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3.0 Duramax won’t fire

170K views 697 replies 178 participants last post by  Codyb209 
#1 ·
Anyone ever experience trying to start a 3.0 Duramax and it won’t fire? Starter engages and cranks engine but will not fire and start.
 
#7 ·
That’s what happened the first time, wouldn’t start first try and then it did start. That was last week the day after I purchased the truck. Then day before yesterday it wouldn’t start on multiple attempts but an hour later when the tow truck showed up it started. Good thing I guess because tow truck driver had no idea how to put it in neutral without the engine running. Drove to dealer and now waiting to hear what they found.
 
#8 ·
Had this happen twice now, last time was just this afternoon. Went to start and the engine keeps spinning over but no start. Event probably lasts for 10-15 seconds. Nothing you can do but let it crank until it quits spinning. Next push of the button, it fires up like nothings wrong.

Truck has 3,000 miles, no clue what is going on.
 
#9 ·
I wonder if the computer stores the reason for unsuccessful start attempts?
Certainly sounds like computer is looking for a signal it's not getting. Bad or weak or misadjusted sensor or poor harness connection somewhere.
 
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#12 ·
This also happened to me once last week. The truck had less than 500 miles on it. I don't know if I stopped the initial no-start sequence with another push of the button, or if it timed out itself.
But a second try at starting was successful. No problems since.

Hopefully it never happens again. Will post if it does.
 
#518 ·
I have a 2021 GMC Sierra 1500 AT4 with the 3.0 Duramax that is 4 weeks old with 2500 miles. The following has happened three times. I press the brake, press the start button, the engine turns over for approximately 10 seconds without starting. Each of the three times it has started on the next attempt.

The dealer looked at it after the second time and could find nothing wrong.

After reading this thread it appears to be more than an isolated case.
My suburban was doing that too. I found out that when I was in a hurry is when it would always happen. It appears to me I wasn’t giving the computers enough to wake up. Haven’t had this issue since I started getting in and putting my seatbelt on and pressing the brake pedal while doing so before I try to start the truck. It was doing it pretty regularly before that. I’ve been an automotive tech for over 20 years and have seen this type of problem with all kinds of vehicles since they got have gotten rid of the mechanical ignition switch. It seems even worse on vehicles with push button start. Hopefully this is your problem as there are many other factors that could be
 
#14 ·
My 21 Silverado with the 3.0 is 5 weeks old, with 1500 miles. I have had the starter issue 3 times so far. Last week was the worst. I came out of the doctors office , stepped on the brake, pushed the starter button. I think it cranked for 30 seconds before it stopped. I feel so helpless because there's nothing I can do to stop it. I called two dealers and both said they never heard of the issue. Both were unaware of being able to pull up a trouble code on it. Both also said the same B.S. story about if we can't duplicate it, we won't fix it. I'm turning my camera video on every time now before I try starting. Hopefully I can video it. I've got an appointment to see if the tech's can pull up any codes. Dealer wanted me to leave it for a few days to see if they could duplicate it. I said NO! that's my only means of transportation. Maybe if enough of us with the issue complain, GM will do something about it. Let's keep each other informed.
 
#388 ·
I have a 2021 Silverado High Country with a Duramax, I have 10,000 miles. It is kept inside garage all the time. One morning went out to go somewhere, pushed the start button, and stater keep spinning and would not start, tried everything to stop the starter, after about 10-15 seconds it stopped. Tried again, did same thing, tried again and it started. Took in to dealer, and it did the same thing while I was showing them. Left it for them to check. They called and said that code showed low battary whitch I am sure it showed this code, due to starter turning over and over. They called and said it was ready and battary was charged. I went to go pick up, and while I was there, did same thing. So I left it there. The next week I called, said they found battery cable loose, working good now. Drove home and parked outside, then later on that afternoon, I was going to put in garage, and starter di9d same thing again. I was getting pissed, they contacted GM technical support and they told them they needed to run a scope down in engine to check the cam timing on selector wheel (what ever that is). Of course they had to order all tools required to do this check. Just talked with them on the phone, they got tools in this morning and they should know results this afternoon. They did say, they hoped this was not the problem that is would take some time to repair the problem. I will give update.
 
#15 ·
Dang ‘puters

There is a “start sequence” of course.
Do you recall the oil pressure immediately after it lights up? I ask because if the engine does get ”oil pressure good”, and fuel pressure good, it starts firing injectors, then it gets happy.

I have seen the sequence documented somewhere...

Also, should the “attempt start” button, bounce or fail to release internally there won’t be a “start” as the ‘puter will throw a hissy-fit as it isn’t liking a stuck switch.

This is somewhat “normal” .. should the “start” button is pressed and before it starts the driver hits it again, the ‘puter sees that as a “try to start, never mind, shut off” sequence. That’s how it works on my brides’ button car.

So my “dealer questions”:
  • does it get oil pressure? (If not it is damaging the crankshaft main journals.
  • have you replaced the start button?
  • have you replaced the brake safety interlock?
  • how about anti-theft feature error (is On-stare doing a vehicle disable command?... yes, they have been hacked before and I doubt the dealer will research..
  • loaner vehicle.
  • safety issue.. who pays when it shuts down on the interstate?
  • document time, mileage, location of failures for Lemon Law.
  • remain calm when discussing.
  • contact GM rep
 
#17 ·
I have a 2021 GMC Sierra 1500 AT4 with the 3.0 Duramax that is 4 weeks old with 2500 miles. The following has happened three times. I press the brake, press the start button, the engine turns over for approximately 10 seconds without starting. Each of the three times it has started on the next attempt.

