So first off the truck is a 2004 Silverado 1500. I’ve had the truck for 15 years. Ever since I can remember I’ve had this noise occasionally during wot pulls. Even when the truck was stock!

now it has a truck Norris nsr cam and gt45 eBay turbo. With decapped injectors and 340 fuel pump. I’ve got the truck running pretty well, but still have this higher rpm rattle noise. I’ll put a video up to hear the noise.

https://m.youtube.com/shorts/ByagZKKU2aE

 

Pinging....
Which octane do you use??

 

Does sound like pinging, but what ware the odds you have dentation in the same rpm range with multiple different tunes and yet you still haven't melted a piston or blew a head gasket.... I guess its possible.....

Whats your timing at under boost in that RPM range?

 

Detonation, back it down a couple of degrees. It's the Knock Sensors tipping in to control that Detonation why the Engine hasn't blown up.

My truck did it until I pulled the timing down, doesn't do it anymore. Just what it is.

 

Wow! Thanks for all the responses. I was thinking spark knock too. I thought I had it at 13 degrees at that rpm but I just checked and it was 18. So I think you guys are correct. I’m lowering the spark in both tables. Sometimes I am cheap and run 87 but it does gets 91 or better. Mind you this is only on 5psi max. Just swapped over to speed density and turns out I was fighting a bad maf before.

thanks for the help! I will let you know if this is fixed by lowering the spark tables.

 

Just for a data point:
I can only get 90 Octane Unleaded here- I've dropped back to 6 degrees spark in the 4000 -4400 columns, back up to 11 degrees up top.

 

Looking for a problem?
Reading the plugs comes to mind....

 

Thanks guys!

Yeah I have had three sets of plugs if not 4. Every time I’ve checked them the plugs looked great. I’m not an expert plug reader such as your self. I have yet to be able to fix the problem on my own.

Thankfully this forum has nice, intelligent, and thoughtful people here that have actually gave me worthwhile feedback on my video. Those member have potentially helped me fixed my problem I’ve had all these years.

 

Reading with miles on them is not the best.
However, some very good pics of them can give clues as to what's going on.

 

What's the tune/datalog look like when it's rattling?

Oh wait....why would you need that info?

 

"I’m not an expert plug reader such as your self".
Yep. I am an expert at all things forced induction!

 

"It's only got 25 degrees of timing at 10psi on 87 octane"

 

thats what your ex told me would work

 

Wow man...you are going to have to do A LOT better than that.

Have some respect for yourself next time and just not reply.

Anyway....do you have a datalog of it when it's rattling?

 

Looks like the wiseass has been distracted.
Maybe changing head gaskets?
"I was thinking spark knock too. I thought I had it at 13 degrees at that rpm but I just checked and it was 18. Mind you this is only on 5psi max".
Same on the boost.. Thot it was 5, but is really 15??

 

I have lowered the spark and still have been getting the KR around 2500-3000 just on initial throttle tip in. Could be false knock. I’ve put 93 octane in it and that didn’t change it. The problem went away for the most part now though from lowering timing in that upper rpm range.

lol luckily not changing head gaskets at the moment. Thanks for wishing that on me! Instead though, Christmas Day I was driving to go get my daughter and my 4l60e lost all movement! So there is my bad karma! Hopefully you can be happy about that.

now time to upgrade to a 4l80e. That 4l60e had already been rebuilt and upgraded. I gave it a fair shake.