3.0 Duramax cranks but won’t start

moobaru · August 25, 2021

3 minutes ago, Barrett10 said:

Talked to the service department yesterday, the new reluctor wheel that came in is bent. They have to order another one…

Bent from the factory... amazing!

Barrett10 · August 25, 2021

3 minutes ago, moobaru said:

Bent from the factory... amazing!

Yep, crazy

Frankhpns · August 25, 2021

I would love to know who supplied all these reluctor wheels. I can't believe that even the replacement wheels are ben also. They must not have any QC at GM at all.

Barrett10 · August 25, 2021

16 minutes ago, Frankhpns said:

I would love to know who supplied all these reluctor wheels. I can't believe that even the replacement wheels are ben also. They must not have any QC at GM at all.

CCP

3.0duramax · August 25, 2021

Update. Just got my truck back after 3 months. Yes 3 whole months exactly. They replaced the exciter wheel and added the 0.5mm shim. Had her for about 10 mins before the engine light came on and no AC. Back to dealer tmr. Will update again when i find out the issue

coinman · August 26, 2021

On 8/24/2021 at 2:48 PM, Barrett10 said:

More pictures

WOW.... your truck won't be the same when put back together.

Barrett10 · August 26, 2021

2 minutes ago, coinman said:

WOW.... your truck won't be the same when put back together.

Not my truck, GM’s truck …

fireaxxe · August 27, 2021

There is something seriously wrong with these trucks. Yesterday while driving it went into regen and the engine was making the most god awful fuel knock I have ever heard. I am guessing if the cam sensor or reluctor/exciter wheel is the issue with the no start then the timing must be off while running at times as well. This would explain the fuel knock. I don’t believe the crank no start is the only issue related to this problem. There is no way this aluminum diesel will hold up to that. Yesterday I went to my purchasing dealer and requested a buy-back.

MPX1 · August 27, 2021

Hey guys - 2021 Sierra AT4 here purchased in April of 2021. I have 4700 miles on the truck and just had a no-start for the first time this morning, but it was during a remote start.

I immediately opened the door and looked at the DIC and saw a message that said something to the effect of "service steering column" before it disappeared. Sorry that I don't have the exact message. I got a half-second glimpse of it before it went away and never came back. Truck turned over instantly afterward when I pressed the start button.

I've read all 21 pages of this thread and it looks like this issue is still a ghost. Does that sound about right?

Good on all of you for doing God's work here and trying to figure this thing out. Would be better if GM would just do it.

Barrett10 · August 27, 2021

11 hours ago, Barrett10 said:

Not my truck, GM’s truck …

Just got the official call from GM today after lots of pursuing, emails and phone calls that they are going to do a re-purchase.

GJR1212 · August 27, 2021

15 minutes ago, fireaxxe said:

There is something seriously wrong with these trucks. Yesterday while driving it went into regen and the engine was making the most god awful fuel knock I have ever heard. I am guessing if the cam sensor or reluctor/exciter wheel is the issue with the no start then the timing must be off while running at times as well. This would explain the fuel knock. I don’t believe the crank no start is the only issue related to this problem. There is no way this aluminum diesel will hold up to that. Yesterday I went to my purchasing dealer and requested a buy-back.

No spark plugs in Diesel engines. My guess, the cam sensor and infamous exciter wheel are used for timing of the direct injectors pulses and, mostly likely, for the control of variable cam timing. These 3.0 inline 6 cylinder engines appear to be very similar to the VW TDI 2.0 inline 4 cylinder engines which are also all Aluminum. The VW engines seem to be reliable. I have a 2015 TDI Golf wagen. I liked it so much, I opted for the 3.0 GMC to replace my old truck. Mine has done the long start once in 3000 miles. Other than the fuel mileage going to pot, I can't tell when the GMC is in regen. Regeneration seem to kill the fuel mileage to about 70% of what you normally see.

Bad fuel causes Pre ignition knocking. Any chance you got some bad diesel? Carbon build up can also cause pre ignition.

singlespeed · August 27, 2021

On 8/24/2021 at 2:58 PM, Joe Brooks said:

Has anyone has the “shim” installed on the cam shaft position sensor long enough to know if that fixed the issue?