The dealer looked at it after the second time and could find nothing wrong.

After reading this thread it appears to be more than an isolated case.
 
#171 ·
After I made this post the same thing happened twice, then no problems for two months. Since then it has happened five more times plus once where it took approximately 10 tries for it to start.

The dealership is still saying they have heard nothing about this, even though I have two friends with the exact same problem.
 
#18 ·
Do these trucks have the auto stop/start system? If so, is there a relation between the observed problems and this system? Just wondering to myself.
 
#19 ·
Start button (or key) on late model GM's) isn't connected directly to the starter.

Button or key sends signal to the computer, and the computer does a start cycle.

Quickly press and release the button, or 'bump' the key and the truck will go thru whatever glowplug cycle is required (based on temps) and then continue with the start cycle.

Either they aren't seeing correct feedback from one of the sensors, so not requesting injection -- or the injection request isn't being acted on.
Sensor issue or connection issue seems likely.
 
#22 ·
There is a lengthier thread on this subject on the gm truck forum, see here: Won't start ?

There is a service bulletin about loose bolts connecting together the under hood fuse block. I have been having the same starting issues and found that mine were loose as well. It's only been a week or so, but have not had any failed start attempts since
Wow, what an eye opener. I've got a few bolts I'm going to check torque on based on that thread.
 
#23 ·
I also have had this same problem. The first time it happened, truck had 150km. Brought it to the dealer and was told problem was fixed. I was told it was a camshaft sensor. I also told them about the no start long crank issue with the gas jobs and said make sure the ECM is up to date. It did throw an engine light. No start happened again 100km later. Brought the truck back to the dealer. That was on April 13th. Truck is still in the dealer as we speak. They tried a new ECM. Problem persisted. The no start happened in their shop. Then they said they need to pull the cab to get access to the timing cover to look at the timing ring on the camshaft. Also just got a call yesterday saying the GM engineers are coming down to look at the engine. I’ll keep you guys updated. Confirming I have the same problem. Long crank, maybe 20-30 seconds and you can do nothing to stop the crank minus remove the battery terminals. Then it fires right up. For me though, problem was worse after they changed the camshaft sensor and updated the ECU. I have a feeling this is all software related.
 
#24 ·
Have the same problem, less than 600 miles. Hit the start button and it just cranked for about 10 secs, hit the start button again and that stopped it cranking. Hit the start button again and it started right up. Waited about an hour and tried starting it again this time with the remote and it just cranked and no start. I hit the remote after about 5 secs and it shut it down. Hit the start button in the cab and it started right up. Now waiting to see if anyone gets an answer from the dealer before I take it in.
 
#26 · (Edited)
I got the 21 GMC Sierra AT4 a month ago and the crank no start issue happened with 300 miles on it and now with 1100 miles on it. Second try it'll start, as of now, this might change but who knows at this point.

Now GM, just think if this happens at an intersection with the tree hugging auto engine off feature engaged.

Doesn't sound like anyone has had luck with this issue yet and I'm sure GM has no clue, they'll probably say it has covid. Anyway I will be monitoring the thread, Thanks for reading.
 
#29 ·
Lift your foot almost off the brake so it restarts and then put it back down.

Once restarted it won't stop again until it has reached the minimum speed threshold


Auto Stops may not occur and/or Auto Starts may occur because:

. The climate control settings require the engine to be running to cool or heat the vehicle interior.
. The vehicle battery charge is low.
. The vehicle battery has recently been disconnected.
. Minimum vehicle speed has not been reached since the last Auto Stop.
. The accelerator pedal is pressed.
. The engine or transmission is not at the required operating temperature.
. The outside temperature is not in the required operating range.
. The vehicle is in any gear other than D (Drive).
. Tow/Haul Mode or other driver modes have been selected.
. The vehicle is on a steep hill or grade.
. The driver door has been opened or the driver seat belt has been unbuckled.
. The hood has been opened.
. The Auto Stop has reached the maximum allowed time.
 
#28 ·
#31 ·
oh my, I was emailing a friend about a watering system for the plants and thought I had the answer. But I think the answer has now been published.
 
#32 ·
Well it happened a second time yesterday. Currently @ 4,7xx miles. Tried to turn the truck off with no success during the extended starter run. Waited 30 seconds for a second try at starting and it fired right up.

I'll talk to my service advisor about it when I see him in a few weeks.
 
#33 ·
It is only necessary to 'bump' the key or start button.
(try it! Start position of key or button only needs to be 'on' for an instant.)

Signal from key/button is to computer.
Computer then initiates the start sequence - including glow plugs and any checks it wants done, then activates the starter.
This computer logic was in place before the introduction of auto stop/start systems.


If it doesn't start, the computer will 'give up' after xy seconds of cranking.
 
#36 ·
Well, I solved my no start issue. Of course not in a way that will help anyone else.
After 3 months and 5,000 miles of driving the GMC, I wasn't real happy with the quality and technology of a supposedly top of the line truck.

I traded in on a 2021 Ram 1500 Limited Ecodiesel. With the truck market the way it is now, the dealer gave me $1,000 more for trade than I paid for the truck. Couldn't be happier.

Hope GM gets the no start issue figured out.
 
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