Why is my brand new car KNOCKING?

[ecko51]

Man I hope nothing serious is wrong. I just put the frist tank of gas in it on Sunday and now today it sounds like it has a knock at idle, but goes away when it revs up.
I put 89 octane in it because thats what the dealer filled it w/ when I bought it.
Could I have gotten bad gas?
Or is it a sign of something much worse?
I will call them tommorow and get it in.

 

[sieben]

more info???

 

[nycstang37]

are you sure the dealer used 89? b/c the car is supposed to run on 87.

 

[JTGrant]

is it a knock or is it fuel injectors?

 

[ecko51]

It's more than just a ticking that the injecters woul make.

 

[Szlachcic]

Was your air conditioner on? I believe their is a solenoid or something that makes a ticking or knocking noise every so often when the air conditioner is on. If that is it you get used to it after a while or you can just get a louder exhaust and you won't notice it at all, lol.

 

[ecko51]

Does the defroster use the AC compressor?
If so you may be on to something.

 

[Spdfreak]

Because you won't let it in?

Sorry, I couldn't resist.

 

[nycstang37]

Because you won't let it in?

Sorry, I couldn't resist.

why am i the only one who got that

 

[bigcat]

Does the defroster use the AC compressor?
If so you may be on to something.

yes, the A/C comes on for the defrost setting.

 

[95snoozer]

i dont care how bad your gas is, there shouldnt be knocking with no load at idle

 

[NY05GT4ME]

Because you won't let it in?

Sorry, I couldn't resist.

Who's there?

 

[NK06Roush]

I just bought a week ago a stage 2 roush mustang. The dealer there told me that I can put 87-93 octane in there no problem. He said if you want to put in 93, the computer is tuned to recognize this and you will pick an extra 5 HP. So far I have gone through almost 3 tanks of gas running 93 octane and have no problems.

 

[dmaxstang]

Who's there?

MustangBeats!!!

MustangBeats Who???

Everybody you idiot!!!

Read the manual, it is ok and normal for the car to knock just a bit, but when it becomes abnormally loud you should use your 3/36k warranty. Turn the knob on the right all the way up to the ( 0 ) and see if it knocks still. Then go like hell because the car just got 50% of its power back. HAHA Congrats though on the new ride. Oh yeah, and the raddles that will start in about 4k miles are normal also, have fun.:SNSign:

 

[Razinhell]

I just bought a week ago a stage 2 roush mustang. The dealer there told me that I can put 87-93 octane in there no problem. He said if you want to put in 93, the computer is tuned to recognize this and you will pick an extra 5 HP. So far I have gone through almost 3 tanks of gas running 93 octane and have no problems.

Uh...no. Your car cannot tell what octane the fuel is. What it can tell is that it there is predetonation due to low octane exploding before the spark plug ignites the fuel. In other words higher octance just means it has more chemicals in it to resist the predetonation. You won't gain more horsepower on a higher octance unless your car is already having problems with the lower octance. That is if you have crappy 87 octance gas in your area then your gonna get poor performance. If you move to the next level, such as 89, and there is no more knocking then you are going to get more performance. The only time you will get more performance from a specific octane is if you tune the car to utilize the fuel. Even then unless your running a Forced Induction or other power adders there is no reason for a higher octance unless your area just has poor gas. Now that they are adding ethanol to a lot of fuels there is always a chance that your car won't like the lowest octane. Remember that octane is an average of the Motor and Research method so you may get the low end of the average they may even round up.

 

[FLY2kGT]

That comment about the 87 octane gas is great. This thread has now turned into a "get higher octane gas for more performance" thread. Just do a search and some research and you'll find that the ONLY reason to use higher octane fuel is to prevent predetonation. Using 89 or 92 when your vehicle was designed for 87 will NOT INCREASE PERFORMANCE! I've seen this soooo many times over the years and it still baffles me that with today ability to research, people are still confused. I better stop here before I turn this into an essay. Just go research please.

 

[CPman]

It could be a cam phaser noise if the noise goes away above idle. I believe there is a TSB covering that condition. Check it out.

 

[JTGrant]

actually some of the new cars (Honda accord) advance the timing until the knock sensors sense knock and the ecu will retard the timing a few degrees. I don't know if our cars do this. I know that we have knock sensors. if you were to put 93 octane or a higher octane fuel than what is in there fromt the factory it will pick up more power if the car had this.

 

[ecko51]

Yes it does go away when I get on the pedal even a little.