View Full Version : Scratchy sound when driving uphill

EXceptional Woman
04-08-2008, 10:22 AM
Hi everyone,

Occasionally I have been hearing a scratchy ticking sound when going up steep hills. I really don't know how else to describe the sound. It happens when I accelerate hard to get up the hill, but not so much if I just keep the gas pedal steady. I hear this sound all the time on my 8-yr old Accord, but wouldn't expect it with my nice new baby. Has anyone else heard this? Maybe I am imagining it since I always heard it with my old car.

04-08-2008, 11:09 AM
It could be what is referred to as "engine ping".

I think the manual says something about it...specifically if you're driving hard up a hill.

04-08-2008, 11:54 AM
What kind octane fuel are you using in your vehicle?

EXceptional Woman
04-08-2008, 12:46 PM
I'm using 93. I'll have to check out the manual, thanks!

04-08-2008, 02:26 PM
You may also want to try out different gas stations.

EXceptional Woman
04-08-2008, 05:17 PM
Thanks everyone. Do you mind if I ask what makes you think it is gas-related? I always go to a very busy, clean Sunoco. Should be good stuff, no?

04-08-2008, 06:54 PM
Definitely sounds like pinging to me, though you could record it and upload it so we can hear :). Does this happen when you start up the hill (the engine at low rpms) or the whole way up the hill? You might try leaving the car in first gear as you ascend the hill, to see if the noise gets worse or better.

Better yet, next time you take the EX to the dealer, take them for a test drive (assuming there's a hill nearby) and have them listen to it.

As for gas stations, there are sooo many variables. Best to run your tank close to empty and then try another station to see if the problem disappears.


04-08-2008, 07:32 PM
Your choice of 93 form a name brand busy station should usually preclude a pinging problem, but like others said you can never be sure.

I like the recommendation of duplicating the condition for a dealer tech, he will be able to tell if it is pinging ( like it "sounds" to us) or something else.
Another way to tell if its pinging have it at about 1 /3 rd tank and add a bottle of octane booster to it ( The stuff that says MMT on the back as ingredient is the best)

Then drive that hill, if the noise doesnt happen now you almost certaionly have pinging.

In any event its best to get this figured out soon.


EXceptional Woman
04-09-2008, 09:35 AM
Thanks. I've never heard of this pinging before. Do you know what causes it? And why it would happen on a hill? So strange.

04-09-2008, 11:36 AM
Pinging is the fuel mixture pre igniting.
This most commonly happens under laod.
Preferably it doenst happen at all a sit can damage the engine severely.

Hopefully it is something else, or if it is this, you ID it quickly and dealer can address.


04-09-2008, 07:58 PM
Octane rating tips
Using unleaded gasoline with an octane rating
lower than recommended above can cause persistent,
heavy spark knock. (Spark knock is a
metallic rapping noise.) If severe, this can lead
to engine damage. If you detect a persistent
heavy spark knock even when using gasoline of
the stated octane rating, or if you hear steady
spark knock while holding a steady speed on
level roads, have an INFINITI dealer correct the
condition. Failure to correct the condition is misuse
of the vehicle, for which INFINITI is not responsible.
Incorrect ignition timing will result in knocking,
after-run or overheating. This in turn may cause
excessive fuel consumption or damage to the
engine. If any of the above symptoms are
encountered, have your vehicle checked at an
INFINITI dealer or other competent service facility.
However, now and then you may notice light
spark knock for a short time while accelerating
or driving up hills. This is no cause for concern,
because you get the greatest fuel benefit when
there is light spark knock for a short time under
heavy engine load.
Hope this helps.

EXceptional Woman
04-09-2008, 10:30 PM
Thank you, ralt and Palmer. This info is extremely helpful. So far I have only noticed it on hills, but am still going to have it checked out and will report back. As for my Honda, I hear that all the time and have for a long time. I just figured it's old, but had no idea I was doing permanent damage! Woah. I wonder if there is something with the gas we buy because we always use the recommended octane (and my Honda is just regular anyway).

04-10-2008, 07:33 AM

Keep in mind this is only an interhnet diagnosis based on descriptions are our interpretattion of such.

It <could> have a differfent cause.

This usually happens on older vehicles so it would be a bit unusual for youre EX to show it but the syumtpoms as described do seem to point towards this.

Recently I heard of some Infiniti showing it when new , as the quest for horsepower and efficiency forces manyfacturere toi raise compression this is a more common occurenbce in newer vehicles but still rare.

I am curious what your dealer reps will say.


04-11-2008, 08:03 AM
OK...I heard 'the noise' this morning. It definitely was not an engine knocking noise. Believe me, after 35 years of driving, I know what that noise sounds like. I heard it just a brief moment when eccelerating up an incline. It sounded more 'scratchy' than like a ping...almost like a grinding/scratchy noise, and as best I could tell, it seemed to be coming from the left front wheel area...or lower engine bay. I remember my first G35 had a horrible grinding noise that ultimately turned out to be an A/C unit issue that plaqued the first production grouping of the G. This was not that though as I did not have the A/C on. I could not reproduce the noise afte I first heard it. It's not very hilly around where I live, but I will report back if I hear anything else. I have not noted any noted change in performance.

04-11-2008, 09:39 PM
If it's a grinding/scratchy noise, I would definitely stop by the dealer to have it checked out or at least call them to alert them of a potential problem, as this can help them track down nascent problems.

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04-13-2008, 06:02 PM
I haven't heard it again. And when I did hear it, it lasted all of 2 seconds. There is no point in calling the dealer. They won't and can't do anything until they can reproduce the event themselves.

04-13-2008, 11:07 PM
I haven't heard it again. And when I did hear it, it lasted all of 2 seconds. There is no point in calling the dealer. They won't and can't do anything until they can reproduce the event themselves.

I called my dealer about a strange sound coming from my M, even though, at the time, it was not reproducible. The next day, a factory rep called me to discuss it. A week later, they figured out what the problem was (misadjusted parking brake, causing a light rattling sound) and fixed my car and others.

But, YDMV.


EXceptional Woman
04-14-2008, 10:27 AM
I am still hearing it any time I accelerate hard up a hill, even not very steep ones. I am going to test it out at different RPMs to see if I notice a pattern. I am taking it in on Wednesday so I will follow-up and let you know what they say. When I called they didn't seem too concerned.

04-29-2008, 03:15 PM
Any update on this? This morning I twice had an odd sound on hard acceleration, definately not pinging.

EXceptional Woman
04-29-2008, 03:27 PM
My dealer told me to bring it in anytime, no need for an appt. I first tried a different brand of gas (from Sunoco to Mobil) and I haven't noticed it since so I never went. I am continuing to keep an ear out. I noticed it mostly in the 2,500 to 3,000 RPM range, going about 40 mph uphill. How about you?