Slow cranking due to battery cable?

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DaveO9

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My 2009 Tahoe, 5.3, cranks slow, especially when cold. It's been that way since I've owned it, but that's only been about 2 months. I had the battery load tested - tested good and it's only 2 years old. Battery shows 12.3V with key and engine off. Engine running I see 14.7 or so at the alternator and about 14.3 at the battery. Seems like that could be enough voltage drop to cause a slow crank condition? I noticed my negative battery cable is looking pretty sketchy at the post terminal. Even if it's not causing the slow crank, I'm going to replace it. I don't have any other electrical anomalies, though.

Thoughts? Would the starter itself be going bad?

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Geotrash

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My 2009 Tahoe, 5.3, cranks slow, especially when cold. It's been that way since I've owned it, but that's only been about 2 months. I had the battery load tested - tested good and it's only 2 years old. Battery shows 12.3V with key and engine off. Engine running I see 14.7 or so at the alternator and about 14.3 at the battery. Seems like that could be enough voltage drop to cause a slow crank condition? I noticed my negative battery cable is looking pretty sketchy at the post terminal. Even if it's not causing the slow crank, I'm going to replace it. I don't have any other electrical anomalies, though.

Thoughts? Would the starter itself be going bad?

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That battery cable absolutely needs replacing. Might as well do "the big 3". Lots of posts on here about how to do it and which cables to buy. But if time and money are tight, replacing just the negative cable in your case will probably solve your woes.
 

Joseph Garcia

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While you are at it, check the grounds on the engine block and any other grounds in the engine well. A corroded ground is common on these trucks.
 

OR VietVet

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Yes, what has been said so far and the voltage drop is fine. IMO, do both cable assembles and read thru threads here and do the Big 3 asap, especially if live in a state with salt on the roads. If you want to have a little fun. Get a helper and crawl under the engine and measure the voltage at the starter now. Then do the cables replacement and measure again. Please report back here with results. Plus, if you can afford it, replace the starter since it is likely the original. I did mine, had no problems with it, because I knew eventually it would give me a problem when away from home. https://www.rockauto.com/en/moreinfo.php?pk=4394409&cc=1442911&pt=4152&jsn=927

Pay attention to all choices for the battery cables because Genuine GM cables have a few options.
 

Tonyv__

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I feel like this topic has came up a couple times this year alone. It seems the common culprit is the starter dying. I don’t wanna tell you to just throw money at your starter. But i experienced it this year too. Replaced my battery for no reason just to find out my starter was dying

My Yukon only had about 60k miles when it happened
 
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DaveO9

DaveO9

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Thanks for input, everyone. I'm assuming the "Big 3" are positive and negative batt cables plus the braided ground strap from engine to firewall on drivers side? I've looked at the connections for all of those and the only visible issue is the negative cable at the post (pics that I posted above). There's not a spec of corrosion on any of them. So I'm going to replace the negative cable first and see what that does. I'll replace the starter if I need to, but not without first trying the cables. I'm in SW Washington, bought the rig in Portland OR - neither state salts the roads so corrosion is not as big a problem as it is for other areas.

Here's the cable I'm purchasing, AC Delco.
 

OR VietVet

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Thankfully, yes, no salt on roads here in the Willamette Valley, Eugene, Or.




Many more info threads to be read.

Go to top right where it says, SEARCH with the little magifying glass, click on it and type in Big 3 Upgrade and hit enter and scroll.
 
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DaveO9

DaveO9

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Thankfully, yes, no salt on roads here in the Willamette Valley, Eugene, Or.




Many more info threads to be read.

Go to top right where it says, SEARCH with the little magifying glass, click on it and type in Big 3 Upgrade and hit enter and scroll.
Got it, thanks. I had no idea the "Big 3" mod was such a BIG deal for these trucks. I thought it was just a colloquial term amongst a small group here and an actual search wouldn't turn anything up. Guess I should have tried first! All over this site and every other forum dealing with these rigs.
 

Geotrash

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Got it, thanks. I had no idea the "Big 3" mod was such a BIG deal for these trucks. I thought it was just a colloquial term amongst a small group here and an actual search wouldn't turn anything up. Guess I should have tried first! All over this site and every other forum dealing with these rigs.
Geez, man. I even gave you the quotes around it for the search term! :p

But I'm also with the others here that your starter is likely nearing its end as well. It's easy to replace on these. Just gotta take the right front fender liner out and remove the heat shield from the exhaust manifold on that side. The starter is held in by 2 bolts from the bottom. Took me maybe an hour to do it on my '07. You gotta get in there anyway to replace the cable that runs to the starter, so it's as good a time as any to replace it.
 
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