How to clean the cylinders/combustion chamber w/o opening the engine?

[ahmadbila]

But have you checked your cars knock sensor that also might be faulty

wont that trigger the check engine light? i got the ecu scanned some time back, the only error was o2 sensor, that too, because of CNG kit. but still, thanks for pointing out, i ll get it checked again.

[ahmadbila]

Its done through software. You have driven ur engine 250k! So you will have to make certain adjustments, i think its ok. You can either do that or try to get hold of some really nice supply of hi octane. Its better than damaging ur engine.

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well, i ve been getting tuning done after every 40k kms, not even 1 of them was missed. so i think the car IS adjusted according to its life. but changing the timing of a car is not normal. its a very basic characteristic of an engine, u have to have a very gud reason to do it. offcourse, the timing can either be set to advanced by the cng advancer or it would be at stock position when the advancer is off. mine is off, so its at stock. as for high octane. thats impossible for me to get, unless a buy a whole tanker from lahore or sumwhere, theres no way i can get it in Sargodha.

[fahadwizz]

Some of the newer ecus automatically retard the timing in case of knocking. The 2009 city had this problem in their first lot because the engine expected a better quality fuel. The ecu in the later lot was reprogrammed as per paki fuel at the cost of some acceleration. A good enough reason would be to save ur pistons from those horrible detonation marks.

I have seen many 3g cities having knock issues and they are mostly solved by using 1/2 tank of hi octane mixed with super. If you dont have the option of filling octane every now n then retarding the timing is a nice solution. Its nothing permenan u can always advance it later and i dont think there is a major draw except for a slight compro on acceleration

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[jz]

it removes the excessive carbon,tryed it once,didnt really feel any noticeable difference.

@ahmedbila why dont you try engine flush that might help

[ahmadbila]

Some of the newer ecus automatically retard the timing in case of knocking. The 2009 city had this problem in their first lot because the engine expected a better quality fuel. The ecu in the later lot was reprogrammed as per paki fuel at the cost of some acceleration. A good enough reason would be to save ur pistons from those horrible detonation marks.

I have seen many 3g cities having knock issues and they are mostly solved by using 1/2 tank of hi octane mixed with super. If you dont have the option of filling octane every now n then retarding the timing is a nice solution. Its nothing permenan u can always advance it later and i dont think there is a major draw except for a slight compro on acceleration

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hmmmm... yes i know about the city 09 issue. so, can u suggest me how to do that? can it be done using the OBDII scanner devide? any workshop that u know of in isb/rwp or lahore?

[ahmadbila]

bumping...

[talhawaleed]

Your problem is not carbon buildup, one or more Ignition coil in this vehicle are bad. Get it diagnose and changed.

CNG vehicles don?t have an issue of carbon built-up, it?s a problem with Petrol Vehicles. Secondly don’t trust too much on OBD diagnostic tests, as it does not highlights a bad ignition coil.

[ahmadbila]

Your problem is not carbon buildup, one or more Ignition coil in this vehicle are bad. Get it diagnose and changed.

CNG vehicles don?t have an issue of carbon built-up, it?s a problem with Petrol Vehicles. Secondly don’t trust too much on OBD diagnostic tests, as it does not highlights a bad ignition coil.

ignition coil? wont that give massive jerks if the coils leak or fail to fire a particular cylinder? can u please explain how bad coils can cause knocking? i cannot connect the dots.
as for cng thing, yes, in pure terms, that wud be right. CNG burns cleaner then petrol but the problem is, our CNG is not clean. almost always, it has some oil in it which burns inside the c.c and leaves carbon behind. what do u think about that?

[shazo]

Ahmed bhai just replace ur coils i think there r 8 coils in city

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[NakedTruth]

ignition coil? wont that give massive jerks if the coils leak or fail to fire a particular cylinder? can u please explain how bad coils can cause knocking? i cannot connect the dots.
as for cng thing, yes, in pure terms, that wud be right. CNG burns cleaner then petrol but the problem is, our CNG is not clean. almost always, it has some oil in it which burns inside the c.c and leaves carbon behind. what do u think about that?

