3.0 Duramax cranks but won’t start

[ColoradoCub]

There’s a bunch of videos of these trucks doing the crank no start on YouTube uploaded by owners from forums and Facebook pages.

 

https://www.youtube.com/results?search_query=3.0+duramax+cranks+but+wont+start

Edited July 21, 2021 by ColoradoCub

[SC GMC AT4]

I have GMC Sierra AT4 duramax 3.0 and have this same issue. Has now happened approximately 10 times and I have 2500 miles on truck. Seems to happen when I park my truck on on a slight incline. Always starts on second try. Will be following this thread.

[mjm5247]

2021 GMC Elevation 3.0 Duramax.  Same issue has happened twice now (1,000 miles on the truck).  First time at 600 miles (push button start) and most recently at 1,000 miles (key fob start).  Frustrating because otherwise the truck is great.  It would be nice to see more feedback from GM.  

[Jacob D]

I'm just curious but anyone having the start issues also run into any issues with starting the truck and having no power steering? That has happened to me twice as well.

[Frankhpns]

On 7/20/2021 at 9:53 AM, 3.0duramax said:

I had my truck for 20 days and in that time it happened 2 times. 2021 silverado RST 3.0l diesel. So far the truck has been in the garage for 48 days, ive been driving a 17 silverado the dealer just got traded in. They have been waiting on parts to fix the exciter wheel, last week the parts came but one was damaged when they got it, im thinking they received another bent exciter wheel. I requested a new truck and that was "being worked on" by GM but when they heard the parts where in they threw that out the window and are planning on making my payments for some time, the manager at the dealer told me maybe 6 months payments. If that is the case I wont be entirely disappointed with the service but from what I am seeing this may not even fix the problem, besides the fact I will have no trust left in the truck after being completely tore down to do the job. For now I am very frustrated but being patient because at least I have a truck to drive. Depending on what they do for me when i get the truck back and if the problem is fixed in the end it might not be such a bad thing. Time will tell. 

After talking with the mechanic who is repairing mine, he told me that he was in contact with the GM engineers working to resolve the problem. He started that there are about 18,000 engines that have the problem and they are trying to figure out if the bent exciter is due to the vendor supply or damaged during installation. There also might be a secondary problem with the high pressure fuel pump causing the same symptoms.

[Frankhpns]

On 6/2/2021 at 2:21 PM, ruby li said:

“Bent trigger Wheel” is what GMs bulletin said. I took it to dealership and they searched for bulletins and found that. 
I guess I will know next week, when they replace the part( being shipped) whether the trigger wheel is bent or not. 

After talking with the mechanic who is repairing mine, he told me that he was in contact with the GM engineers working to resolve the problem. He started that there are about 18,000 engines that have the problem and they are trying to figure out if the bent exciter is due to the vendor supply or damaged during installation. There also might be a secondary problem with the high pressure fuel pump causing the same symptoms.

[ColoradoCub]

There is definitely a secondary problem because there are a ton of trucks with this problem that have been inspected and do NOT have a bent exciter wheel, yet they have the exact same problem. That exciter wheel is not the problem!

[mjm5247]

1 hour ago, ColoradoCub said:

There is definitely a secondary problem because there are a ton of trucks with this problem that have been inspected and do NOT have a bent exciter wheel, yet they have the exact same problem. That exciter wheel is not the problem!

This makes sense with what we have seen in this thread. 
 

Not sure if this makes sense, but if the problem was mechanical, say the exciter wheel for example, would we not see more frequent reoccurrences? Not every couple hundred miles and a number of starts in between as commonly reported here. 

[Claire Buenavides]

How can a new truck malfunction? That is so weird, it will be best to contact a dealer store if this is the issue right? 

[Frankhpns]

9 hours ago, ColoradoCub said:

There is definitely a secondary problem because there are a ton of trucks with this problem that have been inspected and do NOT have a bent exciter wheel, yet they have the exact same problem. That exciter wheel is not the problem!

I have been told by my mechanic who is speaking with GM engineers that there are roughly 18000 trucks with the problem. In addition the mechanic was instructed to check the fuel pump in addition to the defective cam position sensor exciter. Apparently the symptoms are similar and they have had returns of vehicles after the exciter repair that required a fuel pump change. I inspected my defective cam position sensor exciter and it is definitely bent. The exciter is not bent by a few thousands which would not be noticeable with out a dial indicator rurnout measurement but at least a 1/4 inch on one of it's tabs.

[GJR1212]

5 hours ago, Frankhpns said:

I have been told by my mechanic who is speaking with GM engineers that there are roughly 18000 trucks with the problem. In addition the mechanic was instructed to check the fuel pump in addition to the defective cam position sensor exciter. Apparently the symptoms are similar and they have had returns of vehicles after the exciter repair that required a fuel pump change. I inspected my defective cam position sensor exciter and it is definitely bent. The exciter is not bent by a few thousands which would not be noticeable with out a dial indicator rurnout measurement but at least a 1/4 inch on one of it's tabs.

Is it a pretty straight forward job to pull the valve cover?   My March 2021 build date GMC has only done the long start once, but my dealer over in Daphne avers that this is the first time he heard of such a problem.....    No help.   All they know is to read the code and then replace, on GM's nickel, the easiest to change out parts.

 

 

[Claxy515]

Just had my second experience with the no start at 1800 miles on my 2021 Silverado 1500 3.0L Diesel. First start of the day, foot was nowhere near the gas pedal - I know because I'm not wearing shoes. Fired right up after the second try.

[Camille]

On 7/20/2021 at 12:37 PM, MNJoel said:

Anyone with this issue on higher mileage diesels (greater than 5k)?

 

Mine had three instances all under 1100miles. Currently at 5500 miles and no instances since 1100

I had this happen to me the first time at 4300 miles & again today at 6500 miles

[Claxy515]

Also, my pickup build date was May 5, 2021, and it's happened twice now.

[gemarsh]

On 7/20/2021 at 11:37 AM, MNJoel said:

Anyone with this issue on higher mileage diesels (greater than 5k)?

 

Mine had three instances all under 1100miles. Currently at 5500 miles and no instances since 1100

Never have had this problem and have 14,200 miles on it. 2021 GMC Denali.