Strange Starting Issue - Dealer Struggling to diagnose, Silverado in excellent condition

[Micah Page]

Hello, I am seeking feedback and ideas for a problem my truck is having.  Truck is in excellent condition and has been 100% reliable until this issue came up.  All regular maintenance is performed at the dealer.  Truck is pretty much a pavement princess - I don't drive it hard and I detail it often (looks new inside and out).  2017 Silverado, crew cab, Z71, All-Star Edition, 5.3, 6SP - 83K miles (Highway miles, I travel to ride dirt bikes recreationally, no towing ever.).  Here is the issue history that started about 6 months ago.  The battery died (normal) and I replaced with an O'Reilly's battery.  A couple months later the vehicle would sometimes not start when the key was turned all the way to the starting position.  The vehicle would start on the 2nd or 3rd attempt (turn key off and then back to start).  A couple times I let the vehicle sit and tried again and it started.  All the power/electrical comes on when the key is turned to the on position. When the key is turned to the start position, there is nothing (the starter does not engage).  O'Reilly's warrantied the battery and sold me a more expensive one ($40) and said it was a better battery for the truck because of the remote starter.  Btw, the battery is never dead.  There is always power to turn on electronics, lights, and start the vehicle if the starter engages.  Anyhow, months later the problem still happens (sometimes daily and sometimes not for several days), except once it threw the vehicle into limp mode.  They said there was a throttle body issue and they remapped the CPU.  I got the truck back and week later I could feel my stability control working on the front right wheel while I was crusing at 35MPH.  The stability control like came on and then the engine light started flashing.  The dealer said there was a cylinder misfire (#5),a bad spark plug and this caused the stability control issue.  They also replaced the ignition coil.  I get the vehicle back and have the same problem the next morning (turn the vehicle to start, starter does not engage, turn off, turn back on vehicle starts...can be on the 2nd or 3rd attempt).  The start up sound sounds a little weaker than normal when the issue is happening, as during normal starting the 5.3 comes to life very strong sounding when the issue is not happening.  That said I have had the vehicle at the dealer for a combined 4 days and paid $200 for the extended warranty charges.  My next step is to have a meeting with the service advisor and service manager.  Anyone have any ideas I can present to the dealer?   (Why would the starter not engage when the key is turned to the start position?) Thank you.  

Edited September 6, 2021 by Micah Page

[Z45]

The battery makes me think that somehow the problem is related to it.  Did you install the battery?  Maybe you inadvertently did something when doing so. You also could have a battery cable problem. Even though they may appear in good condition there may be hidden corrosion inside.  There have been reports of persons having weird starting issues related to bad cables, their might even be a service bulletin on that?

Edited September 7, 2021 by elcamino

[Micah Page]

Thank you for your reply and the suggestions.  O'Reilly's installed the battery.   All this started after the battery was swapped.  I'm going to discuss the cables and any potential services bulletins with the dealer.  That seems like a good thing to look into.  Thank you again.

[savagebob]

. The simple basic things to do that precede simple voltmeter  checks are to hold the key in the full start position whenever it will not crank (no starter rotation) and wiggle the shift lever in park (even when locked in park). If the engine starts cranking when wiggling the shifter, then the issue lies in the trans selector circuit. Try it in neutral when it is acting up and see if that cures it.

Ignition switches also can cause quite a few intermittent no crank problems.

 

Proper electrical diagnosis is a logical progression and doesn't care about any assumptions about previous repairs. Those will only cloud the logical diagnosis. Cranking problems can be diagnosed quickly if the problem is present when diagnosing.

Voltage drop tests and the wire wiggle test can help to find intermittent issues. Sounds like you need a more technical technician.

Edited September 8, 2021 by savagebob
grammar correction

[savagebob]

If a couple of months passed after changing the battery, and there were no starting problems in that 2 month period, then all bets are off as to what the problem could be. Like I stated above, the diagnosis is not difficult if carried out in a logical progression, with simple electrical checks with only a voltmeter and a couple of jumper wires.

[Micah Page]

Thank you for the reply.  It is very helpful.  I am going to take it to a different dealer...there are several in this area.

Edited September 8, 2021 by Micah Page

[diyer2]

10 hours ago, savagebob said:

If a couple of months passed after changing the battery, and there were no starting problems in that 2 month period, then all bets are off as to what the problem could be. Like I stated above, the diagnosis is not difficult if carried out in a logical progression, with simple electrical checks with only a voltmeter and a couple of jumper wires.

Agree

The problem is finding the tech capable or willing to do it. 

[Micah Page]

Summary from the dealer:  There is corrosion on the negative battery cable.  He implied that this could have caused the starter motor to fail.  Replacing the negative battery cable, starter motor, and installing new spark plugs (truck has 84K miles...this was my choice).  So that should be it.   Thank you for the replies!  I appreciate the support from the community.

Edited September 15, 2021 by Micah Page