True.

There is a nut (screw) under the CNG kit. Open it and see how much oil comes out.

[talhawaleed]

Its definitely coils, no matter what you say, emissions from CNG are minimal as compared to Petrol. Oil normally comes into kit which causes jerking and immediately the issue can be diagnosed and symptoms can only be seen on CNG. what you are experiencing is on both CNG and Petrol so its definitely Coils. Few Vehicles such as Liana have Methane Filter which prevents oil from travelling into cylinders and injectors. If you are little used to occasional rash driving then this also helps a lot to get rid of carbons. Anyway, open the drain nut from CNG kit and get rid of oil from the kit. Natural Gas is a Natural Gas, you can’t say it’s clean or dirty based on that we are Pakistan.

[a_n_memon88]

AoA all...
Its been a veryyy long time that im trying to combat pre-ignition/detonation/knocking or whatever in my car's engine and its a combat i have lost miserably. The knocking is sooo much that even the passengers at back seat can CLEARLY hear it. What i hear is not just tik tik sound, its the sound of my engine being destroyed, which i wont like at all!
Until now, cars were driven on CNG and most of us know, due to high octane rating, knocking doesnt happen on CNG. Now, however, situation is different. Car is being driven on petrol all the time. And knocking is eating the engine day in day out.

The car has 255,000kms on it, its a 2006 Honda City idsi. I ve tried almost everything that I though could even remotely have connection with the issue but no, didnt help.

I ve used high octane petrol, it did decrease the knocking but due to geographical reasons, i cannot use high octane all the time + its expensive too. I ve got the car properly tuned up, valve clearance, plug replacement, injector cleaning by fuel additives AND by taking them out, fuel pump and filter replacement, reseting the ECU, switching to different grade engine oil, disconnecting the CNG advancer while on petrol and God knows what else, nothing helped at all.

Now, it hit me that i havent tried to fix one issue that can be a major reason of pre-ignition, which is carbon build ups in the combustion chamber. This buildup gets very hot and starts to glow and cause pre-ignition. This is what i'm going after now.

As far as i know, theres a liquid called "Seafoam". U can pour it down ur fuel tank or directly into throttle body. It would clean whatever comes into its way. I plan to use it through the throttle body, may be some of it from the fuel channel too. Theres only one problem, it isnt available in Pakistan or may be im unaware of its availability.

So the real question is, is there a way to clean the combustion chamber? is Seafoam or any similar product available in Pakistan for liqui moly or some other trusted brand? or can it be shipped somehow to Pakistan? will the seafoam hurt anything? im concerned about the sensors specifically and the catalytic converter.

help needed badly...

Regards

Time for another marathon. Tamam hazrat say guzarish hay kay hazmay ki goli kha kay yeh post parhein.

First of all Ahmed bhai you need to post the sound clip of that tick tick sound so that we can comment exactly what is it. For that tick tick sound there are 2 things.
1 Knocking
2 Engine

