Cadillac Owners Forum banner

1 - 10 of 10 Posts

·
Registered
2009 - CTS-V
Joined
·
17 Posts
Discussion Starter #1
I've had my 09 CTS-V for a few weeks now and I still feel like a kid with a new toy.

While driving the car home from the dealer I noticed a knocking during a moderate acceleration. The next day I called the dealer and spoke to salesman about the noise, turns out they only use like 87 octane in their Company fuel tank so that's what they put in the car. A few days later it was time for it's first fill up and it got filled with Super Unleaded (93 octane I beleive). It still has this knocking when you step into it but I can't tell if this is a fuel knock or a knocking coming from the top end. Anyone else have any experiance with this. I really hate the thoughts of having the dealer start monkying around with the car, it has just turned 1000 miles.

I also really dislike the way the car shifts into 6th gear at such low speeds and then you really need to push the throttle to get it to kick down, the shifting kind of reminds me of the tranny's in the big G.M.'s of the late 70's shifting up/down/up/down.

I see Wait4me has some tuning equipment.... anyone tried it yet?

Thanks,

Glenn
 

·
Registered
2009 CTS-V
Joined
·
98 Posts
Ummm , I heard what sounded like a knocking sound eminating from the top speaker in the center atop of the dash . I got concerned , it happened when I would accelerate from a stop . So I got concerned and refilled my tank with 91 shell and suddenly the knock stopped a few days then came back a few times afterwords . It's not consistant but my dealer said he put in 91 octane for the fill up , so I guess this weird knock - like sound , is normal .

CADYSHAK
 

·
Registered
Owned 3 V's, now driving a Wrangler and XT5
Joined
·
2,574 Posts
I have mine in for oil change today and asked them to look at the same thing. When cold it makes a ticking sound up near the supercharger, when acclerating sometimes it makes more of a knocking sound.

It could possibly be the fuel injectors I was told, I'll let you know what I find out.
 

·
Registered
2011 GTR
Joined
·
1,026 Posts
Ticking sound at idle is normal. Those are the fuel injectors, but under acceleration you can't hear it because the motor is getting louder. If you hear a noise that sounds like "marbles in a can" that is what engine knock sounds like. That is not normal and on a FI car, that can destroy a motor quickly. This can come from poor quality fuel, etc. As for the poster that had 87 octane in his original tank, it will take several fill ups with 93 to get the octane back up. I would suggest a quality octane booster. Also, hot weather makes the car succeptable to more knock. Many many variables. If it doesn't sound right, keep taking it the dealer until it's right.

Also, the wait4me tune is awesome and really makes a difference in the way the auto shifts. Also makes a difference in the power of the motor too. For the price of his tuner, it's a "no brainer" in my book.

Mark
 

·
Registered
2009 CTS-V
Joined
·
98 Posts
Question : when would the "knocking sounds" come in around ? I had something similar but doesn't happen as often now but occasionally it does . I am using 91 shell and as far as I know the dealer told me he put in 91 petrocan gas when I took delivery . Thanks in advance in your replies . CADYSHAK

P.S -During the break - in period on semi hard acceleration the knocking never happend , only when lightly accelerating from a stop .
 

·
Registered
2009 - CTS-V
Joined
·
17 Posts
Discussion Starter #6
The knocking in mine seems to come and go as well, I know if I take it to the dealer it won't do it. It seems to happen at moderate throttle.:bighead:
 

·
Registered
11v,2 09 v's,2 05 v's,5 GTM supercars,viper,volt,2012 karma
Joined
·
2,997 Posts
There is a tsb for the marble sound at idle. It is the Dampner in the supercharger between the snout and blower rotor assembly. It isnt the injectors making the knock noise.
That noise goes away with a solid dampner isolator. They say it is for torsional vibration in the rotor pack. Mine is eating up the unhardened shaft inside the blower where the spring rides on it. Pretty dumb and i can see a failure happening before my 100,000 mark. As with 2000 miles it is a NOTICABLE chunk missing.
 

·
Registered
2011 GTR
Joined
·
1,026 Posts
So, in order for a TSB to be completed for this, what needs to happen and what does the dealer need to know. I know TSB's are only performed if customer complains about something and there is a TSB for it.

As for the part throttle knocking noise, it very well could be engine knock. It is based on load on the engine. For example, flooring the car in 5th or 6th gear and not downshifting at low speeds would put a great load on the engine and the knocking could occur if poor fuel is used. Just because the tank says 91 octane, doesn't mean it is. I'm not sure of the quality of shell gas either. Some guys on the corvetteforum were talking about it I think.

Thanks,
Mark
 

·
Premium Member
2009 CTS-V Black/Black, manual
Joined
·
1,371 Posts
^^^ I thought I read somewhere that the ECM will try to prevent knock by de-tuning the motor when knocking is detected. Is there a knock sensor on the v2? I know my old Toyota Supra Turbo had one ...

Rob
 
1 - 10 of 10 Posts
Top