Convenient start feature moody

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Convenient start feature moody

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Chevrolet >> Chevy Trucks, Vans & SUV's >> Tahoe >> Convenient start feature moody

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Convenient start feature moody - 5/12/2008 5:32:47 PM

bimmerborn

Posts: 94
Joined: 10/28/2007
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2007 Tahoe has a "Convenient Start" feature, meaning one needs to turn the key to the start position just enough for giving a start signal to the computer to start the engine. Then the computer cranks the starter as long as required for the engine to start. This is regardless of one holding the key in start position or not.
On my Tahoe this "Convenient Start" feature does not work all the time. Specially (I noticed) when the fuel level is too low. In this case, when giving the signal to the computer, the engine cranks one time and then stops. I am not sure if this is done by design or it is a bug. Your feedback is appreciated.

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RE: Convenient start feature moody - 5/12/2008 9:01:03 PM

73shark

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I use the "twist & release" start and it works even with the "low fuel" lite on.

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RE: Convenient start feature moody - 5/13/2008 2:45:56 PM

ZX1100F1

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Joined: 8/1/2006
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Quote from GM TSB:
"Some customers may comment that the engine starter will continue to run after the key is released.
For the 2003 through 2008 model years, the Powertrain Control Module (PCM) or Engine Control Module (ECM) controls the starter relay based on input from the key switch. When the ignition switch is held in the start position for 0.4 seconds, the PCM/ECM start timer is activated. Once the start timer is activated, the PCM/ECM will continue to crank the starter until either the engine starts or a no start time limit is reached.
Occasionally, the fuel pump module will take one or two seconds to build fuel pressure. Often this will occur after the vehicle sits overnight. During some vehicle starts, the customer may release the ignition switch key before the engine actually starts. When this occurs, the engine will then continue to crank until the engine starts or the no start time limit is reached. This is a normal condition and no repairs should be attempted for this condition."

< Message edited by ZX1100F1 -- 5/13/2008 2:46:33 PM >

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RE: Convenient start feature moody - 5/13/2008 2:54:12 PM

BMoTahoe

Posts: 102
Joined: 3/24/2008
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I'll just continue to use the "turn the key" or remote start to get my Hoe running. That convenience start feature is something I've never heard of.

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RE: Convenient start feature moody - 5/13/2008 3:54:40 PM

bimmerborn

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Joined: 10/28/2007
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Folks, thank you for feedback. I am not sure if this is an issue of any sort. In fact I think this is another feature designed by smart GM Engineers. When I think about it then it makes sense. So the PCM (or ECM) disables "Convenient Start" feature when the fuel level is low; Therefore the Engine does not crank for long time in the case of insuffecient fuel to start the car. In other words ECM puts driver in charge of cranking time. Smart!
This has happened to me 2-3 times when my "low-fuel" light was on. It did not happen after I filled up the tank. I let the light come on next time and try again. I will let you know. Thank you again.

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RE: Convenient start feature moody - 5/13/2008 6:14:27 PM

ZX1100F1

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Joined: 8/1/2006
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Low fuel should have no effect on the operation of the Computer-Controlled Cranking System, my best guess is that you failed to hold the key over to the START possition for the required .4 seconds and coincidently happened to be low on fuel.

This system also prevents the starter from engaging if the motor is already running or remaining engaged for more than 15 seconds and was implemented to protect the starter motor not necessarily as a convenience device.

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RE: Convenient start feature moody - 5/14/2008 6:32:36 AM

davemec

Posts: 243
Joined: 7/19/2006
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You also could have a bad fuel pump. I had similar starting problems, and the dealer found that the fuel pump was bad. They replaced it and I haven't had problems since.

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RE: Convenient start feature moody - 5/14/2008 7:42:45 AM

bimmerborn

Posts: 94
Joined: 10/28/2007
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Correct. I am sure I never hold the key in start position for .4 seconds or more. I will keep an eye on the fuel pump. Thank you.

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RE: Convenient start feature moody - 7/4/2008 10:58:45 AM

bimmerborn

Posts: 94
Joined: 10/28/2007
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With all respect to all friend and good members of this forum:
I will insist on my posts in this thread. From the original post time I have tried many many times. Here is what I have observed.
- When the fuel level is fine (fine means the low-fuel warning light is off) the convenient start feature works properly. Does not matter how long of a signal you give the starter. My length of the signal is just like when I push a radio station button.
- When the fuel level is low and the warning light is on I have noticed there are 2 cases. In the first case the DIC is still able to show you how many more miles you can travel. In this case the convenient start feature works fine. In the second case, the DIC also displays "Low Fuel Range" and here is where the convenient start feature disables. My conclusion, and it is only my opinion, is this is not a flaw. The fact that convenient start feature does not work at very low fuel levels is a smart design by good engineers in GM. This prevents extra cranking of the engine if there is no fuel. Thank you again GM.

Happy 4th folks.

(in reply to bimmerborn)

Post #: 9