Alto: Constant Knocking

[ScarySkulls]

Car:- 07 Alto LXi
Mileage:- 15k kms

Just noticed when I took out car to highway this weekend. Constant knocking whenever accelerator is depressed. Especially after 80. Had to continue by journey at 60-70 till I reached my destination.
Car doesnt knock much when not fully warmed up. But starts doing it after a few kilometres.
Will knock in 1st gear also on sudden acceleration. Sometime if you pump the throttle hard while engine is idling, you will feel a faint knock sometimes.

Car was serviced one month ago. Injectors were cleaned.
I always use IOC xtra premium 91octane.
Tanked up before this drive. Fuel Pump is the same from where I always fill.

Any possible causes?


P.S.>> When I drive alone, knocking is reduced. But goes up to alarming levels when friends/family travelling alongwith.

[abhibh]

Originally Posted by ScarySkulls

Car:- 07 Alto LXi
Mileage:- 15k kms

Just noticed when I took out car to highway this weekend. Constant knocking whenever accelerator is depressed. Especially after 80. Had to continue by journey at 60-70 till I reached my destination.
Car doesnt knock much when not fully warmed up. But starts doing it after a few kilometres.
Will knock in 1st gear also on sudden acceleration. Sometime if you pump the throttle hard while engine is idling, you will feel a faint knock sometimes.

Car was serviced one month ago. Injectors were cleaned.
I always use IOC xtra premium 91octane.
Tanked up before this drive. Fuel Pump is the same from where I always fill.

Any possible causes?


P.S.>> When I drive alone, knocking is reduced. But goes up to alarming levels when friends/family travelling alongwith.

There you go u have the answer my bro. XTRA premium petrols. Not at all good for Alto engine. Even my cousin and a friend facing same problem as they use premium fuel. Shifted to the normal and it has reduced upto great extent.

I could be wrong here but this is what i have observed personally.

[mithun]

The knocking is not related with Xtra Premium. I'm using Xtra Premium for the last 40,000 KMS on my Alto. The drive is silky smooth.

Change the pump from where you're filling.

[ScarySkulls]

Why not premium fuels? What's wrong with them. My Karizma, almost refuses to run on anything less than 91octane. My earlier 800 also felt better on this fuel.

Anyways, the pump is one of the most reputed one here. Still, I'll try changing as soon as this tank finishes. So fuel is the culprit then? (Seems a bit unlikely though seeing the reputation of the pump...)

[tsk1979]

check the timing if Fuel is not the culprit. This is the most common cause.
And get fuel filled from the IOC on ferozpur road just after the Canal bridge(Opposite Verka)

[srijit]

Same thing happened to me after a regular service. Took it back and the guys said that they retuned it.

[ScarySkulls]

@ TSK - Yes. Same petrol pump. How come timing? The base plate needs to be rotated too to adjust timing in a fuel injected car?

@ Srijit- Details please. How come "retuned" ? I dont think there is an option to play around with maps or stuff, neither do I see any wide band O2 sensor with them....

[vid6639]

Get your spark plugs cleaned once again as well just in case.

[lohithrao]

Switch to regular fuel, am sure this issue is related to premium fuel.

[ported_head]

Does Alto come with DIS or distributor? Does it come equipped with EGR?

[sukheshkumar]

I think it is Premium Petrol which is the reason for this knocking.
Earlier, sulphur was added as an additive to induce anti knocking properties.
With the advent of Green marketing, the same additive is considered as an impurity and premium gasolenes take this out of Gasolene.

Reduction of knocking is done by car makers. I do not know whether alto manual prescribes Premium Gasolene. Check this aspect.

This knocking is not heard in cities and are heard only on Highways because of ambient noise in the city.

Sukhesh Kumar BR

[rks]

Originally Posted by sukheshkumar

I think it is Premium Petrol which is the reason for this knocking.
Earlier, sulphur was added as an additive to induce anti knocking properties.
With the advent of Green marketing, the same additive is considered as an impurity and premium gasolenes take this out of Gasolene.

Reduction of knocking is done by car makers. I do not know whether alto manual prescribes Premium Gasolene.

I thought it was lead that had the anti-knock properties? All fuel supplied today is unleaded. Instead of lead the premium fuels have other additives that effectively increase the peformance of the engine and should help in reducing knocking unless the Alto's ECU is unable to adjust to these premium fuels. I have been using Speed 97 for some time now in my Santro and the pickup is noticeably better.

Edit: The knocking could also be due to some blockage in the fuel supply,and the car may be running a lean mixture. Check fuel filter, fuel pump, fuel lines and injectors in addition to the ignition timing. Fuel quality could also be the culprit, as pointed out by others.

[srijit]

Originally Posted by ScarySkulls

@ Srijit- Details please. How come "retuned" ? I dont think there is an option to play around with maps or stuff, neither do I see any wide band O2 sensor with them....

I guess that was their way of saying that they had fixed the problem. You know, to make it sound that they had done more work Or maybe, he mentioned timing, which I misheard/mistook for tuning.
The info from the service bill (free) is:

• Spark Plug (All) R&R
• Camshaft - Timing Belt

These were the things they did, and it reduced the knocking. I use only Premium petrol, so that doesnt come into play yet. Alto has run about 15,000 Kms in 2 years.

Hope this helps

[ScarySkulls]

Originally Posted by ported_head

Does Alto come with DIS or distributor? Does it come equipped with EGR?

I remember the Baleno being a DDIS. Cant confirm about the Alto, right now.
Not sure about the EGR too. Will check and get back to you.


Thanks guys. I think I'll observe this tank of fuel to see. Currently very VERY frustrated. Put in regular 87octane to check if what difference it makes to my Bike. It's refusing to accept anything more than 30% throttle without knocking.
Extremely pissed off right now. Car is knocking after refill. Bike is knocking after filling regular 87octane from the other most reputed pump in town.. Scooter is grounded because I forgot to renew insurance on that.


Damn!!!!!

[amit_mechengg]

get your valve tappet clearances checked. secondly ask them to check the settings of ECU by using tech2. thirdly ask them to check the timing in front of you. they will show you a white flashing light which has to match perfectly with the marking near the pulley of the alternator.
at the last one sincere advice. stop using premium fuel for low compression engine like alto. i have suffered a lot due to this which i have discussed in other threads. stick to normal unleaded fuel only from a good reputed fuel station.