Engine knock
- Thread starter dryfly
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dryfly said:
This futher supports my earlier comments. You shouldn't run higher octane than the engine requires per spec. Higher octane means slower combustion/detonation. In an engine with advanced timing, higher compression, and/or under boost (as in S/C or Turbo) this may be necessary, but in a stock engine, this just leads to greater carbon formation in the engine, which can act like a glow plug. Go back to regular as well as change out the plugs/wires/etc., set the timing correctly, do a decarbonization, and save some $$$$ on gas.
dryfly, experience has shown that 80 series o2 sensors can be performing badly enough for you to fail emissions testing without throwing a code. I have no idea whether other systems might throw a code or not from a lean condition.
scamper, that reminds me of this thread where raventai has got apparent major carbon buildup based on his compression test results, and, by apparent coincidence, runs on 93 octane... https://forum.ih8mud.com/showthread.php?t=47917
here is an interesting take on pinging, that suggests pinging because of carbon buildup is not harmful
http://www.msgroup.org/Contrary/NEG037.html
scamper, that reminds me of this thread where raventai has got apparent major carbon buildup based on his compression test results, and, by apparent coincidence, runs on 93 octane... https://forum.ih8mud.com/showthread.php?t=47917
here is an interesting take on pinging, that suggests pinging because of carbon buildup is not harmful
http://www.msgroup.org/Contrary/NEG037.html
I don't think he's saying pinging as a result of carbon is not harmful, but is saying that it is different than pinging from other conditions. He even says as much in his comments if I understand it correctly.
But in any case, if you don't know the cause of the ping, it really doesn't matter if it's a "good" ping or a "bad" ping.
But in any case, if you don't know the cause of the ping, it really doesn't matter if it's a "good" ping or a "bad" ping.
I think it's either bad ping or meaningless pin but never good ping 
He says "In no case does the pinging from carbon cause engine damage" which seems pretty definitive. Here's the full quote:
"One source is excessive carbon buildup. That means nothing is wrong and the engine simply needs a good cleaning, ON THE INSIDE. The reason for the excessive carbon could be due to an oil consumption problem, either leaky valve seals or worn piston rings. Either way, the head needs to be removed to solve the root cause, the can be decarboned at the same time. An engine is normally good at burning away carbon on it's own. The problem could also be due to mal-adjusted carbs or a dirty air filter causing the engine to run way to rich. Again, that is a problem that needs correcting and a 1/2 bottle of Techron engine deposit cleaner will quiet it right up. In no case does the pinging from carbon cause engine damage."
You need to cure the problem as well as remove the carbon but if it is the wrong octane fuel that should be easy enough.
He says "In no case does the pinging from carbon cause engine damage" which seems pretty definitive. Here's the full quote:"One source is excessive carbon buildup. That means nothing is wrong and the engine simply needs a good cleaning, ON THE INSIDE. The reason for the excessive carbon could be due to an oil consumption problem, either leaky valve seals or worn piston rings. Either way, the head needs to be removed to solve the root cause, the can be decarboned at the same time. An engine is normally good at burning away carbon on it's own. The problem could also be due to mal-adjusted carbs or a dirty air filter causing the engine to run way to rich. Again, that is a problem that needs correcting and a 1/2 bottle of Techron engine deposit cleaner will quiet it right up. In no case does the pinging from carbon cause engine damage."
You need to cure the problem as well as remove the carbon but if it is the wrong octane fuel that should be easy enough.
I think we agree then.
[Caveman Lawyer voice]
Clean = Goooodddddd
Carbon = Baaadddd
[/Caveman Lawyer voice]
[Caveman Lawyer voice]
Clean = Goooodddddd
Carbon = Baaadddd
[/Caveman Lawyer voice]
semlin said:
I think that is my next step. So back to one of the questions above... what is a good, non-engine tear-down method of decarbing? Seofoam??
Thanks for the good feedback. I think you may be on to something with the 95-97's. As another datapoint, Andrewreef is another complaining of consistant pinging with his 97.
