Engine Cranks But Wont Start

In this video we encounter a scenario where the engine cranks over but wont start. the subject vehicle is a 2007 Chevy TrailBlazer SS equipped with the 6.0L engine. we discuss common causes and dig into diagnosing this hidden problem. The discovery of multiple fault codes and some erroneous data PIDs lead us on a trail for a deeper cause. Watch this video for all the twists and turns and the anticipation of finding the cause. Will it be a happy ending? Lets find out!

NOTE: I omitted an additional sensor in the problem circuit while filming. The coolant fan speed sensor is also in the effected circuit however was not the cause of this particular issue.

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[freddy]

I like how you put videos out to help the do it yourself'er and also cut a break on the customers bringing you the business. It goes a long way when your honest and considerate. Job well done and the professionalism shows. Thanks for the video.

[hexxleon]

Sir what I'm about to say is something I dont usually say to a mechanic. Thank you. Even though you've done nothing for me you just did more than any of the "mechanics" I've paid alot of money combined. It's so sad that your the last one left from an extinct species. A good honest mechanic

[stuzman]

Good job Tim on finding the culprit for missing 5V. And that was pretty sneaky in finding away around those long hours in replacing that crank sensor. Well done!

[aaronshensky]

Nice work! Great video, good to know. I have a 06 trailblazer ss 6.0 awd that would stall out/cut off when it reached operating temp (whenever under the hood it got warm/hot) had me baffled for couple days. Narrowed it down to weak circuit in underhood fuse block whenever car got warm/hot. It wouldn't start up until cooled down. Replaced Under hood fuse block and no more issues. 1yr later still good. Thanks for your video. I'll keep note of this video next time. I plan on keeping my 06 tbss for years. Enjoy your videos and knowledge. Keep it up. Thumbs up !

[July-A]

It turned out to be the cam shaft position sensor. Replaced it and it starts fine now. It was giving eratic signals apparently. Online materials say that that sensor is for fine tuning and the car will still run with a faulty sensor, and that the Crankshat position sensor is the one to look out for if the car won't even start, but mine looks to be very sensitive, hence no start, whichever sensor may be faulty, even if was the one that monitors if my kids have snotty noses in the car.
All the best in your garage and informative videos!

[OneAuto]

Nice Job tracking that 5V Ref down, shame it wasn't the throttle pedal. That crank sensor was well & truly buried!

[davidd]

It's always good to learn how mechanics learn work arounds to make their jobs easier. Work smarter not harder.

[Badgertronix]

that's a lot of codes. Nice work getting it fixed up

[mostlymoparih]

Ya gotta pull the starter to replace the sensor, dang the GM engineers didn't use the 7 p's there. Another won bites the dust. good vid pal.

[X_PackWolf_X]

I got a trailblazer that wont start sometimes but when it starts its a rough idle and stalls in like 10sec after start up i have no codes any suggestions? has new fuel pump spark plugs and a lot more thats new on it

[wyattoneable]

Great job explaining the process and the camera angles were lots of fun too.

[wysetech]

You're a smart guy. Nice job Tim.

[fieldsofomagh]

!First time seeing key hole surgery on a trailblazer. Great logic thinking with the diagnosis of the 5 V ref theory. All systems good to go in Anchorage Alaska !

[ManicMechanic]

Awesome diagnostics.
The Doctor is in!

[BigDog]

Easier to say which check engine codes were not set lol. Good video Tim.

[DanWebster]

Another successful repair you on a roll! High tech stuff man.

[SierraOne]

I'd love to see how you use the "mechanical arms" to install. Tough camera angle I gotta believe. Another amazing shortcut, way cool!!

Oh and Thanks for the info and video.

[July-A]

For some reason I cannot reply to your comment directly. As the matter has gotten worse, there is no signal to the injectors. I'll see if of the crank position sensors is the culprit. Perhaps not triggering ECU to give signal to the injectors if how the sustem works. All the best to you, Car Doctor!

[lfrw]

I have the exact same trailblazer thank you very much for the video keep doing a good job 👏👍

[haywardsautomotive]

Nice 5V Ref diagnosis Tim. Find the one pulling it low but that was about the cheapest out of all of them including the coolant fan speed sensor. Trailblazer SS with the 6.0 I have the Silverado SS with 6.0L...it's got some power. 4 hrs to pull a starter and change the CKP sensor is hilarious b/c it takes about 1 hr. total time. Nice video Tim!!