1 NZ-FE Axio 1.5 knocking issue

hasanyusaf (hasanyusaf) 2017-06-24 17:24:32 +0500 #1

My Axio driven 120,000 kms. Knocking starts after the car is driven 5 Kms or more... After cold start there is no knocking till almost first 5 Kms... After that acceleration is normal... Knocking only occurs when the car gains some speed and rpm drops to near 1100... If accelerator is pressed...rpm goes up and knocking disappears...

I've changed air filter, oil and oil filter, cleaned throttle body... Replaced coolant. CVT oil also replaced with the correct procedure and Toyota original CVT oil TC.fuel filter and pump also replaced recently

Previously there was some thick oil in the engine and there was no knocking but I replaced it as soon as I bought the car. now I've put in shell helix HX-7... No CEL is on and scanner shows no pending codes....

Is it due to timing over advanced when rpm drops and knocking is caused???? Is the oil too thin for the age of the engine and oil pressure gets low?? Plz comment on this issue... Coz engine otherwise is perfect and there's water in the exhaust and no oil or carbon... Acceleration and consumption is also good. Only the knocking is bothering...

taimurahmed92 (taimurahmed92) 2017-06-24 17:30:52 +0500 #2

Try dumping your current fuel and use Shell V Power. I had the same issue with my lancer. I had plugs changed, fuel system cleaned and all. Issue was ultimately that fuel was bad. My car loves Shell V Power. I used to fill PSO and Total HOBC but that was also of poor quality and the car would knock. Knocking vanished the moment I filled my tank with Shell HOBC (and have used V Power since it came). Don't know if their fuel improved after the introduction of the new brands.

These newer cars have knock sensors and many other sensors designed to detect and eliminate knocking in real time. The only things that beats them is if the fuel RON Rating is lower than that for your car. Usually, it's RON 90 for most vehicles nowadays. The car's ECU can't adjust timing if the fuel quality is lower than the minimum.

hasanyusaf (hasanyusaf) 2017-06-24 17:53:34 +0500 #3

Thanx for the input brother... My tank is presently 100% shell HOBC... I suspected it's the fuel quality that's y ran the tank almost empty and filled in 100% hi octane... But knock still there...
It's bcoz of some other reason than fuel Ron number...

One mechanic said that it's due to vvti system over advancing the timings... Is this a possibility???

I previously owned a belta 1 KR which had the same issue... But that 1 improved a lot after hi octane usage... I shifted to 1.5 engine for the same reason and it also knocks...

taimurahmed92 (taimurahmed92) 2017-06-24 18:09:59 +0500 #4

The ECU should not be over advancing the timing by itself. Perhaps the more experienced members on the forum can shed some more light.

hasanyusaf (hasanyusaf) 2017-06-24 19:31:00 +0500 #5

U r right... That's why I don't let that mechanic operate any further... But maybe he was trying to convey something else... Experts plz comment...

hasanyusaf (hasanyusaf) 2017-06-24 22:07:09 +0500 #6

After start and even after reaching normal operating temp... There is zero knocking... After driving for a few kilometers only then the knocking starts at low RPMs... It's very annoying...

capsat (ومن شر حاسد إذا حسد) 2017-06-24 23:55:18 +0500 #7

scanner will give you code for emission which means either of the 2 O2 sensors (pre & post) at the exhaust manifold has gone bad. replace, test & post results please Thank you

SpeedDemon (SpeedDemon) 2017-06-25 01:06:50 +0500 #8

You can also check if the vvti solenoid is operating properly. Sometimes the sludge in the oil jams it since it runs on oil pressure. that may be causing incorrect valve timing...

capsat (ومن شر حاسد إذا حسد) 2017-06-25 11:12:15 +0500 #9

in Lahore at Obama car care centre 0321 4106898 Tipu block Garden Town lahore it can be resolved.

hasanyusaf (hasanyusaf) 2017-06-26 23:35:53 +0500 #10

Vvti solenoid was removed and cleaned thoroughly... There wasn't any sludge in it apprently... I disconnected the vvti solenoid and drove around... Pretty much the same situation....

