'11 starting issues

nate1dawgg · November 23, 2015

So I've got a bunch of people stumped with this one. Hopefully someone here has some suggestions.

My '11 1500 LTZ has interesting issues starting when it's cold out and has been sitting for a while (6+ hours). When I go to start it, I'll turn the key, and it will crank for a few seconds and then finally catch and start. While it's cranking, I'm not holding the key in the start position, I actually don't even touch the key.

So first thought, battery. Less than a year old battery, but I figured I'd check. Good battery, no problems there. So I took it to the shop, they looked at it and found all 8 spark plugs bad and bad injectors. They replaced all those, called and said it started right up. I picked it up and let it sit over Friday night. Went to start it up Sat. morning and the same issues.

Went to start it this morning and same issue. Talked to the shop, they're going to take a look at it again this afternoon, but I'm looking for outside help.

Here's a link to a video of what it's sounding like - video.

Any thoughts are appreciated.

oldmann · November 23, 2015

These truck have an auto crank feature. What you describe sounds like it is working like it should.

waumo1 · November 23, 2015

Checked fuel rail pressure?

nate1dawgg · November 23, 2015

These truck have an auto crank feature. What you describe sounds like it is working like it should.

So it cranks longer than normal, and only when it's been sitting in the cold for a longer period of time. When I start it in the morning (a longer crank) and then turn it off and turn it back on, the second time i turn it on, it starts up immediately, no long cranking. And this started happening last year, prior to that, it always started right away.

Checked fuel rail pressure?

I'm not sure what the shop has checked, like I said, they thought they fixed it before, but no so much. I'll ask them when I'm in today.

sahls01gmc · November 23, 2015

If it still starts on the auto-crank, you're fine. Cold weather can play a factor into that. Turn the truck to "on" for a few seconds, then to start. Check condition of the fuel pump and filter.

nate1dawgg · December 7, 2015

So just a follow up to this, apparently there is something out there that addresses this. #PIP4792D. Had the shop look at the alcohol content and sure enough it was off. Got it calibrated to the right specs and so far haven't had any other problems.

Subject: Cold Extended Crank - Rough Running - And/Or SES Light With DTCs P0172 And/Or P0175 - Check Fuel Alcohol Content

Models: 2010-2011 Cadillac Escalade 2009-2011 Chevrolet Avalanche, Express, Silverado, Suburban, Tahoe 2009-2011 GMC Savana, Sierra, Yukon with E85 Compatible V8 Engine (RPO Code L20, L77, L94, L9H, LC9, LH9, LMF, or LMG)
This PI was superseded to update model years. Please discard PIP4792C.

The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
On rare occasions, an extended crank on cold start, brief rough running on cold start, black exhaust color, and/or SES light may be experienced.

If a SES light is experienced, DTC P0172 and/or P0175 may be stored. If engine performance symptoms are experienced, they will generally diminish within 1 minute of startup.

This may be a result of the ECM learning the fuel ethanol content incorrectly even though the customer does not use E85 fuel.