Rookie2
Edit: After reading the above link, that is exactly when my pinging occurs... low rpm, under heavy load. Like when right after the gears shift pulling up an incline.
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rookie 2, apparently some believe adding water into the intake is the best way to decarbonize. Before you laugh, remember that C-Dan does it all the time. What is needed is an accurate way to dispense it.
https://forum.ih8mud.com/showthread.php?t=45371&highlight=water+carbon
and before you start worrying about hydrolocking, MikeB on this thread says that seafoam can also hydrolock!
https://forum.ih8mud.com/showthread.php?t=42786&highlight=water+carbon
https://forum.ih8mud.com/showthread.php?t=45371&highlight=water+carbon
and before you start worrying about hydrolocking, MikeB on this thread says that seafoam can also hydrolock!
https://forum.ih8mud.com/showthread.php?t=42786&highlight=water+carbon
I believe that there are a few misconceptions regarding the characteristics attributed to octane in this thread. In particular, the misconception that high octane fuel burns slower and results in more carbon due to incomplete burn. Octane is a measurement of a gasoline formulation's resistance to detonation. Detonation occurs, when due to pressure of compression, the fuel self ignites explosively. High octane fuel is more resistant to detonation. It is not necessarily true that high octane fuel burns slower or less completely than low octane fuel. Generally speaking, the burn rate of the fuel, when combusting normally, is independent of the octane.
I thought the 1fzfe was considered a high compression engine?
fzj80kidpen said:Gentlemen,
Seems we all have it.
Nope not all, no ping here
but as stated earlier I run 93 octane.Rich I disagree on the burn rate, higher octane fuel does burn slower, If I had not already packed my school books I would give you a reference.
As for more deposits with higher octane fuel the first I heard of it was in the other thread, but it is one possible explanation of my overly high compression.
Maybe the occasional detonation of lower octane gas flakes off some of the carbon, if so not a very safe way to clean an engine,
Raven, my readings from fuel industry professionals contradict that octane and burn rate are inherently tied together. Each can be indepedently controlled in a gasoline formulation. Generally speaking, better performance is possible with faster burn rates, provided that octane is sufficiently high to prevent detonation. High octane racing fuels are a good example of high burn rates and high octane.
I did some reading on octane and burn rates, and Rich is --correct. For practical purposes, the burn rate of all octane fuels is the same; so my earlier statement about this is incorrect. (There is a relationship between octane and burn rate, but it's not a result of the octane--it's related to the additives which just happen to go along with the octane).
However, I don't think I'm wrong (sounds familar to some political junkies , huh? ). Back in the days of carbs, the a/f ratio wasn't controlled well and running a rich engine would "soak" the carbon deposits with gas and cause engine run-on or predetonation. These days, fuel injected systems are pretty accurate in delivering the right mixture to an engine under all conditions. But the accuracy of the computer/injector delivery system assumes you are using the recommended octane fuel.
If your engine is built for 87 octane and you run 93 octane, you can send too much unburned fuel into the emissions system (including the catalytic converter). I suspect, though don't find any reference to the possibility that this may burn incompletely and form carbon deposits in the engine. But it makes sense to me. In the end, it just doesn't make sense to burn premium fuel unless you're engine is knocking.
However, I don't think I'm wrong (sounds familar to some political junkies
, huh? ). Back in the days of carbs, the a/f ratio wasn't controlled well and running a rich engine would "soak" the carbon deposits with gas and cause engine run-on or predetonation. These days, fuel injected systems are pretty accurate in delivering the right mixture to an engine under all conditions. But the accuracy of the computer/injector delivery system assumes you are using the recommended octane fuel. If your engine is built for 87 octane and you run 93 octane, you can send too much unburned fuel into the emissions system (including the catalytic converter). I suspect, though don't find any reference to the possibility that this may burn incompletely and form carbon deposits in the engine. But it makes sense to me. In the end, it just doesn't make sense to burn premium fuel unless you're engine is knocking.
