3VZE Engine Knocking

[captwalker87]

Between the 2000-3200 RPM Range my engine pings and knocks. As the enigne revs higher, the knocking occurs at a constant rate. With my tranny in neutral, it still knocks. I tried locating the knocking while i was under the hood. Given the fan noise, i was able to pinpoint the noise below the top of the engine about 2 inches to the left of the "V6" symbol on top of the engine. I beleive the knocking might be tied to something with the oil. Ever since this starting happening, my oil pressure has been sporadic. While its idling (no knocking) the oil pressure guage reads right in the middle of the idle range. Normal driving, however, the oil pressure is anywhere inbetween normal to just at the idle line.

Any ideas?

 

[just66horns]

Knocking

What kind of oil are you using? How often have you changed it? What kind of fuel are you using?

Do you know what valve tap sounds like? How about rod knock. More detail please

 

[Gryphon]

how many miles do you have on the mill?

I would do an oil change if you have not done one recently, new filter and drop the pan when you do it. Check your pump and the suction, make sure the screen is clear and the pump looks good.

The knock may be the result of an oiling problem. Sounds like lifter noise. Mine does it too, but as long as I keep the oil clean and full, it is ok and makes no noise. I have 220k on it now.

Pinging is different. Detonation in the cylinders can cause lots of bad things. Check your fuel octane: is it correct for your engine? Some states (like Utah) sell "regular" at 85 octane rather than 87. How long since your last tune-up with new plugs? Maybe something as simple as a few tanks of gas with fuel system cleaner in it may help. I do this with every new (used...new to me tho!) car we have gotten...seems to help anyway. (detonation is often caused by junk in the combustion chamber.)

Another possability may be timing. Worn belts can cause timing issues and pinging, a bad or worn tensioner can knock...so can water pumps. Without a stethescope, it can be really tough to pin down the exact location of a noise.

 

[captwalker87]

I thought it was an oil problem also, so I did do a complete oil change. That did fix my Oil Pressure.. however the engine still knocks. Then i thought what you did. I did a basic tune-up.. new cap/rotar along with new plugs and i cleaned the wires throughly. Still knocks. Then i thought fuel delivery.. so i dumped 4 bottles of fuel injector cleaner into a 1/4 tank of 91 octane, i burned through that and it still knocks. However, I narrowed down the time it knock's. It only knocks when "barely accelerating." I drive a manual, so it only knocks when im diving it enough gas to coast.. not enough to move faster, but enough so im not engine braking. It is pretty loud, and Im not fimiliar with the noise, and its located 1" up and 2" right from the "V6" symbol on my engine. My buddy said it might be valves that have heated and warped ever so slightly, so they dont close all the way and rattle. any ideas?

 

[jeb]

I'm guessing here, but I doubt it's sticking valves, sounds more like heat related knock. Have you check for any sludge buildup? Reason I ask is I had the same problem. Everything checked out tune wise, so It had to be heat related knock. I found out I had a lot of sludge (please no change your oil at scheduled time comments, I have). What I did is run the amsoil internal engine cleaner, following instructions on bottle. This cleaned 70% of it up. Switched to synthectic, changed filter at 500 miles, ran 1500 miles and changed again. After this, engine ran cooler and knock virtually non-existant. Checked recently and sludge and varnish almost gone, but I'm only 2k into this. I also adjusted TPS which allowed a little more fuel, overcoming a lean condition, which can cause knock. Continuing to run synthectic will clean the rest up. The more I drive it, the better it gets. I still have some other problems, small ones, to work out, but so far everything is great. Almost forgot, changed PCV valve also, not completely clogged, but a little crude can hurt more than you think. Make sure your timing is right for your engine, probably 10 degrees for V6.

 

[regularguy412]

You may also want to clean inside the combustion chamber to remove some of the carbon deposits that build up, over time. These deposits become 'hot spots' during the combustion process and can be a cause of pre-ignition ( spark knock ). It mimics buring bad gas even if the gasoline, itself, is not too low in octane.

I have used Seafoam with good results. Be sure to get the appropriate Seafoam product ( available at most auto parts stores, Advance Auto, Auto Zone, etc) and follow the directions on the can. Be sure to use a vacuum source that allows the Seafoam to get into ALL the cylinders, then let it sit in there for 10 minutes. When you restart the engine, there will be a LOT of white smoke, at first. Then it will turn more blue in color. That's when the carbon deposits are being burned off, along with some oil.

Hope this helps.

Mike in AR

 

[92TXT4R]

My truck does the same thing. It will knock at certain RPMs and certain throttle positions. Decelerating at hwy speeds by letting off the throttle, etc. It does not do it at hwy speeds while throttle is applied, etc. etc. etc. I have changed plugs, done the seafoam treatment (although the seafoam DID eliminate the hesitation and sputtering I had been experiencing almost instantly), new air filter, etc. I've run everything from "regular" to "super" in it....the higher octane fuel seems to help somewhat...but not enough. I'm beginning to wonder if I've got some sort of timing issue....i.e. related to a bad knock sensor, etc. It is my understanding that the knock sensor basically advances and re****s timing based on fuel, driving conditions, etc, and that if it is not functioning properly, it can cause the vehicle's timing to be off.

Any more ideas fellas?!

Thanks in advance.