2010 1.8 Altis pinging/knocking under load or acceleration

[shorty_bari]

aoa everyone.

so i have a 1.8L 2010 Altis A/T. Ever since i have the car, it has been making an obvious pinging or knocking noise when i accelerate. If i floor the pedal, it goes away (or atleast cannot be heard under high revs). but the noise increases or is easily made when more people sit in the car.

Ive just got iridium plugs
changed coils (no difference tbh)
changed oil 1k kms ago (switched from Zic 10-40 to Castrol Magnatec 10-40)
extracted and cleaned the VVTI solenoid (with carb cleaner)
cleaned the MAF sensor
cleaned the purge valve/canister
Cleaned the intake with carb cleaner
got the exhaust checked (the guy says catalytic converter seems fine)

what else should i do before accepting that the engine is a gone-case???

google says to check the pcv valve too. but im kinda tired now of checking everything and not making a difference.

the engine is over 220k now. (but no obvious sign of bad performance in my opinion)

need a good suggestion please.

Thanks

[hash4u]

tried switching fuel station or mixing hi octane a bit?

[shorty_bari]

I've changed fuel stations several times. My regular fuel station is PSO at Girja chowk cantt. And I get full tank of hi octane quite alot , randomly. But no difference when I'm on hi octane

[shorty_bari]

Experts. Please help.

My random (additional) guesses go towards carbon build up in cylinders; timing is off (what could the parts in question be?) ; fuel system lag maybe?

please dont ask why the above Just random guess after going through hundreds of videos on youtube.

[shorty_bari]

Aoa. Experts, c'mon. there has to be some experienced advice on this?

Also, important update : (I forgot to mention earlier) some times this issue completely disappears. Like last night when i drove back from work to home, the noise was gone completely and the car felt faster and more responsive as well. It stays like that through out that specific trip from point a to b.

This random disappearance occurs roughly twice or thrice every month. This means something is faulty but not completely broken yet.

[UAHMAD]

Can be crankshaft noise due to worn out main or connecting rod bearings.

I have seen this problem in another Altis Corolla of same year model.

[shorty_bari]

actually im a little scared to even consider possible faults like this

Do you think this is possible , considering that the noise completely disappears once in a while (with increased overall engine response during that trip) ??

Also do you think there could be an issue with the chain tensioner or even "knock sensor" ?

Honestly, this looks like an electronics' issue . i dont know

[UAHMAD]

I also hope and pray that there is no bigger issue related to crankshaft due to bearings etc.

Timing chain tensioner gives noise mostly at cold start since the chain is loose inside, and this sound reduces as the engine warms up. Please see if that's the case.

Knock sensor failure leads to check engine light. And may also result in loss of power.

In any case, please consult a good workshop. It's not so safe to drive with abnormal sound coming from engine.

[shorty_bari]

@UAHMAD any recommended workshop in Lahore? i would not want to go to my "ustad" now. Since he failed to figure out what the issue is. I live in DHA area Lahore

[UAHMAD]

I live in Rwp/Islamabad. Lahore based members can guide you better.

[UAHMAD]

Clogged fuel injectors can cause knock on idle. But the OP is experiencing it during acceleration.

Also, clogged injectors can result in loss of power, which is not the case here.

[shorty_bari]

sometimes i wish i could just dip the whole bloody car in WD40 for few mins. that should solve 80% of my problems with an old car

[UAHMAD]

Take it easy. Most of us are in the same boat.

Old or new, after all it's machinery. Can start to give troubles anytime. Even newer cars sometimes develop complicated defects.

In your case it may be a small problem causing this abnormal sound, not necessarily a major issue.

[shorty_bari]

hello hello. actually i cant get this noise out of my mind. because when after a few days when the issue randomly dissappears, the car drives much better during that trip . engine is more responsive as well, and i just wish i could experience that tiny leap of performance every day.

any experts want to also give in their 2 cents ?

my next guesses are:

1. knock sensor (but there is no check engine light)

2. oxygen sensor ?

3. manifold issue (someone told me there is JAALI in the manifold that might break and make this noise?)

4. What else? throw your guesses at me

[hash4u]

you should start with knock sensor

[haseeb.basharat]

How's the rpm on idle? Tried scanning it?

[shorty_bari]

do you know if the knock sensor can be bad without turning the CEL on?

[shorty_bari]

the idle is fine. but there is some excessive vibration when in gear and on a stop light.

[UAHMAD]

Actually there can be various reasons for the kind of noise/rattling that you are experiencing. There can be guess work only till a competent mechanic diagnoses it with proper tools.

Possibility of intake manifold loose or broken baffle, which you've mentioned may be looked into if the sound is somewhat like this:

Coincidentally, I have also been observing an abnormal sound coming from engine bay of my car for last few days. It's 1NZ FE. After showing it to three different mechanics I am now trying to diagnose the problem myself. Having ruled out timing chain and tensioner, engine bearings etc. I now feel that it is very clearly coming from location of the intake manifold and rattling is almost the same as in the YouTube video. So I have bought a replacement manifold. Let's see if it fixes the problem:

[haseeb.basharat]

Check washels under maf sensor.
Check all intake hoses and pipe. They shouldn't be loose at all. Check vacuum pipes clamps too.
Then you can go for air intake manifold.