Lets take the first case i.e knocking. First of all very important thing is what is knocking. Knocking is the ignition of air fuel mixture at a time when the piston is moving upwards i.e still in the compression stroke. As the piston is moving upwards and is connected to crankshaft so it cannot move downwards immediately with the ignition hence it hits the piston hard and produces a sound that sounds like knocking. To my limited knowledge 80-90% of the time knocking is related to ignition timing.
Another question arises here is that why the car from factory does not knock and when they are old they knock. The reasonse for knocking are
1 Petrol which has very low RON.
2 Antiknock sensor not working or some other sensors not working optimally
3 Timing too advanced for the operation of vehicle under use.
First of all coming to petrol and RON. Higher the RON of petrol the slower it burns i.e the time it takes from a spark to a big flame. This means that the fuel that has low RON will burn quicker than the one with high RON. So the petrol we have in Pakistan is of low RON and will burn quickly and produce knocking. To eplain this we have to consider something about ignition timing, what is it. Ignition timing is the timing when the air fuel mixture is ignited. It is measure in degrees BTDC i.e before top dead centre. As the mixture is ignited it formes into a big flame certain degrees ATDC i.e after to dead centre. Now comes the point that higher the RON of fuel the greater we have advance its timing so that the ignition turns into a large flame certain degrees ATDC. Every engine has its specific ATDC for optimum performance. Now take a rough example. Suppose an engine is made for 91 RON fuel and its timing is 10 BTDC such that flame is produced 5 ATDC now the burning time of mixture is 15 degrees i.e 10-(-5). Now suppose we feed the car with 93 RON whos burning time is 17 degrees. Now if we dont change the timing what will happen that the flame will be produced at 7 ATDC far beyond engines most effective performance point. To take care of this what we can do is advance the timing so that flame occurs at the most optimum point. Advancing the timing by 2 degrees is the right action but if we advance the timing but 7 degrees now what will happen. With even 93 RON fuel the flame will occur at 0 ATDC too away from most effective point and with 91 RON it will occur at 2 BTDC and will produce knocking. That is the reason our cars that are run on CNG knock on petrol and keep in mind that RON of CNG is well beyond 100 RON so optimum performance is not possible for both fuel.
In efi cars we use advancer for the advance of timing on CNG and it advances according to its calibration. Another thing in most efi cars and the one under condition particularly is that the timing changes with rpms and demands of engine. Why an engine requires to changed its timing with the changing rpms. The answer is that as the rpms increase the timing between each movement of a piston in the cylinder decrease so if the timing is not advanced it wont be possible for the flame to be produced at optimum ATDC, because we cannot increase the burning rate of fuel with our changing demands. So the ecu works like this it tends to retard the timing at lower rpms and advances it at higher rpms.
As the signals to the ecu are fed by sensors so the sensors have to be working correctly for proper operation by ecu. The sensors that come to my mind are knock sensor, TPS, MAF sensor, O2 sensor they all have to be spot on even one of them is not performing the required performance cannot be achieved.

If we take this tick tick as anything other than the knocking than it can only be said after hearing the sound. And yes talha bhai said its coils. Coils can also be the culprit because because they might be sending the current to the spark plugs too late and that is why knocking

Now coming to the conlusion and remedial actions to take.
I dont think its the carbon buit up thats causing the problem because each time the piston moves up the oil cleans the cylinder walls so there is less of chance of carbon built up there. The knocking is usually not permanent I mean to say its not on all engine speeds. i,e a engine can not knock at all engine speeds ideally most engines dont knock at higher rpms because there as less time to burn is require so the fuel that was causing knocking in low rpms would not knock at higher ones. Now the remedial actions are I would like to advise is that find yourself an idsi that is on low miles and runs perfectly. Connect to OBD II scanner to that car and note down the readings like, timing, and there are other things as well that I dont remember. Take all readings at 500 rpm interval i.e at 1000,1500,2000 so on till 5500 rpm. Because the owner of that second car is not going to allow you redline his car:P infront of his eyes. Now take a drive and again note down the readings at different speeds i. 30,50,60,70 etc. But here you have to keep the rpms and gear noted because you are going to take similar test on your car as well so you can be in a better position to decide. After all the readings have been noted take the same readings on your car. Now compare both I hope that you will find the culprit. As your car is a high miles car and its run on fuel >100 RON so it seems a pssibility that some or any one of your sensors has malfunctioned or about to die so it is not sending proper signals to ecu to retard the timing and hence producing knocking. Check engine light only lights up when a sensor if fully dead so if its working on its 10% the CEL wont light up.
Still I will be waiting for the sound clip to know what actually the sound is. Do update us about the results
Regards

[fahadwizz]

Time for another marathon. Tamam hazrat say guzarish hay kay hazmay ki goli kha kay yeh post parhein.

