Car has just recently stalled out randomly

Tiny
DAKPLUMB0329
  • MEMBER
  • 2006 PONTIAC G6
  • 3.6L
  • V6
  • FWD
  • AUTOMATIC
  • 144,000 MILES
Just recently my car had stalled out like I had no gas in it getting on highway. Checked all fluids and gas and everything was normal. Started it up about an hour later and made it maybe two miles and then same thing. Would make it to about sixty mph and then just shut down. Have had the security light randomly pop up on dashboard periodically but it has been doing that for about seven months. Had to get it towed back to wife's grandma's house. When I went to plug in diagnostic reader it is giving me nothing because no engine light is on. Car does sound like there is no oil but I have checked and it is fine. What could be the problem?
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Tuesday, June 20th, 2017 AT 11:24 PM

7 Replies

Tiny
CARADIODOC
  • EXPERT
Whether or not there are diagnostic fault codes has nothing to do with the check engine light being on. The engine computer can detect over 2,000 defects. About half of them refer to things that could adversely affect emissions. Those are the codes that turn the check engine light on.

Intermittent stalling is commonly caused by a crankshaft position sensor or camshaft position sensor that is failing by becoming heat-sensitive. The clue is they will work again after cooling down for about an hour. When the engine Will not run with a failed sensor, it cannot pollute excessively, so it is likely the check engine light Will not turn on.

Also, be aware that on some models, a fault code Will not set for a failed cam or crank sensor just from cranking the engine. That can incorrectly make you think those sensors are okay. Instead, you need to look at them with a scanner to see if their signals are arriving at the engine computer.
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Tuesday, June 20th, 2017 AT 11:45 PM
Tiny
DAKPLUMB0329
  • MEMBER
Yes it does turn on after a certain length of time. But it is making noses like there's no oil but al fluids are correct. Could that be the crankshaft not properly turning
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Thursday, June 22nd, 2017 AT 11:52 AM
Tiny
CARADIODOC
  • EXPERT
Have you used a scanner to see if the sensor signals are arriving at the computer?

I am not sure what kind of noise you are hearing. Part of what you are describing suggests the flex plate is broken. The starter would sound weird. It would spin too fast and steady. The crankshaft would not rotate during cranking.
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Thursday, June 22nd, 2017 AT 4:24 PM
Tiny
DAKPLUMB0329
  • MEMBER
I have just used a code scanner like I mentioned before. Do I have to take it to a garage to have that tested or is there a way I can test it myself. My Gpa was a mechanic and left me and my father a lot of tools. Is there a certain way to test it.
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Friday, June 23rd, 2017 AT 4:52 PM
Tiny
CARADIODOC
  • EXPERT
Reading diagnostic fault codes is just a tiny percentage of what scanners do. One of their main uses is viewing the live data the computers see and act on. That is what we need to do when there are no fault codes to get us started. Even when there are fault codes, those only indicate the circuit or system that has the problem. I'd equate your code reader to your family physician, and your body to all the computers in your car. You can read fault codes, but only in the Engine Computer. Your physician can figure out which part of you has the problem, but then he has to send you to the specialist. The fault code gets you to the circuit, but you may need the scanner, (the specialist), to view the incoming sensor data, command outputs to activate, and watch what happens when you force defective conditions to occur.

When the people at auto parts stores read fault codes for you, they almost always are using a simple code reader like you are, and they only read codes in the Engine Computer. Mechanics use scanners that can access all the computers on the vehicle, and provide a lot more information, but they also cost about 100 times as much as a code reader. To make it even more insulting, some of the more popular scanners "only" cost around $4000.00, but the company charges $1000.00 per year for the updates, and you can't skip any years. That's why shops have to charge for using them.

You've reached the mechanic's dilemma where there are no fault codes to get us started. And remember, even if you did find a fault code, they never say to replace parts or that one is bad. Even when a part is referenced in a code, that part is actually the cause of that code about half of the time. They just get us into the circuit with the problem. With no code to go on, you have to use the scanner to figure out what looks wrong.

I should mention too that sensors develop a signal voltage, and to use a common 5-volt sensor for my sad example, its acceptable range of signal voltage would typically be 0.5 to 4.5 volts. The problem is if it develops the wrong voltage, the computer will act on it, as long as it stays within that acceptable range. It has to go below 0.5 volt or above 4.5 volts to set a code. We have to be smart enough to know that 3.0 volts is an acceptable voltage, but it's the wrong voltage if it doesn't agree with the condition. For example, at idle, a throttle position sensor will read near 0.5 volts. It had better not be reading 4.2 volts if we aren't pushing the accelerator pedal.

The position sensors I described earlier develop a different type of signal. Voltage has nothing to do with what the computer reacts to. Those are timing pulses, and voltage is not that important. There is no easy way to observe those pulses, and if we did, there would be no way to figure out if they're showing up at the right time. The computer does that, then it talks back and forth with the scanner so it can display that information.
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Friday, June 23rd, 2017 AT 6:08 PM
Tiny
DAKPLUMB0329
  • MEMBER
I comprehend everything ur telling me too the fullest. I'm aware of the fact that this is not a common problem and really value the time that u have spent talking with me. Back of my head told me I would have to take it somewhere for professional diagnosis. I'm service plumber so I can relate. I will try and find a mechanic with good rep where I am currently at. I appreciate and respect the time u have giving me. Thanks again man. When I find out the problem I will email u so u can add it to ur arsenal. Thanks again
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Sunday, June 25th, 2017 AT 10:31 PM
Tiny
KEN
  • ADMIN
Please let us know what happens.

Cheers, Ken
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Wednesday, June 28th, 2017 AT 5:14 PM

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