So now i'm starting to get a bit confused............the motor was designed for 87 octane so that is what should be run, however running higher octane fuels could lead to the motor becoming dependant on it and therefor causing a ping or spark knock when not using it?
My major, though perhaps understated point, is that I don't believe that running premium fuel is, in and of itself, due to burn rate, or other factors, going to result in carbon build up and unburnt fuel going through the exhuast system.
Other engine problems could result in the problems above, but I wouldn't expect carbon buildup or unburnt fuel issues to be attributable to the use of any normal, US quality fuel, premium or otherwise.
So I wouldn't be looking at use of premium fuel as being the root of problems being discussed in this thread, other than perhaps a thinner wallet.
Other engine problems could result in the problems above, but I wouldn't expect carbon buildup or unburnt fuel issues to be attributable to the use of any normal, US quality fuel, premium or otherwise.
So I wouldn't be looking at use of premium fuel as being the root of problems being discussed in this thread, other than perhaps a thinner wallet.
I guess you have a better fuel over your end of the world.... maybe. I think a lot of our fuel is sourced from Malaysia from what I am led to believe.
Here in Oz, our Unleaded is often (By unscrupulous gas station owners) diluted with ethanol, which is pretty cheap, so the gas station owners make a bigger profit.
Therefore, often when the engine pings it is of the result of lower octane fuel because of the dilution.
Many of us here use 97 octane and get better gas mileage from a tank full which eliminates any pinging and works out about the same price in the end.
The pinging we are all talking about is probably not from the result of inadequate fuel, however I just had a thought and thought I would share it, that's all.
Here in Oz, our Unleaded is often (By unscrupulous gas station owners) diluted with ethanol, which is pretty cheap, so the gas station owners make a bigger profit.
Therefore, often when the engine pings it is of the result of lower octane fuel because of the dilution.
Many of us here use 97 octane and get better gas mileage from a tank full which eliminates any pinging and works out about the same price in the end.
The pinging we are all talking about is probably not from the result of inadequate fuel, however I just had a thought and thought I would share it, that's all.
If you suspect carbon build up, there are a few products out there to say the least. The only one I'm aware of that has been scientifically proven to remove cylinder deposits is Techron. I use Amoco (contains a bit of techron) whenever I can, and put a concentrate bottle once a year in my 80. This has been done since the car was new. I also use premium whenever I'm towing or on a road trip and laden in hot weather. I've never heard my 93 ping despite probably the hardest use of anyone on this list (hot weather towing a 6000lb trailer with pedal floored at 20-25mph for several minutes sometimes).
On the other hand, I have heard the '97 ping a couple times on light throttle applications but it's only what I'd term transient ping that lasts only long enough for the knock sensor to adjust the timing. By this I mean perhaps a half dozen quick light pings that stop in less than a second. This was when I bought it a few months ago. Now that I've gone through it with Techron, put new factory NGK plugs in it and a Toyota rotor and cap I have not heard it at all. This despite the current weather now much hotter than when I did hear it. I live in a state that does not require oxygenated gasoline, or any of the various flavors of gasoline required in many metropolitan areas these days. This is something to consider in tracking the issue down - wonder how many of you live in these areas and the fuel takes a dump in terms of burn rate, etc about now to prevent summer smog?? And if people who live in unmolested gas states like me are uniformely NOT having the ping?
Last year, I tried Redline fuel system cleaner on my boat, my Subaru, the 93 80, and my 7.4L boat and got good results. See this thread https://forum.ih8mud.com/showthread.php?t=21289&page=1&highlight=Redline
Personally I'm in favor of the cheap attempts to fix first. So my suggestion would be:
A bottle of Techron concentrate (don't get the regular stuff) in a tank.
Repeat
A bottle of Redline fuel system cleaner in the third tank (claim to fame is other additives leave/move some deposits to valves, and Redline specifically goes after these).
Change the oil (loosened crud ends up in the oil from the Techron).
