Noisy injectors (?) at 3500RPM

[MrDinkleman]

I've been noticing two issues, lately:


1. Once a month or so, while cruising or accelerating on the freeway between 3k and 4k RPM, my engine will get really noisy. Sounds like the injectors are rattling, usually. Although, sometimes it makes a shearing noise. When it starts to happen, I step on the clutch to coast and blip/rev the engine for about 10 seconds. The noise then goes away.


I haven't taken it to the dealer because I don't want to get annoyed when they tell me they can't replicate the noise. I can't record it because it happens when I am doing 70+MPH or when I am trying to get to 70+MPH


Has anyone else here have or heard of the same symptoms and what did you do? Is this a known service bulleting or warranty issue?


2. A lot of times when I am upshifting, I will here a rattle or two when I step on the gas as I let the clutch out. I am guessing this detonation?


TIA

[Ultramaroon]

While it's making the noise, tap on the clutch pedal a little. Not enough to disengage it, just a tap. Don't do anything else.

Does it affect the noise?

[radroach]

@MrDinkleman what I believe you're hearing is the VVT changeover. It's noisy. Sometimes to the point you'll hear absolute rattling during it if you're in the wrong throttle/load scenario.

[ame="https://www.youtube.com/watch?v=9t4QtTmfBsA"]Vortech FRS VVT Angle Comparison | P2 - YouTube[/ame]

My guess to why we have a sound generator on our cars it to cover that sound with intake note instead. This engine just has a lot of valvetrain noise, along with the clicking injectors, and lots of other stuff that makes noise constantly, and these noises are way more noticeable to the driver in a normal daily driving environment than in a track scenario.

[humfrz]

Originally Posted by MrDinkleman

I've been noticing two issues, lately:


1. Once a month or so, while cruising or accelerating on the freeway between 3k and 4k RPM, my engine will get really noisy. Sounds like the injectors are rattling, usually. Although, sometimes it makes a shearing noise. When it starts to happen, I step on the clutch to coast and blip/rev the engine for about 10 seconds. The noise then goes away.


TIA

"Once a month or so" ....... I wouldn't worry about it .......

Have you changed brands of gas lately .. ??


humfrz

[MrDinkleman]

Thanks to everyone who's replied so far. I didn't have my password so I couldn't respond earlier:


I'll try tapping the clutch pedal next time it happens and see if it changes anything.


I have almost exclusively used Chevron 91 from the same station ever since I found it made the crickets go away. I have occasionally used Chevron from other stations when forced to such as when I went to Las Vegas.


I do hope it is nothing more serious than the VVT crossover thing. I was just wondering if anyone else has experienced it, too...

[Tcoat]

Originally Posted by radroach

@MrDinkleman what I believe you're hearing is the VVT changeover. It's noisy. Sometimes to the point you'll hear absolute rattling during it if you're in the wrong throttle/load scenario.

My guess to why we have a sound generator on our cars it to cover that sound with intake note instead. This engine just has a lot of valvetrain noise, along with the clicking injectors, and lots of other stuff that makes noise constantly, and these noises are way more noticeable to the driver in a normal daily driving environment than in a track scenario.

This^ I have had it happen a couple of times when I hit the perfect storm of backing off the throttle at higher speeds. Scared the crap out of me the first time since it sounded just like an old V8 that was going to blow a valve at any second. The second time it happened I just gave it a touch of gas and it leveled out and that was when I guessed it was just the changeover happening under those particular conditions.

[radroach]

I've twice noticed VVT rattle after long trips getting off the highway, 3rd gear 35 mph had a noticeable rattle on throttle. Certain conditions, may have been low on oil though my guess.

[Ultramaroon]

Tcoat, radroach, I'd be willing to bet money it was the clutch master cyl. spring. Not to get into it because I tend to get on these kicks where I'm sure everyone's experience is the same as mine but keep this thread in mind.

For me, it has only happened in the peak of the summer heat and very intermittently. It is the most god awful sound for sure but after discovering the source, I just press the clutch pedal a quarter inch or so just to jiggle it and it immediately stops.

[Tcoat]

Originally Posted by Ultramaroon

Tcoat, radroach, I'd be willing to bet money it was the clutch master cyl. spring. Not to get into it because I tend to get on these kicks where I'm sure everyone's experience is the same as mine but keep this thread in mind.

For me, it has only happened in the peak of the summer heat and very intermittently. It is the most god awful sound for sure but after discovering the source, I just press the clutch pedal a quarter inch or so just to jiggle it and it immediately stops.

When it comes to describing sounds in print there are 1,000 things it could be. I have zero doubt that what I heard under very similar circumstances was the injectors.
We sort of play ourselves whenever we try to guess based upon the little info and basic descriptions that we have on these threads even at the best of times. It is better that there are more options as to the cause put out there though since it gives far better odds that the true issue will be identified. Somebody could spend a pile of time chasing down a rattling clutch spring just to find out that it was something totally different. There really can be no absolute "this is your problem" based upon the info at hand.

[Ultramaroon]

Originally Posted by Tcoat

When it comes to describing sounds in print there are 1,000 things it could be.

Yup. Guilty.

But do try it next time you hear the sound.

[MrDinkleman]

Another thanks to everyone.


Ugh. I hate intermittent problems. Now I am actually hoping it happens again, soon, so that I can try the clutch pedal advice...

[strat61caster]

+1 on VVT noise for #1, I hear it all the time.

#2 may just be the clutch/tranny doing it's job as you actuate it, there's like a piece of plastic then sheet metal between your leg and the transmission and that's it, you hear just about everything.