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I'm the owner of a 2007 G6 GT 3.5L convertible, having the issue that my car won't start reliably. It sometimes starts and runs but after sitting for a short time after it has been turned off it refuses to start. The starter clicks and it won't even crank. The battery is new and the voltage reads right, the alternator is also new. I literally just installed the new starter motor, while I was under there I noticed that the oil sensor next to the oil filter had developed a slow leak. But mindful of this I cleaned the electrical connectors leading to the new starter. It's not the anti theft, and it has a remote start that works fine so long as the car is having a good day. The engine also makes a slight whistle past 2k rpm but I think it is just a minor exhaust leak. Bad ground? IDK what to do. Its left me stranded more and more since I bought it in march.


TLDR: new starter/battery/alternator, intermittently starts sometimes
 

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If you have access to battery jumper leads you could use one to make a connection between the battery ground and engine block when the car is clicking and not starting. Also worth checking if there are any OBD Scan codes.
 

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If you have access to battery jumper leads you could use one to make a connection between the battery ground and engine block when the car is clicking and not starting. Also worth checking if there are any OBD Scan codes.
Hey Boomer, thanks for the response. However the main grounding wire itself isn't the issue(I took it off and cleaned it with sandpaper). Could it possibly be another ground somewhere else in the car, maybe something close to the cars computer?
 

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The grounds have been known to corrode internally, so cleaning the end may not be enough. There are also grounds to the chassis, transmission etc. You mention the starter solenoid is clicking, which would indicate that it is getting the signal to start / engage the starter. I would have thought the only other missing ingredient at that point would be power from positive and ground. Could be wrong though.
 

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When it cranks but won't fire listen for the fuel to run or better yet check with a fuel pressure gauge. That checks off if the fuel pump is running or not. To check the starter, jump the starter relay. If the starter cranks the ground is good and so is the starter.
 

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When it cranks but won't fire listen for the fuel to run or better yet check with a fuel pressure gauge. That checks off if the fuel pump is running or not. To check the starter, jump the starter relay. If the starter cranks the ground is good and so is the starter.
It's not as fuel issue, the fuel pump is working normally, the thing won't crank, the starter motor clicks.
 

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I'm the owner of a 2007 G6 GT 3.5L convertible, having the issue that my car won't start reliably. It sometimes starts and runs but after sitting for a short time after it has been turned off it refuses to start. The starter clicks and it won't even crank. The battery is new and the voltage reads right, the alternator is also new. I literally just installed the new starter motor, while I was under there I noticed that the oil sensor next to the oil filter had developed a slow leak. But mindful of this I cleaned the electrical connectors leading to the new starter. It's not the anti theft, and it has a remote start that works fine so long as the car is having a good day. The engine also makes a slight whistle past 2k rpm but I think it is just a minor exhaust leak. Bad ground? IDK what to do. Its left me stranded more and more since I bought it in march.


TLDR: new starter/battery/alternator, intermittently starts sometimes
I had the same problem with not starting. I took it to an auto electric shop. They said the fuse box under the hood was not grounded. They replaced it 6 years ago and it has started ever since. The whistle sound might be the weep hole in the exhaust pipe. My GTP makes that sound all the time. The weep hole is for moisture release but it makes a whistle sound when exhaust goes through the weep hole.
 

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I'm the owner of a 2007 G6 GT 3.5L convertible, having the issue that my car won't start reliably. It sometimes starts and runs but after sitting for a short time after it has been turned off it refuses to start. The starter clicks and it won't even crank. The battery is new and the voltage reads right, the alternator is also new. I literally just installed the new starter motor, while I was under there I noticed that the oil sensor next to the oil filter had developed a slow leak. But mindful of this I cleaned the electrical connectors leading to the new starter. It's not the anti theft, and it has a remote start that works fine so long as the car is having a good day. The engine also makes a slight whistle past 2k rpm but I think it is just a minor exhaust leak. Bad ground? IDK what to do. Its left me stranded more and more since I bought it in march.


TLDR: new starter/battery/alternator, intermittently starts sometimes
Someone told me a valve cover leaking onto it might cause this.
 

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Bunch of guesswork here...

Looking at the schematic - link below, There is a Run/Crank Relay Coil Control in the BCM. It feeds the Run Crank Relay 32 in the Underhood Fuse Block, which in turn feeds the Start Relay 31 in the Underhood Fuse Block, which in turn feeds the Starter Solenoid on the Starter.

So Relays 31 and 32 are in the Underhood Fuse Block. I think they are easily accessible. You may be able to feel them click / or not.

The Run Crank Relay 32 also has a Power Distribution Schematic that has an additional wire - guessing that might come from the key position?

Run/Crank Relay Coil Control in the BCM – guessing that Input wire could come from the Clutch Pedal or Auto Trans PRND position? (Is that still called a neutral safety switch these days?) These items get a lot of daily physical cycling. Since the problem is intermittent.... Possibly you could manipulate them when the problem arises and see if that makes it go! That would be an easy test before grabbing any tools.
Just Sayin'

Schematic Diagram https://www.g6ownersclub.com/attachments/2007_g6_ign_lz4-png.13819/
 

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My issue is the position sensor for checking that the transmission is honestly in park. Sometimes it registers, sometimes it does not. It's a $150 part so play around with the shifter and place your foot on the break and wiggle around in neutral to see if you can get it to start... Oh, and it will only make 1 little electrical click that sounds like it is in the starter when the computer doesn't believe you are in park or neutral. Even when you are.
 

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I'm the owner of a 2007 G6 GT 3.5L convertible, having the issue that my car won't start reliably. It sometimes starts and runs but after sitting for a short time after it has been turned off it refuses to start. The starter clicks and it won't even crank. The battery is new and the voltage reads right, the alternator is also new. I literally just installed the new starter motor, while I was under there I noticed that the oil sensor next to the oil filter had developed a slow leak. But mindful of this I cleaned the electrical connectors leading to the new starter. It's not the anti theft, and it has a remote start that works fine so long as the car is having a good day. The engine also makes a slight whistle past 2k rpm but I think it is just a minor exhaust leak. Bad ground? IDK what to do. Its left me stranded more and more since I bought it in march. TLDR: new starter/battery/alternator, intermittently starts sometimes
I had issues with it not starting when the vehicle or outside temperatures were hot. Took it to a mechanic to diagnose and turned out to be the fuse box, the pin wasn’t grounding when the vehicle was warm
 

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How about your starter relay? There is also a group on top of the transmission . Scanner Danner from YouTube has a video on it. Bad ground on a g6 . Worth the time to check it.
Sorry for the late response hope you had a good turkey day. The relay was fine as I replaced it and still had the issue. The problem was within the fuse box the pins weren’t being grounded when hot. For a while I thought it was the white wire that goes to the top of the transmission (think it’s for the neutral safety switch) I took that off and required it then it worked, took it off and it didn’t. But I guess it was just coolingdown and playing with me.
 

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Sorry for the late response hope you had a good turkey day. The relay was fine as I replaced it and still had the issue. The problem was within the fuse box the pins weren’t being grounded when hot. For a while I thought it was the white wire that goes to the top of the transmission (think it’s for the neutral safety switch) I took that off and required it then it worked, took it off and it didn’t. But I guess it was just coolingdown and playing with me.
Re-wired*
 
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