Knock Knock Knocking Engine. Help

[sunman]

I have a knocking problem in my 97 ES. I use 89 Octane Fuel. Always have. I replaced the plugs to NGK Iridiums. I also recently use BK44 Fuel cleaner. I can't exaclty pin point when the knocking started. Anyway, I can hear it if I open the window and accelerate on the highway. MAF is clean, air filter is new, oil changed recently, all fluids new. What can I do? Shall I try 93 octane fuel? I don't want to have to use 93 though. Is there anything else I can do?

[sunman]

Okay, I am not sure if it is pinging or knocking. What do they both sound like? I think it's more knocking when accelerating only. Not idle. Shall I change the plugs to platinums which came with the car?

[steviej]

run a few tankfuls of 93 or 89 from a different brand/station and see if it goes away.

It could be the gas, it could be the plugs or it could even be a lazy knock sensor.

start with the easy cheap things and process of elimination.

steviej

[sunman]

I use shell gas. I will try a difrferent gas first. Then change plugs. I will check my maintaince manual for the knock sensor. Does anyone know how much it costs? Is it normal to go bad? I have 118,000 miles.

[bartkat]

I use shell gas.  I will try a difrferent gas first.  Then change plugs.  I will check my maintaince manual for the knock sensor.  Does anyone know how much it costs?  Is it normal to go bad?  I have 118,000 miles.

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Got the correct heat range plugs?

Pinging (pre ignition knock) will mostly happen when the engine is under load in a higher gear like going up a slight hill. It would sound like a clatter that you don't normall hear on a level road at normal throttle. The knock sensor causes the ECU to !Removed! timing to prevent knock, but it can only do so much.

Could be your ECU got used to a certain quality gas, and if quality declined, then it's not going to adjust right away. You might reset the ECU and let it go to the default settings, and see how tha works first.

Personally, I'd run the tank down pretty low and then fill with 91 or 93 octane gas, rather than just change brands.

[sunman]

I have a feeling it was the plugs then. I have been running 87 now as of yesterday. I assume if I unplug the battery for 20 minutes, it will reset the ECU? I may just go ahead and change back to platinum plugs then. THat may solve my problems.

[sunman]

and yes, it does sould like clatter when going up hill or with a load. So it must be pinging then,.

[bartkat]

I have a feeling it was the plugs then.  I have been running 87 now as of yesterday. I assume if I unplug the battery for 20 minutes, it will reset the ECU? I may just go ahead and change back to platinum plugs then.  THat may solve my problems.

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Yes, that should work for resetting the ECU. Disconnect the Negative (black) cable only. .

[svarog]

If you changed oil recently it also could be bad oil. At least thats what i read somewhere, wrong oil might make your engine knock

[sunman]

I use AMSOIL 5w-30 Synthetic so I am pretty sure it's good stuff.

[sunman]

how often does someone replace a knock sensor? I have never replaced one in my life and I have been through some pretty high mileage toyota's. Camry with 485k, 4Runner with 240,000k...

[mxl4729]

I use shell gas.  I will try a difrferent gas first.  Then change plugs.  I will check my maintaince manual for the knock sensor.  Does anyone know how much it costs?  Is it normal to go bad?  I have 118,000 miles.

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with 118,00 you should do a motorvac. it is only about a 100 bucks and i think it should be done evey 80k.

change back to the stock plugs, what ever it came from the factory with.

[SKperformance]

the iridiums are fine.

Why are you using 89 octane?

you spend so much modifying the car and use cheap gas?

Your engine is prone to engine carbon buildup so by useing lower octane your are compounding the problem.

[steviej]

knock sensors are replaced when they go bad. That will send a code. I don't know if they get lazy like and O2 sensor can. It stands to reason that they could. I think they are just had to get at that's all.

Keep it simple and cheap, work your way up.

Try the gas variation, then the plugs (like SK said), then the motorvac, then the knock sensors until you get to the source.

you can easily reset the ECU just by pulling the ECU fuse. No need to disconnect the battery.

steviej

[sunman]

Ok i got 87 gas, reset ECU. Knocking went away a little but still there on hills. What is motorvac? I assume some engine flush?

[Lexusfreak]

I believe motorvac is a professional fuel system flush that blows out any gunk in your entire fuel system.....they hook the car up to a machine to do this procedure (as opposed to pouring a bottle of stuff in the gas tank). When you changed the plugs, did you change the fuel filter & PCV valve as well? One might not have much (if anything) to do with the other, but if your injectors & fuel system are clogged, it sure couldn't hurt to change those other parts as well for preventitive maintenance as they most likely would be dirty as well. Try a few tankfulls of 93 or 94 octane gasoline as suggested also (I use Sunoco 94). Good Luck! B)

[mxl4729]

Ok i got 87 gas, reset ECU.  Knocking went away a little but still there on hills.  What is motorvac?  I assume some engine flush?

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a motorvac is a machine that connects to the engine thought the fuel lines. Normally at the fuel filter both the high-pressure and low pressure return fuel lines are removed and connected to the engine. the machine is filled with gas and industrial fuel cleaner. The machine is first run for 15 mins with the engine off and this cleans the fuel rail and all that stuff. During this time you take off the intake and spray cleaner inside the throttle body to clean all that carbon out.

Then the engine is run for 15 mis off of the machine and this cleans out the injectors and the backs of the valves and all that stuff.

