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03-31-2009, 04:06 AM
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Hummer Veteran
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Join Date: Nov 2005
Location: Southern US
Posts: 75
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Rough Start
I am noticing that my 07 SUT seems to turn over a few times before catching. It cranks and sounds like it won't start, and then it starts. It only happens in the morning after it has sat overnight. Last time I was in for service, I mentioned it to the service folks. They said they put a meter on the starter and battery and that everything was ok.
Anyone else had this problem?
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03-31-2009, 04:18 AM
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Hummer Guru
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Join Date: Oct 2005
Location: Charlotte, NC
Posts: 2,767
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Re: Rough Start
Not sure if this is related but before I sold my H2, I noticed that when I started it, it would crank longer than normal before it would fire up.
I also noticed that fellow member, Tim, (TTKresurfacing) has the same problem.
Both of us had superchargers but it's almost like the fuel injectors are leaking and therefore don't have enough pressure to inject to fire it up..... or, better described if your fuel filter was dirty and it was taking an extra fuel cranks to get fuel to the engine. Not sure but end result would be the same.
I don't know what the cure was because I sold my old H2 and Tim's still does it. You may want to have your injectors cleaned/looked at.
HTH's,
Mark
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03-31-2009, 04:34 AM
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![[__--MUD--__]'s Avatar](image.php?u=8286&dateline=1300594796) |
Hummer Expert
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Join Date: Dec 2007
Posts: 705
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Re: Rough Start
Easy to test out... in the am instead of trying to crank it right over.. Just turn the key to the on position for 5 seconds or so, then crank to start. If it pops off right away, the fuel system is just leaking down.
Every car I have/had I've just always turned the key for a few seconds to prime the fuel. They start so much easier.
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04-04-2009, 02:50 AM
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Hummer Veteran
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Join Date: Mar 2009
Location: Ma.
Posts: 50
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Re: Rough Start
Mine did the same when I first installed the Supercharger....in my case it was some air in the fuel rail....I just turned the key and released the pressure from the fuel rail, I started it up and pressed and held it for about 5 seconds...be careful not to do this on a hot engine as releasing gas could hit the manifold/or header and cause a fire. BTW - release the fuel into a rag...this wont allow the fuel to spill.
Hope it helps - good luck!
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04-05-2009, 04:31 PM
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Hummer Veteran
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Join Date: Aug 2008
Posts: 48
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Re: Rough Start
Mine does the same thing. As someone already mentioned, it is most likely the fuel system leaking down.
Instead of turning key on for 5 seconds, turn it on and off twice or three times and then start the truck. If it starts right up, you have confirmed the problem. I dont know where the check valve is in these fuel systems, but most vehicles have a check valve of some sort to keep the lines primed with fuel.
Mine is 2005. I am surprised a 2007 is doing this.
Post back if you get it fixed and what they specifically replace.
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04-06-2009, 03:17 AM
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Hummer Veteran
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Join Date: Nov 2005
Location: Southern US
Posts: 75
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Re: Rough Start
Where the heck is the fuel filter on the 07's? I'm wondering if I shouldn't change that out, as I have about 28K on the truck now.
I used to change them about every 20k on my old Avalanche and on my Tahoe.
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04-06-2009, 03:42 PM
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Hummer Professional
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Join Date: Oct 2007
Posts: 267
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Re: Rough Start
Did someone say Fuel Pressure Regulator?
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