sorry I haven’t replied sooner the baby had her birthday yesterday. Okay, a few days ago replaced cam position sensors. still wouldn’t run. Then when we went out to try it again Monday the battery was dead so we put it on charge. took it hooked it back in to the GMC came inside to do the party. Went out it had leaked. I took it to advance and they said it charges and was a little higher then should be okay. so they switched it. today we put it in all it did was click! Okay plugged it up it’s dead? Like barley any charge. can’t even see if the crank sensor fixed it! Can it be a bad battery or what? Can the car be doing this? could it be why it won’t run? Like what’s going on?

Hello again,

This is without question parasitic draw. I have included a link for you to go to down below.

https://www.2carpros.com/articles/car-battery-dead-overnight

Please go through it and get back to us with what you find out.

Thanks,
Alex
2CarPros

So did they give you a new battery? Check the positive battery cable as well it may need to be replaced.

Here is a guide to load test the battery:

https://www.2carpros.com/articles/car-battery-load-test

Please let us know what you find. We are interested to see what it is.

Sorry we had to do the starter. Now this all it does.

Hello,

That sounds like the Bendix gear comes out and tries to turn the flywheel but the battery isn't strong enough to turn the starter motor so the Bendix retracts. Can you guys take a multi-meter and tell me the voltage of the battery, please.

Thanks,
Alex
2CarPros

Here is a guide to help:

https://www.2carpros.com/articles/car-battery-load-test

Please run down this guide and report back.

It shows good voltage possibly overlooked something with wires you suggested while back.

Hello again,

Okay, Then can you please check the connections at the battery? Make sure they are clean, corrosion free, tight, and have good metal to metal contact. Follow the wire from the battery(+) to the starter making sure it is not damaged and check the connections on the starter please. I have included information on the starter connections in the diagrams down below, Please check these connections out and get back to us with what you find out please.

Thanks,
Alex
2CarPros

I am sorry I haven’t been able to get on to now, cables are good. It won’t do anything more now. Tried to turn manually just sounded like chain jumping. I red I shouldn’t have done that. After the fact.

Hello,

Okay, when you turned the engine over by hand did you feel any unusual resistance? There should be a little but the engine should smoothly turn and you should hear the valves opening and closing. How did it turn out?

Thanks,
Alex
2CarPros

I have a 2007 Acadia that has a similar cranks but won't start issue.
It started to idle rough and after disconnecting various connectors and reconnecting them to see the effect, I discovered the root issue was a shorted cam position actuator wire pair near the connector. Unfortunately now the car just cranks but won't start. It has fuel to the fuel rail and spark. While using starting fluid, it blew a flame out of the intake. The only way that I figure it can do that is if a valve is open while it's firing a spark plug, which would mean that the spark timing is way off.
I've since changed the crank position sensor, tested all the fuel injectors to be good, and replaced the camshaft position sensors. I'm thinking that the electrical short may have fried the ECM, I've also bought and replaced that.

Does anyone have any suggestions? A ECM Pinout would also help so that I could verify wiring (like crankshaft position back to the ECM)
Please help..
Thanks

Hello,

In the diagrams down below I have included the information that you requested, an Engine Control Module(ECM) Pinout with callout with wire colors. Please go through this Pinout chart and get back to us with how things turn out, please.

Thanks,
Alex
2CarPros