I've poured in shell helix ultra 5w-30... Is it that the oil is too thin (low viscosity) to maintain a good enuff oil pressure? Which causes the engine to knock when it goes hot? After start and initial few Kms of driving.. everything is smooth... It's after 5-6 Kms the knocking starts at low rpm...

hasanyusaf (hasanyusaf) 2017-06-26 23:37:22 +0500 #11

Brother I'm in Karachi... No access to Lahore filhaal... Kindly suggest a knowledgeable ustaad in Karachi... Who actually can diagnose...

capsat (ومن شر حاسد إذا حسد) 2017-06-27 01:17:24 +0500 #12

get it scanned from Jamil Autos - 0300 9232821 week days 10.30 am to 7 pm,. it can be resolved

hasanyusaf (hasanyusaf) 2017-06-28 01:29:30 +0500 #13

Thank you so much. I'll post the results here as soon as I visit..

farrukhzeeshan (farrukhzeeshan) 2017-06-28 02:20:19 +0500 #14

Try to check intake air temperature, car is not knocking at start due to low intake temp, and once engine bay heats up the air intake system soaking heat resulting knocking. There must be some leakage in intake pipe and car is sucking very hot air from engine bay. No harm in inspecting it.

msalim (Sunny Automobiles) 2017-06-28 16:06:10 +0500 #15

Dear Brother, as a professional I have to thing about which component of the vehicle become warm, hot or over voltage that change the specification of the the car into knocking, there are alot factors involved in it, that will be examined during the tuning process, please make an appointment with out any charge, reason that I am offering you, that car will be ok, Many make of the Japanese vehicles has a problem when its become hot, they start knocking, many of them if the exhaust are not proper, its also knocking. If you would like to visit me please. Pls contact Sunny Automobiles, I-10/3, Saleem

msalim (Sunny Automobiles) 2017-06-28 16:14:06 +0500 #16

Yes Brother, In ECU, the manufacturer can't leave or gave any access to approach to ECU, no body can can change the specification of the engine and others system, like Ignition Timing, fuel adjustment, Etc.

hasanyusaf (hasanyusaf) 2017-06-29 00:16:36 +0500 #17

So nice of you for the generous offer. I'm presently in karachi. I would be in Rawalpindi with the car after about a month. Would definitely visit you then. Thanx again.

hasanyusaf (hasanyusaf) 2017-06-29 00:19:48 +0500 #18

I checked the air passage thoroughly... After passing thru the air filter... There's no leak... All joints are firm and sealed... I checked the air intake temp value via techstream after driving around for half an hour and air intake temp was 44 C.... which is normal so no hot air issue.. Thanx for the advice brother.

hasanyusaf (hasanyusaf) 2017-06-29 00:23:19 +0500 #19

This is exactly what's happening... After running a few kms...there is some component or sensor getting hot or high which causes the knocking...
I'm gonna visit jamil as adviced by @capsat tomorrow...I hope he's back from Eid holidays...

hasanyusaf (hasanyusaf) 2017-06-29 00:31:52 +0500 #20

It rained here in Karachi after ages... When I left home... OAT was 34°C but as it started raining... Temp came down to 26°C and there was no knocking at any rpm at all. There is definitely something overheating which causes the knocks...

I've poured shell helix ultra 5W-40 which is very thin to the feel even when engine is dead cold... If I pour petron 20W-50 then maybe it won't get very thin after getting hot and maintain optimum lubrication and cause no knocking.. what say experts? Car is driven around 130k Kms.

Oil pressure operates the vvti which retards or advances the timings... If oil is too thin maybe it effects the operation of vvti which causes the over advancement of timings causing loss of power and knocking... Just a wild guess... Again experts kindly comment.