Fuel Knock??

[rsscertified]

hello po - ask ko lang if you also experience this on an automatic car, 1st gear and moving tapos hard press sa gas pedal to accelerate, meron light knock. Pero, kapag smooth press sa gas pedal wala naman knock na maririning.

I asked this kasi yesterday, kasi naririnig ko un kapag ginagawa ko ung hard press. Di ko naman ginagawa un talaga on a regular basis napansin ko lang nung one time kailangan ko lang magaccelerate ng mabilis. i'm using Petron Xtra unleaded (93+ Octane), 3 weeks ago po 10km checkup po nung car, napalitan po ung spark plugs, oil filter, change oil. Last last saturday, nagpakarga po ako ng XCS (95 octane), naririnig ko pa din po ung light knock. From the altis manual, dapat daw di ikabahala ung light knock. Kung heavy knock daw po eh dalhin na sa toyota dealer.

Yesterday also pina-road test ko po ung car. For some strange reason eh wala kaming narinig na knock, pinatakbo nya sa alabang ung car, umabot ng 130km wala po, very smooth.

Ask ko po opinions nyo mga experts, additional knowledge na din for me. Also, need ko nga ba ipacheck pa ito ng todo? May kinalaman po ba un sa pag press sa pedal?

Thanks po in advance

[v6dreamer]

Hopefully, it just about the octane gas are you using. Look in your owners manual and only use the proper octane.

But what you are describing sounds like one of the following; collapsed lifter, worn camshaft, excessive gap in the lower end (rod) bearing. If it has timing chain - that could be yet another source of this type of noise. The good news is if: it's still under warranty, if not $$$$. Go to the dealer(casa) and don't leave until they fix it because noise is minor, they'll start telling you that nothing is wrong hoping that the engine explodes right after the warranty is expired.

[rsscertified]

Hopefully, it just about the octane gas are you using. Look in your owners manual and only use the proper octane.

But what you are describing sounds like one of the following; collapsed lifter, worn camshaft, excessive gap in the lower end (rod) bearing. If it has timing chain - that could be yet another source of this type of noise. The good news is if: it's still under warranty, if not $$$$. Go to the dealer(casa) and don't leave until they fix it because noise is minor, they'll start telling you that nothing is wrong hoping that the engine explodes right after the warranty is expired.

Hi V6dreamer, thanks for your response. I'm really new on cars, so - collapsed lifter/worn camshaft etc I really don't know about those.

Yes this is still under warranty. 1 year pa lang po ito. Actually they have advised me to empty the gas tank before filling it up again then check if the noise is still there.

According po sa manual, 91 octane or higher is recommended. Since I got it, I'm using xtra unleaded from Petron which is 93+ octane. just recently I used XCS since they said it's much better for mileage.

This morning, while I drive to office, I'm trying to check kung merong noise pa din, binalik ko sa smooth press sa pedal ng gas, seems to be fine naman. baka na sa pag biglang apak ng gas medyo may light knock.

[v6dreamer]

What is XCS?
Proper maintenance in your car is always your best bet of better milage and they way you drive....nothing else. The rest......use at your own risk.

[niky]

Might have been bum gas.

No brand new car should knock on sudden prods of the throttle. With electronic fuel injection and O2 sensor mediated fuel trimming, it's next to impossible.

[rsscertified]

What is XCS?
Proper maintenance in your car is always your best bet of better milage and they way you drive....nothing else. The rest......use at your own risk.

Hi V6Dreamer, it's a name for unleaded gas here in Manila that has 95 RON
http://www.petron.com/fueljourneys/f...fuels-pxcs.asp

Might have been bum gas.

No brand new car should knock on sudden prods of the throttle. With electronic fuel injection and O2 sensor mediated fuel trimming, it's next to impossible.

Hi Niky - thanks for your response. May I ask - what do you mean with bum gas? I apologize, I'm really new with engines.. What should I do? Do I need to change to a new fuel? Thanks!

[normanenoza]

did they check if ok pa yung knock sensor mo. a busted knock sensor will never trigger the check engine light. IMHO, using gas with higher octane rating than the recommended is just a waste of money. remember this, it is already the recommended gas specified in the manual and not the minimum required. your engine will just utilize the same amount of heat irregardless of the octane rating of the gas.