houtex

Before anyone asks/demands/whatever... yes. I did in fact search. And not just on this site. But man, I must not be using the exact words, and I'm tired of thinking...

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I've noticed lately that Awesome is exhibiting what I can only describe as a 'soft diesel' sound. Symptoms:

She only makes this noise when I'm accelerating, through 2000-2500 and on up, under load.
Not while decelerating, either in or out of gear. (5 speed trans)
Not at idle.
Not while revving with no load.
Not while holding at symptomatic RPMs (2000 3000, etc.)

Now... I'll admit that at first, it got me worried it was the cam phasers, but I've heard that improper maintenance (oil changes, wrong oil, no oil) would be the cause of that, and I guarantee you that every 5000 miles or less, that oil change happens, and the level is where it should be at all times. I've also read that the cam phasers issue would be at idle, and very pronounced. Not the case, so I'm pretty sure that's not what this is. I could be mistaken, of course, the internet lies sometimes, as we all know, right? Right.

I've come to the conclusion that crappy gas and/or tune up might be needed. Which I'll get to, she's not yet due for plugs, and I'm frankly a little scared about doing them. But I'll do it, as at 80K, it's probably time. I know the procedure... I just don't wanna do those plugs... yeesh...

But I'm asking for other unmodified 3v VVT 4.6L GT owners to speak up if they've had this weird noise, and if there was a specific thing that was done that made it go away. If y'all wouldn't mind. Or, hey, point me to a link/thread/page/whatever, and shame me for not finding it on my own while you're at it. I'll be ok with being blasted with "YOU SO STUPID!" if it means I get the info.

I'm figuring the summer blend ethanol'd gas and the not-so-cool temps, coupled with 80K sparks and maybe(?) a dirty MAF and perhaps another time to clean the throttle body, is causing a teensy bit of knockin'/pingin'.

Or... not?

Oh, yeah, and I also read somewhere that it's just a 'manly engine making manly noises'. Which is confusing, as Awesome is a 'she', so what the hell, girl...?

Anyway, in advance, I thank y'all muchly.

AlsCobra

Sounds like detonation. What octane are you running? Try a tank of premium. That should take care of it. I have to run the middle grade in my truck because it will ping with regular.

cdynaco

Maybe carboned up plug causing detonation? At 80k I'd do em. The longer you wait the harder it might be.

If the timing chain has stretched to the point the tensioner doesn't take up slack, could the slack side be making noise? (The load side would be taught under load.) Seems like there was a thread somewhere that a guy replaced the tensioner and arm because of rattle. I'm thinking the tensioner arm might be a composite material.

The link doesn't connect direct. You have to go to the site and follow the path. Then scroll down to #53 & 54. I tried but it wouldn't let me copy the diagram. Stinkin pdf.

http://iihs.net/fsm/?dir=162

Path -- Root » 2005 » Workshop Manuals » 3-Powertrain » GROUP 03 [Engine] » SECTION 303-01B [Engine - 4.6L (3V)] » DISASSEMBLY

(Try clicking disassembly here, then again on the header of the site)

houtex

92/93 premium at all times (you know how that 'supreme' can be not 93 sometimes... ) I simply cannot justify using the other stuff while saving a whopping $3 per tank and getting less MPGs for it.

I wouldn't know about the tensioner thing. Pretty interesting angle there... I'll have to read up on that. I know that site, thanks for the path, Charlie. Nicely done!

My thought is that this weekend, I will attempt (crossing fingers and all that) to extract the original one piece plugs. I have reviewed the entire procedure, and know what to expect. I simply hope I'm a lucky bastidge and they don't break.

Thinkin' maybe do the 1/8th turn, penetrating oil, wait for 2 hours. 1/8th turn, another shot of that oil, wait another hour. Then go for it.

And do the nickel anti-sieze, and not the last bit, right? Right.

See? I am teh sarmt.

And get the Leslie tool just in case. Although I've heard story how something else can be done... I'll re-read/explore all that later.

Thanks for the help guys. 'Preciated muchly.

Anything or anyone else, don't be shy, all suggestions welcome! I'm in full "informational sponge" mode on this.

05RedGT

I changed my original plugs this past weekend after 50,000 miles. I turned them just enough to loosen them, put carb cleaner in there for 30 minutes, turned then 1/4 turn, let it soak for 15 minutes, turned another 1/4 turn, let it soak about 15 more minutes and then slowly turned them out. None broke luckily. If I felt resistance as I turned I would stop and let them soak a little more. I was relieved that I didn't break any after all the stories I have read about them breaking off.

DPHC13

i have the same sound as you describe. No sound under load and whatnot. I was thinking maybe something to do with the clutch or trans... just a thought. Does your car make a "click" sound when you let your clutch out in neutral? Almost like the throw out bearing or pressure plate clanking. The tensioner thing sounds like something i'm going to look into. I changed the plugs after 60K and all I can say is let them soak, soak, soak!! Don't be in a hurry and you'll be good!

825LTRGT

My car makes the same sound between 2k -3k under acceleration.

Could it be the Charge Motion plates moving around, opening or whatever they do at that RPM?

OneCoolGT

I'm having this same issue but it's not all the time, notice it when the car is at operating temp for a while and under light throttle.. Did the plugs at 90K and has 122K now, was thinking it was crap gas (I use 87) but changed brands and it's still there. Use 89 octane at times but noticed starting issues (owners manual states that too) so been using 87 mostly...would 92 octane cause driveability issues? Dont want to blow money on higher octane for no reason because my car is stock (no tune).