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Idle issue

nicks2014sierra

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nicks2014sierra Enthusiast

nicks2014sierra

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Anyone know why this is happening

 

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Anyone know why this is happening

 

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Is there a way to post videos here?

 

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nicks2014sierra Enthusiast

nicks2014sierra

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Gotta be more specific

 

 

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During a nutreal idal rooms fluctuate from 500 to 1000 with a rough rumble almost feels like truck wants to stall

 

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Brettm13 Enthusiast

Brettm13

Posted
Posted

I'm assuming there is no check engine light on, right?

If so, a thorough throttle body cleaning and relearning the throttle body parameters is where I'd start.

 

 

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2strokesmoke Enthusiast

2strokesmoke

Posted
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During a nutreal idal rooms fluctuate from 500 to 1000 with a rough rumble almost feels like truck wants to stall

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Remove spark plugs 1 and 7 look for oil soaked issues.

2strokesmoke Enthusiast

2strokesmoke

Posted
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If there is then what

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If your spark plugs (#1 and #7) are oil soaked, this could be causing your sporadic engine misfire.

These cylinders are known to be a problem with the AFM system. Infact they have been known to cause oil consumption when these valve lifters are in their collapsed state. While in their collapsed state the valves do not open or operate while in v4, and ecm will shut off fuel to 4 cylinders.

 

GM knows the many problems with this system, however the aluminum blocks engines have been known to have more failures over the Iron block engines with AFM of the same system.

 

Castrol oil with titanium will help out aluminum block engines greatly, by flow filling any voids to slow down oil "blow by" that occurs during v4 lifter collapse mode.

 

Oil consumption occours when piston rings and oil retainers load up with blow by oil. When rings and oil retainers fill with oil they start to gum up with "varnish" or impurities from oil and engine impurities, this stops the oil rings from "floating" move around (side to side) or center themselves to their cylinder's true wear centers. This centering process seals or reduces oil blow by removing stripping oil back to the oil sumpt pan.

 

One more problem with this AFM system is "oil foaming". Oil foaming occours when oil is aerated, and the introduction of air, reducing oil protection and psi values. This has been a problem with collapsing lifters failing because of foaming.

 

The PCV system also known as positive crankcase ventilation allows escaped gases to exit engine through means of the valve covers. The early AFM engines pulled oil out as well as gases. This caused oil loss issues, only to be pulled, recycled back into the engines cylinder to be reburned. This causes "varnish" build up starting the failure circle over again.

 

In conclusion the AFM system was designed to meet the "EPA" fuel usage per miles driven. This was a good theory but never truely thought out from an engineering point of view!

 

To those that aren't anal about the best true fuel numbers, should dissable this troubling system. If all your mileage is highway, then you stand to benefit from this system. The ones that drive city stop and go will be having foaming issues and early lifter failures for their futures.

 

Just my humble opinion.

 

Best of luck to you.

firecat_30 Enthusiast

firecat_30

Posted
Posted

AFM disabler and Diablo intune are the 2 I've heard that work to disable the AFM. There are others but those 2 you can just disable that and don't need to install a full tune changing fuel levels and timing or any other parameters of the truck. Be careful if you have a new truck or a truck with warranty though, using one of these could void it.

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