This is really the best way to clean out all the carbon build up that really starts to accumulate at about 80k

Y do u have to get rid of all this carbon you might ask

Well the build up of carbon reduces you cylinder size. By reducing you cylinder size you are increasing you compression ratio. When you increase you compression ratio you need to run high octane gas or you will get pinging

Or sometimes the carbon gets red hot and starts to flake off under load. These red hot carbon flakes ignite the gas before it should be and can cause knocking.

So that is why you should get a motorvac

[bartkat]

Doesn't the glowing carbon also cause "run on" where the engine tries to "diesel" and hit a few times after the ignition is turned off. This was a common problem when unleaded gas first became mandatory.

[mxl4729]

Another way to get rid of carbon that one of the older guys in the shop taught me is to give your car some water to drink. I have done this to a couple of cars and it works good. make sure your car is nice and hot (you have warmed it up to normal operating temp) find a vacuum port on your throttle body and connect a tube to it. then crimp it in your hand. then stick the other end of the tube into a glass of water using your other had open up the throttle body to rev up the engine a couple of thousand rmp. when it is up there hold it and un crimp the tube a little. the car will suck in the water and stumble a little. regulate the crimp in the tube to keep the rpms at almost 2000.

You must be careful not to let the car stall when doing this. This is a nice cheep way to clean the carbon out of your system.

[jlmoreno911]

MXL>>WHAT!?? Please elaborate on this procedure...and how does it work/help??

[mxl4729]

MXL>>WHAT!??  Please elaborate on this procedure...and how does it work/help??

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a quick search on google proves i am not crazy and other people have done this take a look

http://www.hotrod.com/tipstricks/41918/index5.html

This is another tech-tip classic that some younger readers may not know. A carbon-fouled engine can be cleaned out quickly and easily by spraying water from a spray bottle down the carburetor while the engine is running. Run the engine at fast idle and squirt water down the primaries of the carburetor. A small amount of steam vapor out the exhaust is normal. The water turns to steam during the combustion process and helps remove carbon from the combustion chamber and piston tops. It may also help to clean the engine up a few days before your next smog test.

http://www.hotrodder.com/kwkride/tech.html

The best way to clean carbon build-up out of your engine is NOT to take the car out and run it as hard as you can. This only results in meetings with local law enforcement personnel, and doesn't do much for cleaning out carbon.

If you really want to clean the carbon out of your engine follow these simple steps. Fill an empty soda bottle with water. Remove your air cleaner. Start your engine. While using one hand to control the throttle, trickle the water into the carb or throttle body with the other while holding your thumb over the bottle opening. Keep the engine rpm's up so that the engine doesn't die. Make sure that you don't pour the water in too fast! Water doesn't compress and if you pour too much water in, severe engine damage can result! White smoke from the exhaust is normal. If you have a port fuel injected car, you obviously won't be able to use this method, but I have had success with connecting a vacuum hose to a port at the base of the throttle body and sticking the other end of the hose into the bottle of water. The vacuum of the engine will suck the water in, creating the same effect. This will clean out even the most stubborn carbon, by 'steam cleaning' your cylinders.

and many more take a look around cheepest way to clean carbon out

also from the above sight is this

Pinging, knocking and detonation are all terms for a condition known as "pre-ignition". That means some of the gas and air mixture is igniting in the cylinder before it's supposed to. And when that extra flame front crashes into the normal flame front (created by the spark plug), you hear a noise, and that noise is pinging.

There are four major causes of pinging. The first three are related to excessive heat.

The first is severe engine overheating. If the engine is running too hot for any reason, the temperature in the cylinders can simply be too high. In that case, some of the mixture can ignite before the spark plug fires just from the intense heat.

The second major cause of pinging is carbon buildup inside the cylinders and on the pistons. When too much carbon collects, it can reduce the size of the cylinders (increasing the compression and temperature of the cylinder contents) and retain excessive heat itself.

The third cause of pinging is a malfunctioning exhaust gas recirculation (EGR) system. The EGR is supposed to send non-combustible exhaust gas into the cylinders to lower the temperature of the mixture.

How does 800-degree exhaust gas LOWER the temperature in the cylinders? Because it doesn't burn, and it crowds out some of the oxygen that would have burned and made an even hotter flame. And if that EGR is not working properly, the cylinder temperature can be too hot and the engine can ping.

And finally, incorrect ignition timing can cause pinging. The ignition timing determines when the spark plugs fire. And if they're set to fire too early, the stuff will begin to burn too early.

The use of higher-octane gas often makes the pinging stop because it has a higher ignition point. By requiring a higher temperature to make the gasoline burn, you reduce the likelihood of it "pre-igniting" somewhere else in the cylinder.

But premium gas doesn't address the underlying problem. So start by checking the EGR system, the cooling system and the ignition timing. And if none of those things fix it, then you can consider using a higher-octane fuel.

second most reason is carbon so give it a try it is free

[SKperformance]

only older cars would "deisel "on as it would be carbourated which uses vacume to induce fuel while a fuel injected car shuts off the gas so a hot spot cannot ignite it.

[jlmoreno911]

Thanks for the details!

[steviej]

did you try 93 gas? run a couple of tankfuls.

steviej

[SKperformance]

btw stop using shell gas it is crap , use it for years for airmiles ,what an idot i was................

Within a few tanks of other gas from sunoco or anywhere else, my performance increased as did my milage and all 3 of my cars ran richer compared to leaning out alot.