First of all Ahmed bhai you need to post the sound clip of that tick tick sound so that we can comment exactly what is it. For that tick tick sound there are 2 things.
1 Knocking
2 Engine

Lets take the first case i.e knocking. First of all very important thing is what is knocking. Knocking is the ignition of air fuel mixture at a time when the piston is moving upwards i.e still in the compression stroke. As the piston is moving upwards and is connected to crankshaft so it cannot move downwards immediately with the ignition hence it hits the piston hard and produces a sound that sounds like knocking. To my limited knowledge 80-90% of the time knocking is related to ignition timing.
Another question arises here is that why the car from factory does not knock and when they are old they knock. The reasonse for knocking are
1 Petrol which has very low RON.
2 Antiknock sensor not working or some other sensors not working optimally
3 Timing too advanced for the operation of vehicle under use.
First of all coming to petrol and RON. Higher the RON of petrol the slower it burns i.e the time it takes from a spark to a big flame. This means that the fuel that has low RON will burn quicker than the one with high RON. So the petrol we have in Pakistan is of low RON and will burn quickly and produce knocking. To eplain this we have to consider something about ignition timing, what is it. Ignition timing is the timing when the air fuel mixture is ignited. It is measure in degrees BTDC i.e before top dead centre. As the mixture is ignited it formes into a big flame certain degrees ATDC i.e after to dead centre. Now comes the point that higher the RON of fuel the greater we have advance its timing so that the ignition turns into a large flame certain degrees ATDC. Every engine has its specific ATDC for optimum performance. Now take a rough example. Suppose an engine is made for 91 RON fuel and its timing is 10 BTDC such that flame is produced 5 ATDC now the burning time of mixture is 15 degrees i.e 10-(-5). Now suppose we feed the car with 93 RON whos burning time is 17 degrees. Now if we dont change the timing what will happen that the flame will be produced at 7 ATDC far beyond engines most effective performance point. To take care of this what we can do is advance the timing so that flame occurs at the most optimum point. Advancing the timing by 2 degrees is the right action but if we advance the timing but 7 degrees now what will happen. With even 93 RON fuel the flame will occur at 0 ATDC too away from most effective point and with 91 RON it will occur at 2 BTDC and will produce knocking. That is the reason our cars that are run on CNG knock on petrol and keep in mind that RON of CNG is well beyond 100 RON so optimum performance is not possible for both fuel.
In efi cars we use advancer for the advance of timing on CNG and it advances according to its calibration. Another thing in most efi cars and the one under condition particularly is that the timing changes with rpms and demands of engine. Why an engine requires to changed its timing with the changing rpms. The answer is that as the rpms increase the timing between each movement of a piston in the cylinder decrease so if the timing is not advanced it wont be possible for the flame to be produced at optimum ATDC, because we cannot increase the burning rate of fuel with our changing demands. So the ecu works like this it tends to retard the timing at lower rpms and advances it at higher rpms.
As the signals to the ecu are fed by sensors so the sensors have to be working correctly for proper operation by ecu. The sensors that come to my mind are knock sensor, TPS, MAF sensor, O2 sensor they all have to be spot on even one of them is not performing the required performance cannot be achieved.

If we take this tick tick as anything other than the knocking than it can only be said after hearing the sound. And yes talha bhai said its coils. Coils can also be the culprit because because they might be sending the current to the spark plugs too late and that is why knocking

Now coming to the conlusion and remedial actions to take.
I dont think its the carbon buit up thats causing the problem because each time the piston moves up the oil cleans the cylinder walls so there is less of chance of carbon built up there. The knocking is usually not permanent I mean to say its not on all engine speeds. i,e a engine can not knock at all engine speeds ideally most engines dont knock at higher rpms because there as less time to burn is require so the fuel that was causing knocking in low rpms would not knock at higher ones. Now the remedial actions are I would like to advise is that find yourself an idsi that is on low miles and runs perfectly. Connect to OBD II scanner to that car and note down the readings like, timing, and there are other things as well that I dont remember. Take all readings at 500 rpm interval i.e at 1000,1500,2000 so on till 5500 rpm. Because the owner of that second car is not going to allow you redline his car:P infront of his eyes. Now take a drive and again note down the readings at different speeds i. 30,50,60,70 etc. But here you have to keep the rpms and gear noted because you are going to take similar test on your car as well so you can be in a better position to decide. After all the readings have been noted take the same readings on your car. Now compare both I hope that you will find the culprit. As your car is a high miles car and its run on fuel >100 RON so it seems a pssibility that some or any one of your sensors has malfunctioned or about to die so it is not sending proper signals to ecu to retard the timing and hence producing knocking. Check engine light only lights up when a sensor if fully dead so if its working on its 10% the CEL wont light up.
Still I will be waiting for the sound clip to know what actually the sound is. Do update us about the results
Regards

Very well explained.