That's a great question...

fireaxxe · August 27, 2021

22 hours ago, GJR1212 said:

No spark plugs in Diesel engines. My guess, the cam sensor and infamous exciter wheel are used for timing of the direct injectors pulses and, mostly likely, for the control of variable cam timing. These 3.0 inline 6 cylinder engines appear to be very similar to the VW TDI 2.0 inline 4 cylinder engines which are also all Aluminum. The VW engines seem to be reliable. I have a 2015 TDI Golf wagen. I liked it so much, I opted for the 3.0 GMC to replace my old truck. Mine has done the long start once in 3000 miles. Other than the fuel mileage going to pot, I can't tell when the GMC is in regen. Regeneration seem to kill the fuel mileage to about 70% of what you normally see.

Bad fuel causes Pre ignition knocking. Any chance you got some bad diesel? Carbon build up can also cause pre ignition.

I am FULLY aware there are no spark plugs in a Diesel engine. This is why I specifically said FUEL KNOCK. The timing of the Diesel engine is determined by the fuel delivery to the compression of the air that generates heat in the cylinder. In order to know when to deliver fuel the ecu looks at a number of sensors specifically the crankshaft position sensor and camshaft position sensor. So to reiterate my point, if there is an issue with the cam sensor this could cause not only a no start issue but also mistiming of the power stroke causing fuel knock and engine damage.

I don’t think the 3.0 duramax has VVT

The fuel was tested by a lab and was good and I only have a few thousand miles so no chance of significant carbon build up to cause a fuel knock. There is something wrong with these trucks.

Edited August 27, 2021 by fireaxxe

fireaxxe · August 27, 2021

22 hours ago, MPX1 said:

Hey guys - 2021 Sierra AT4 here purchased in April of 2021. I have 4700 miles on the truck and just had a no-start for the first time this morning, but it was during a remote start.

I immediately opened the door and looked at the DIC and saw a message that said something to the effect of "service steering column" before it disappeared. Sorry that I don't have the exact message. I got a half-second glimpse of it before it went away and never came back. Truck turned over instantly afterward when I pressed the start button.

I've read all 21 pages of this thread and it looks like this issue is still a ghost. Does that sound about right?

Good on all of you for doing God's work here and trying to figure this thing out. Would be better if GM would just do it.

I have also seen the “Service steering column lock” message but it was when the wheel was turned and once I put pressure on the steering wheel to take the weight off the column lock I heard it click and the truck started just fine. Message has never come back.

GJR1212 · August 28, 2021

26 minutes ago, fireaxxe said:

I am FULLY aware there are no spark plugs in a Diesel engine. This is why I specifically said FUEL KNOCK. The timing of the Diesel engine is determined by the fuel delivery to the compression of the air that generates heat in the cylinder. In order to know when to deliver fuel the ecu looks at a number of sensors specifically the crankshaft position sensor and camshaft position sensor. So to reiterate my point, if there is an issue with the cam sensor this could cause not only a no start issue but also mistiming of the power stroke causing fuel knock and engine damage.

I don’t think the 3.0 duramax has VVT

The fuel was tested by a lab and was good and I only have a few thousand miles so no chance of significant carbon build up to cause a fuel knock. There is something wrong with these trucks.

Sorry, I misread your earlier comments. So far I am pleased with how the 3.0 runs and how well the 10 speed compliments the engine. I hope you are wrong about there being a fundamental flaw in the design. You may recall the fiasco in the mid 80's when GM tried to make a diesel v8 out of a gas v8. That was a flawed design for sure. My point was this engine seems very similar to the TDi design that runs a great number of euro cars and still a few here.

I do think carbon build up could happen quickly when running excess fuel over a hot exhaust valve. Perhaps your truck has some problem with the regen fuel enrichment controls. I did see on one of these forum someone else complaining about knocking, I wonder if this is problem is common to the design or more something specific to a few offending trucks?.