Jump to content

Recommended Posts

Posted (edited)

I have a 2009 GMC Sierra 1500 with a stock 5.3L and the truck has 211k miles. The engine was replaced with a Jasper engine 1000 miles ago, that has the AFM deleted, and since then I've noticed louder than normal engine noise through the intake while accelerating. Sounds like it has a cold air intake, but its the factory intake and air box. It acts like timing is retarded, yet all is normal on the scanner and no codes generated. I checked the whole intake system for cracks or splits but all is good and sealed. I'm beginning to think it's the programming from GM's latest calibration since I haven't found anything wrong elsewhere. As a tech of 35 years, I'm perplexed and I've even enlisted the help of at least 6 other techs, including the GMC dealer,  that just shrug their shoulders after checking it out because they're also perplexed. This is my last resort in an attempt to get to the bottom of this. Any help would be greatly appreciated. 

Edited by Lancer412
Spelling correction
Posted

You said the AFM boondoggle was deleted, which is great. I think the engine probably has an AFM delete kit which is new lifters, cam, valve springs, push rods, etc, which makes for a much, much better breathing engine. I would be very happy with it. You have 8 cylinders breathing air as they were meant to. Just my opinion since I have a 2013 GMC with the 5.3 LC9. It is programmed to not cut back to 4 cylinders, but it still isn't the air pump it's supposed to be. I reiterate that I believe you have a V8 engine doing what it's supposed to be doing.

  • 2 weeks later...
Posted

Update. Had it dyno tuned and all is good. Runs better than it did when it was new. Still say GM's programming was the problem. 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
×
×
  • Create New...