[a_n_memon88]

Very well explained.

Most of the problems are solved by understanding what things actually are that is why I tried to explain what knocking is and not every other clicking sound from engine is knocking

[ahmadbila]

True.

There is a nut (screw) under the CNG kit. Open it and see how much oil comes out.

It shouldnt be much. I got it cleaned last year.

[ahmadbila]

Ahmed bhai just replace ur coils i think there r 8 coils in city

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hmm yeah there are 8 coils... i ll look into it. I think i should read a_n_memon's jahazi size post first

[a_n_memon88]

It shouldnt be much. I got it cleaned last year.

CNG kit me oil ka petrol ki running say kya taaluq hai?

[Xulfiqar]

to clean the combustion chambers, a product called kreen is the best, GM, Ford and Chrysler also have their own proprietary cleaners which are very heavy duty and require a professional mechanic to perform the job.

Such products are used by feeding the engine in a flooding technique till the engine balks and stalls out. Then the ignition system is disabled and the same liquid form of the same product is then injected into the cylinders after removal of plugs and the engine rotated by hand then left alone overnight in normal ambient temperature of no less than 10C and no more than 30C.

the next day the engine is cranked manually and then with the starter - after the black goo has stopped coming from the cylinders the plugs are installed back, the engine oil is changed along with filter and the engine is started in an open atmosphere environment and held at 2000 rpm - it will smoke like a Pakistan Railway loco for a few minutes. Engine is now clean.

One mistake on this procedure can cause the engine to completely sieze of even sometimes hydrolock.

Liqui moly also have such a product - its called intake valve cleaner you can feed it to the engine mixed with some petrol but if your engine has a cat converter make sure you only feed it less than 200cc otherwise you might destroy/melt the cat.

[a_n_memon88]

to clean the combustion chambers, a product called kreen is the best, GM, Ford and Chrysler also have their own proprietary cleaners which are very heavy duty and require a professional mechanic to perform the job.

Such products are used by feeding the engine in a flooding technique till the engine balks and stalls out. Then the ignition system is disabled and the same liquid form of the same product is then injected into the cylinders after removal of plugs and the engine rotated by hand then left alone overnight in normal ambient temperature of no less than 10C and no more than 30C.

the next day the engine is cranked manually and then with the starter - after the black goo has stopped coming from the cylinders the plugs are installed back, the engine oil is changed along with filter and the engine is started in an open atmosphere environment and held at 2000 rpm - it will smoke like a Pakistan Railway loco for a few minutes. Engine is now clean.

One mistake on this procedure can cause the engine to completely sieze of even sometimes hydrolock.

Liqui moly also have such a product - its called intake valve cleaner you can feed it to the engine mixed with some petrol but if your engine has a cat converter make sure you only feed it less than 200cc otherwise you might destroy/melt the cat.

That looks like a hell difficult job and it looks like one has to take great care to even attempt it. But I have one question is there anyway we can avoid such buildup in combustion chamber

[ahmadbila]

CNG kit me oil ka petrol ki running say kya taaluq hai?

first off, i ve read ur wonderful post. i ll get back to it in a while. at the time im busy with my professional ethics module on acca website
secondly, oil does not stay in the cng kit, it travels to the combustion chamber with the gas and burns there. because it burns, it leaves carbon there. on the top of the piston, the valve's lower side and other areas... this carbon can get very hot n it starts to glow n hence can cause knocking, actually it causes pre-igniton.