Machine gun sound durring hard acceleration - V6

AlphaQup

AlphaQup

New member
Alright guys, let me kinda discribe how I came about this "Machine gun" sound. As I was driving my wife to work, I opened all my window for the first time. What can I say, it was a nice day after a whole month of record rainfall. Anyway, as I made a left turn into another street, there was a center median seperating the expressway I was on. I was sitting in the lane closest to the median and you all know when you're next to it you can hear every sound your car makes. Well, in my case I decided to gun it and then thats when I heard the "Machine gun". That's the best discription I can give, or maybe even a helocopter sound. The truck only has ~3000 miles on it so far (SE V6 4x4). I wouldn't think this sound is normal for such a new vehicle, but my question to everyone is, "Is this Normal?" I've done a search already and came up with some of the V8 guys with a "Helocopter " sound, but their problems were only at 70+ mph. My sound starts anytime you accelerate HARD. I wouldn't say its a vibration either, because I cant feel it or let alone hear it with all the windows up. What do you guys think this is? Should I not even worry about it? :confused:
 
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Hmmm, that's odd. It wasn't detonation you heard, was it? Maybe cheap gas? Was it was a fluttering sound ? Could have been the cats if it wasn't very loud. Hard to say. :confused:
 
That sound is normal for the V6. It is the fuel injectors making that noise. Not sure if the aluminum block magnifies the noise because this is Toyota's first all aluminum engine.

Disconcerning when you hear it for the first time, but apparently it is normal.
 
sharp4runr said:
That sound is normal for the V6. It is the fuel injectors making that noise. Not sure if the aluminum block magnifies the noise because this is Toyota's first all aluminum engine.

Disconcerning when you hear it for the first time, but apparently it is normal.
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:iagree:

Same thing my V6 did and it drove me nutts.

As far as I have read, it seems to be the valves tapping. Notorious issue with the V6.
CV
 
thanks for the sigh of releif guys. It couldn't be bad gas since all I've been using is Cheveron 87 octane gas. The sound is pretty annoying, but if it's normal like some of you say, I'll just learn to block it out.
 
My 2003 SE V6 did the same thing. If you search "engine ticking" you will hear MANY more stories about this. I did find though that different gas produces different levels of loudness. For me it was just TOO annoying that I traded in my 2003 SE V6 for a 2005 SE V8 and never looked back. Happy as a clam now. It made me feel like I was driving some junkyard vehicle. I don't think a new vehicle should sound like that...but if you can get used to it then its normal.
 
Don't worry about the tapping, Alpha. It is indeed the valves opening and closing. I've read that the V6's alum block may not insulate the sound as well as the V8's iron block. I guess it can be considered normal for the V6. Mine does it too under harder acceleration. However, I also like the fact that my V6 has a distinct "growl" when accelerating. The center median could have also bounced the sound waves back at you making it appear louder than what it really is.
 
All of those 4.0L's come standard with that sound under load. I've heard it described as everything from a busted lifter to exhaust manifold leak.....but it's nothing, just normal.

FWIW, it's MUCH more pronounced in V6 auto Tacomas than the 4R. It bugs me too, but there's no dealer/factory solution so far.

Maybe an aftermarket air box and exhaust would make enough other racket that you wouldn't notice it.....any of the V6 guys have luck with either?
 
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I just got my '06 V6 SE, and I thought it sounded like the fan or fan belt was a little loose.

It's kind of a soft 'fan-type' sound when accelarating? It doesn't bother me much, I just want to make sure there is no problem
 
The machine gun sound you hear coming from the engine is those "overpriced" gasoline dollars being blown through your exhaust system!
:awais:
 
fo'runner said:
The machine gun sound you hear coming from the engine is those "overpriced" gasoline dollars being blown through your exhaust system!
:awais:
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So now it's an exhaust issue? I thought everyone else said it was the valves tapping due to the all aluminum block? :confused:
 
AlphaQup said:
So now it's an exhaust issue? I thought everyone else said it was the valves tapping due to the all aluminum block? :confused:
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I think he was making a poke at the increasing gas prices ;):
 
According to the Tacoma sites if you throw in some Mobil 1 0w-40 (which protects at the same temps as 5w-30) and use a mobil 1 filter the noise will be all but gone. I put on the mobil filter and run 5w-30 mobil 1 (might switch to the 0-40 next time) and dont hear the noise much anymore. I noticed an almost immediate reduction after putting on the mobil 1 filter. I also use 93 octane. BTW, I dont think it has ever been confirmed exactly what causes the noise but rather that all 4.0s do it and it is not detrimental.
 
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