Terrible knocking problem, help!

[eejart]

Hi all sifus.. Last June I had my clutch replaced. On the day I picked the car up the mech brought me around just to test the car, and I notice at times there's a very mild chatter but dunno exactly when will it happen. Until all the petrol-itics happen in our country, as I learn more, this chatter is apparently the sound of engine knocking!

So here's my problem, since that time, it's been getting easier and easier for knocking to occur. Last time when I'm inappropriately geared, I can accelerate (at least half throttle) and the engine won't knock, but now during a hot afternoon, even if I attempt to floor from 2nd gear also will knock a bit before perfect combustion. Why is this happening?? I can't even overtake a car without having a short knock. I know it's unhealthy for the engine so I hope to solve this problem quick :(

Thanks all!

 

[jameswwt]

Been thru yr Fear but thanks to some members advise,i've learned to live with it...I always check the knocking level thru my ECU Commander...
When hot day,knock will definitely higher and other than that should check with yr mech, tuner or friends (seek advise) on the afr,fpr pressure,etc...
Just my friendly experience.

 

[flanker c]

Hi all sifus.. Last June I had my clutch replaced. On the day I picked the car up the mech brought me around just to test the car, and I notice at times there's a very mild chatter but dunno exactly when will it happen. Until all the petrol-itics happen in our country, as I learn more, this chatter is apparently the sound of engine knocking!

So here's my problem, since that time, it's been getting easier and easier for knocking to occur. Last time when I'm inappropriately geared, I can accelerate (at least half throttle) and the engine won't knock, but now during a hot afternoon, even if I attempt to floor from 2nd gear also will knock a bit before perfect combustion. Why is this happening?? I can't even overtake a car without having a short knock. I know it's unhealthy for the engine so I hope to solve this problem quick :(

Thanks all!

knock may occur on 4g93t:

Ron 95 -knock
AFR lean -knock
too Heat - knock
ignition too advan -knock

 

[eejart]

Been thru yr Fear but thanks to some members advise,i've learned to live with it...I always check the knocking level thru my ECU Commander...
When hot day,knock will definitely higher and other than that should check with yr mech, tuner or friends (seek advise) on the afr,fpr pressure,etc...
Just my friendly experience.

so sifu, you mean to say this is a normal problem and will not cause detonation? my PFC didnt come with a commander unfortunately so cannot check :( I heard one of the causes could be a malfunctioning fuel pump, any ideas how I can diagnose this?

knock may occur on 4g93t:

Ron 95 -knock
AFR lean -knock
too Heat - knock
ignition too advan -knock

out of all this only the heat factor affects me. I use 97 and my AFR is alright after tuning. ignition too advan means what bro?

 

[pink cefi]

i suppose ignition too advan as stated by flanker c is ur ignition timing set too advanced by ur tuner. a lean a/f ratio = higher engine temperature so both are related. u could always talk to ur tuner for advice as he knows ur car best. and are u sure its engine knocking? wat clutch did u change to by the way? as u said slight chatter, izzit ur clutch tat's making the chatter? :D

 

[eejart]

but I drove the car for a year after the tuner did his work, no chatter at all. the problem only started after I changed clutches (OEM to OEM).. the sound only comes when I accelerate quickly at low or average speeds and will disappear when the car has picked up momentum..

also, the chatter doesn't come when I rev during idle, even during a very hot afternoon..

I remember the tuner telling me my car is running stoich because I requested for balanced FC and power, and the figure shown on his laptop was indeed around 11 to 12. never done any modifications after that, but perhaps the AFR has changed since then due to the nature of engines. maybe I will stop by another workshop with a PFC tuner to check on this, as I don't visit the tuner that initially tuned my car anymore :)

 

[dawg]

I'm assuming the chatter sound maybe be from the tensioner instead of knocking. If your A/F ratio is 11-12 you are on the rich side. Stoich is 14.7 and lean would be above 14.7 ...

Evos tend to have this problem with our tensioner making a chattering sound at low rpms like 1,000 to 2000 rpm range and it will be gone.

When you change your clutch, did the mechanic remove your tensioner and tighten it back? If he touched the tensioner, then its highly probably that its the culprit bcos you need certain force applied to tighten the tensioner. Too tight or not tight enough will make it make chattering sound.