What is Happening Here?

[Ereynolds72]

This has happened a couple time recently when the engine is cold and allowed to idle without engaging the engine brake button. The truck is a 2010 deleted with SmartyJr67 and has 355k miles on it. There's no power, a lot of smoke, and a loud grumble coming from the intake area. It acts like something is not opening to allow the air to pass through. The 1st time it happened I was able to correct it just by turning the engine off and restarting. The next two times, I restarted a couple times without success. I hooked up the Smarty and loaded a different engine tune. No codes when I hook up the Smarty. I run the stock intake box with good filters. When it corrects it drives and acts like normal.
https://youtube.com/shorts/T7bCRHt2DZk?feature=share
Any ideas?

 

[Signal73]

This has happened a couple time recently when the engine is cold and allowed to idle without engaging the engine brake button. The truck is a 2010 deleted with SmartyJr67 and has 355k miles on it. There's no power, a lot of smoke, and a loud grumble coming from the intake area. It acts like something is not opening to allow the air to pass through. The 1st time it happened I was able to correct it just by turning the engine off and restarting. The next two times, I restarted a couple times without success. I hooked up the Smarty and loaded a different engine tune. No codes when I hook up the Smarty. I run the stock intake box with good filters. When it corrects it drives and acts like normal.
https://youtube.com/shorts/T7bCRHt2DZk?feature=share
Any ideas?

Sounds to me like your turbo vanes aren’t functioning as designed and not making the low end boost needed to burn the fuel your injectors are putting out.

 

[petersonj]

I agree. Your truck uses a variable geometry turbo. The variable part is inside the turbine side. The sliding part is likely stuck in the low rpm zone, therefore not allowing boost to build as engine load increases. These VG turbos can be problematic - especially if the operator rarely uses the exhaust brake which forces full travel of the variable part.

- John

 

[Ereynolds72]

That makes sense. I normally hit the exhaust brake button every time I start the engine. I didn't this morning and it's likely I did not on the other two occasions. Is this something that can be addressed by cleaning inside the turbo? Is there a maintenance item I'm missing here?
Thanks!

 

[petersonj]

I really don't have experience with VG turbo maintenance / repairs. You probably should check for any trouble codes that may be set. I think one problem could be some sooting issues which would require some method of cleaning and another problem could be a failing electronic actuator.

There will probably be some posts soon from people with much more experience than I have.

- John

 

[Ereynolds72]

As a follow-up to this topic, I'm about 99% sure it's the throttle valve sticking on the intake side of the engine. I've ordered one of those "pusher" style intake horns to replace the stock intake and throttle valve assembly. It should be here tomorrow. I'll follow up here again with the results.

 

[petersonj]

As a follow-up to this topic, I'm about 99% sure it's the throttle valve sticking on the intake side of the engine

Well, I learned something today. I didn't know there was a throttle valve in the intake system. After doing some reading, I understand that it is used in conjunction with EGR control for exhaust emissions. I will be interested to see if that is the problem with your truck.

- John

 

[Ereynolds72]

In an instance where this was happening to my truck, I tapped on the throttle valve assembly with a hammer and it opened up. This convinced me I was on the right track. I've since replaced the intake horn with one of those "pusher-style" intakes and the event has not duplicated. An $80 ebay part and about an hour of my time and it's fixed. So thankful it wasn't on the other side of the engine.
The reason it wasn't throwing any codes was because the program didn't recognize that there was even a throttle valve assembly there anymore.