Knock sensor detecting knoks

What exactly is a knock? Is it bad for your engine and if it is, how do I fix it? Thanks.

 

Check spark plugs? Try mid-grade fuel? Pinging is bad and can damage the cylinder over time.

 

Don't really know how to check spark plugs and I've been running 91 octane since I got it. Isn't it bad to go to a lower octane if I've always been running 91?

 

What's the code?

 

My CEL isn't on, so I have no code. I bought and OBD2 scanner and I got a knock detector app. I ran it and it said I had several knocks at different RPM points. Is this bad, normal, or should I do something about it. I don't really hear anything from the engine. I am running an intake, headers, exhaust, and TBS.

 

How many miles since you changed the plugs? or how many miles are on the truck now?

 

I have less than 50,000 miles on the truck and I think I replaced them at 30,000 if that is what the dealer recommended but I can't remember.

 

An engine knocking can be caused by several reasons. Bad spark timing, bad plugs and coils, bad fuel, lean condition in the cylinder. Could also be a lot a carbon buildup that is causing a hot spot. I ran seafoam through my truck and let it sit for a few hours. You would not believe the chunks of carbon that came out of my tailpipe. I also don't know if you need to run 91 octane? I know they needs it in 2005 but I thought they changed that. You can swap from 91 to 87 no problem as long as your engine doesn't require 91

 

My engine doesn't require 91 but I thought it was a good idea to run it to keep the longevity of the engine. I heard you get better gas mileage and run a cleaner engine with less gunk. Am I wrong in thinking this? So, I should run sea foam to try and fix the problem? I believe my engine could be running lean because of all the mods I did but I'm not getting a CEL. I'm planning on buying the URD maf calibrator to even the air fuel ratio. What are your suggestions?

 

what is the problem....

 

All the 91 octane does is resist detonation for a higher compression ratio. It won't do anything for a stock engine as far as more hp, better economy, etc. I doubt you need 91. Your probably just wasting money. And your ECU should be able to recalibrate the a/f mixture for your mods. With less then 50k miles you shouldn't have any carbon buildup. On my 60k nissan the tops of the pistons were still silver. My taco has almost 160k. So I have carbon buildup As far as your problem, if there is no CEL then I don't see how your knocking. The engine would pick it up and throw a code, flipping the CEL. I'm thinking the app your running is saying something that is not actually happening. If your really worried, go to the dealer and tell them your problem. Ask if they would do a test with their scanner to confirm. Most should free of charge.

 

Stop running 91... It may not fix the knock but it's literally a waste of money. Unless your running higher than stock compression there's no reason for it. It does nothing to help the engine, that's a common misconception.

 

^again what he said. I hear it all the time. Some people do after many miles because of the carbon buildup. It creates hotspots on the pistons that detonate the fuel early. You should not have this problem

 

My POS '12 has knocked from day one as well, regardless of what gas I used. So I am back down to 87 because I basically don't give a damn about the octane rating. Lol.

 

I've read the octane thread and a lot of credible memebers, like chris4x4, say running 91 octane improves performance and mileage. I just thought since ai have some performance mods, I should run the higher octane to even things out. I'm skeptical about going down to 87 unless it will fix my knock. My main purpose of using 91 octane was to preserve the engine life because I plan on keeping my truck for a long time. I'm very happy with my truck but always looking for more performance upgrades. The knock and what you all have posted kind of scares me now. I don't want to do damage to my engine but I do want performance gains.

 

It just means your one step closer to a diesel haha

 

It improves performance and mileage if you have done something to change your compression ratio. Otherwise it's not doing anything. If it was that easy to get more power and mpg I would be running race fuel haha

 

I have not done anything to my compression ratio yet... What will fix my, alleged knock, from my knock sensor reading off an OBD2?

 

Read the Owner Manual. Some knocking is completely normal according to Toyota. Depends under what RPM/driving conditions it's occurring. It's usually under accelerating onto the freeway and when the truck is "under load".

 

That is exactly when I got the knocking. So, leave it be or try the sea foam? And, can I stay 91 octane, or is that bad?