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Rattle with throttle

geswek

By geswek
in Troubleshooting & Recalls

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geswek Enthusiast

geswek

Posted
Posted

I am running a canned tune in my Diablo sport; 87 octane tune, firm shift TCM, AFM off, TM off, 20% throttle boost.

 

When I am cruising at 30mph, 40mph; if I give it just the right amount of throttle--I hear some kind of rattle and then the engine noise happens (sound when you are throttling up.) I can literally do it on command for the most part. It goes away whenever the engine noise raises.

 

Is it the AFM lifters? My buddy has a tuned truck and SWEARS he can't hear it on his. He has an SB intake (I'm just stock intake). I had him with me when I did it one day.

 

Overall the truck runs fine--just odd noise I can't place.

dascenc Enthusiast

dascenc

Posted
Posted

Mine is completely stock and does the same thing under moderate/heavy throttle. Kinda sounds like a paint can being shaken, it's definitely mechanical. Hope someone can chime in.

Bassinz71 Enthusiast

Bassinz71

Posted
Posted

My 2014 5.3 does the same thing, bone stock. I have had it to the dealer twice and it took multiple ride alongs before they admitted hearing it. Chevy paid for a top engine chemical clean but it literally did nothing. Im calling GM this week to try and get it taken care off. Dealer basically said 'oh well, you have a 100k mile warranty so you'll be fine'...thanks. Sounds pretty nasty so I just don't punch it anymore but IMO it needs to be taken care of.

  • 2 weeks later...
geswek Enthusiast

geswek

Posted
  • Author
Posted

I removed the canned Diablo tune for an oil change and noticed that rattle (or marbles in tin can) is gone. I'm guessing it's the AFM lifters and something just wants to make noise.

 

It's really hard to hear it with AFM enabled since any light pressure kicks it to V8 mode.

bagger97 Enthusiast

bagger97

Posted
Posted

Sounds more like crap gas, try running w/o the tune in M5 and see if it still does it.

geswek Enthusiast

geswek

Posted
  • Author
Posted

It happened when we were in Texas over Easter. 1200 miles away. Bad fuel I can't agree with.

 

I retuned the truck today with no throttle boost or TM off. I can't get it to replicate now.

 

 

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neokonig Enthusiast

neokonig

Posted
Posted

I have noticed a similar type of noise. Though, I believe it is because the exhaust and cat are so close to the floor on the driver side,

I have thought about the location of the noise and seems consistent with the placement of the exhaust. My last truck, which was a '10 6.2, did the same exact thing. At a certain throttle position you can hear a rattle like noise, with my last truck I used an undercoating in the body above the exhaust part and it dampened it a little but, I am thinking there is not a good solution.

geswek Enthusiast

geswek

Posted
  • Author
Posted

I retract my statement..... It is still rattling! It seems to happen for sure at 55mph when I'm driving.

 

 

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geswek Enthusiast

geswek

Posted
  • Author
Posted

If it's detonation, it's not good.

I don't think it is.

 

I cruise at 55 and when I apply throttle to increase speed, that is when it rattles a bit and then goes away.

 

At least that is what I think. LOL

If it's detonation, it's not good.

I don't think it is.

 

I cruise at 55 and when I apply throttle to increase speed, that is when it rattles a bit and then goes away.

 

At least that is what I think. LOL

geswek Enthusiast

geswek

Posted
  • Author
Posted

You say you run 87, try 89 octane and see what happens.

I've tried 93 octane and it didn't make a change. It was doing it on our road trip to Texas over Easter as well. Bad fuel was my first thought.

geswek Enthusiast

geswek

Posted
  • Author
Posted

I got video, ignore wind and you should be able to hear it. I returned truck to stock programming and it won't replicate which leads me towards the lifters and I only hear it because I have AFM disabled.

 

https://vimeo.com/163396814

 

 

 

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tallspawn Enthusiast

tallspawn

Posted
Posted

I got video, ignore wind and you should be able to hear it. I returned truck to stock programming and it won't replicate which leads me towards the lifters and I only hear it because I have AFM disabled.

 

https://vimeo.com/163396814

 

 

 

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I have been hearing something since I changed mufflers, could hear it faintly at idle so I reached under and held the flapper open and it stopped. I'm not sure where exactly yours is coming from or if you still have it but worth checking....

 

Sent From My Galaxy S6 Edge+

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