Noise On Acceleration (On Gear) - Feels Like Around The Exhaust Or Cat?

[INSANITI]

Hi All,

I hear this noise much like some rattle in cylinder on acceleration - or like a pinging noise coming from under the car around (say mid) where the CAT and exhaust I think joins.

have you heard this on your car? its more on medium acceleration rather than hard acceleration.

it doesn't have on gear change only when, you suddenly see a gap and put your foot down to catch up.

like I said like a pinging noise but not quite if it makes sense.

I have a feeling it could be my CATALYCTIC since ive done around 66k kms.

I have a 2005 V35 coupe. its due for service so I will mention it to them but it would be great if someone can give me pointers.

sorry don't really know much about what is under the car as I normally rely on the service to find these things.

What are you thoughts?

[zoomzoom]

Run your hand all around the exhaust pipe and see if its close to touching anything. An exhaust touching the body can cause some wild in-car noises.

[Ben C34]

It could be pinging. As you mentioned a couple of times

What fuel are you using?

[INSANITI]

have only used BP98 or shell 98 or Caltex 98 (try to avoid this as somehow my fuel consumption on Caltex aint very good).

Its 5speed automatic ? can it ping on an auto? sounds like its pinging but doesn't feel like it is.

I have a catback exhaust so I doubt its from there well doesn't feel like its there.

I sorta also sound like rattling in a cylinder some loose particles of some sore.

[Ben C34]

Sounds like you don't actually know what pinging is.

The type if trans makes no difference and there is no feeling associated with it.

Just the exact rattle type noise you have described, under the conditions you described.

Did it just start happening since last tank fill?

A mate accidently filled up with 91 octane and his car pinged. When you are sleepu you can do silly things.

[INSANITI]

ever since I bought my car 3yrs ago when it had 35k kms I have always used 98. That sound has always been there. not gotten worse or better.

I just didn't bother with it. I figured i'll mention it this time on my next warranty service.

I was hoping its not like the transmission or anything like that.

[Ben C34]

That's weird then.

[Nightcrawler]

Sounds to me like the innards of one of your cat converters has come loose - makes a noise like this at certain revs, and not at others. Get the workshop that does your next service to pull them off and shake them around to see if they rattle. It also could be one of your many heat shields come slightly loose and rattles at certain revs.

[PN-Mad]

+1 for heat shields coming loose. They are spot welded together and combination of rust and vibration can break them. Just get it up in the air, and find out where it's coming from.

[INSANITI]

oh btw I hear it more when the exhaust system is cold too. like first thing in the morning when I take off mid-acceleration... felt like some little stones (low pitch) moving around a cylinder....

[Ben C34]

Just for reference that is exactly what pinging, detonation or knock sounds like.

Might just be a loose stone guard.

[Hertz Donut]

I have a similar noise in my Stagea, I'm pretty sure it's just a loose heat shield or possibly the outer wall of the exhaust corroding away and rattling against the inner lining. Not sure if the V35s have a twin-wall exhaust too though. Mine is only noticeable under light-moderate acceleration and always around 2000-2500rpm, suggesting it's a harmonic frequency causing a vibration.

I haven't had much time to check everything thoroughly, I pulled away some of the outer wall but it didn't go away. OHNOES!! NEW EXZORTS TIME!!

[INSANITI]

ok just did my service. I barely couldn't here it. I am assuming its the oil that they used? they went from halvoline to valvoline 10/30. so im guessing the car was pinging.

My question now is every couple of thousand kms' i see my oil goes to 3/4 full. Do i need to top this up? i did in the past on what is the recommended grade oil and i used shell. Do you think since i topped it up its causing the pinging on the car?