That's about $30 worth of stuff, but nothing compared to part replacement, and it may clean up the cylinder environment while you don't even open your tool box. I suspect that most of us own 80s someone else put perhaps 100k miles on, plus these are gas pigs, which leads to the possibility a lot of cheap gas went through them and we all know people neglect LandCruiser maintenance believing they're invincible. The combo of old plugs and poor gas may mean several of you have some serious cylinder buildup. Yet the 1FZ is robust enough to continue operating with nary a symptom.
BTW, the best way to use Techron is around town errand type driving. It works by soaking into cylinder deposits after shutdown. When you restart, the outer layer of the crud is flammable and burns off or is knocked off thermally when it ignites. So, don't put it in for a long road trip as it will be underutilized.
As an overall comment, I'm far more likely to believe this is a cylinder deposit situation than so many of you have the same component failing or software error in your engine's ignition mapping system.
DougM
On the other hand, I have heard the '97 ping a couple times on light throttle applications but it's only what I'd term transient ping that lasts only long enough for the knock sensor to adjust the timing. By this I mean perhaps a half dozen quick light pings that stop in less than a second. This was when I bought it a few months ago. Now that I've gone through it with Techron, put new factory NGK plugs in it and a Toyota rotor and cap I have not heard it at all. This despite the current weather now much hotter than when I did hear it. I live in a state that does not require oxygenated gasoline, or any of the various flavors of gasoline required in many metropolitan areas these days. This is something to consider in tracking the issue down - wonder how many of you live in these areas and the fuel takes a dump in terms of burn rate, etc about now to prevent summer smog?? And if people who live in unmolested gas states like me are uniformely NOT having the ping?
Last year, I tried Redline fuel system cleaner on my boat, my Subaru, the 93 80, and my 7.4L boat and got good results. See this thread https://forum.ih8mud.com/showthread.php?t=21289&page=1&highlight=Redline
Personally I'm in favor of the cheap attempts to fix first. So my suggestion would be:
A bottle of Techron concentrate (don't get the regular stuff) in a tank.
Repeat
A bottle of Redline fuel system cleaner in the third tank (claim to fame is other additives leave/move some deposits to valves, and Redline specifically goes after these).
Change the oil (loosened crud ends up in the oil from the Techron).
That's about $30 worth of stuff, but nothing compared to part replacement, and it may clean up the cylinder environment while you don't even open your tool box. I suspect that most of us own 80s someone else put perhaps 100k miles on, plus these are gas pigs, which leads to the possibility a lot of cheap gas went through them and we all know people neglect LandCruiser maintenance believing they're invincible. The combo of old plugs and poor gas may mean several of you have some serious cylinder buildup. Yet the 1FZ is robust enough to continue operating with nary a symptom.
BTW, the best way to use Techron is around town errand type driving. It works by soaking into cylinder deposits after shutdown. When you restart, the outer layer of the crud is flammable and burns off or is knocked off thermally when it ignites. So, don't put it in for a long road trip as it will be underutilized.
As an overall comment, I'm far more likely to believe this is a cylinder deposit situation than so many of you have the same component failing or software error in your engine's ignition mapping system.
DougM
A footnote, for what it's worth.
The Wulf advanced his baseline timing on his 97 some time back. I had the pleasure of having him and his family join us at Lake Powell a couple years ago (I can't think of anyone better to go with ). We were camped at the base of a challenging sand hill, right on the water. Our 80's were the only vehicles that could get down that close to the water and still be able to escape 
. It was a hard charge up a steep sand incline to get out. It was low range and locked at both ends to claw one's way out. Pristine was on a diet of 87 octane and she rattled like a coffee can full of marbles under that load on the climb out. Interestingly enough Beo could not hear the knock in the cabin but I clearly heard it as I spotted/watched him climb out.
D-
The Wulf advanced his baseline timing on his 97 some time back. I had the pleasure of having him and his family join us at Lake Powell a couple years ago (I can't think of anyone better to go with
). We were camped at the base of a challenging sand hill, right on the water. Our 80's were the only vehicles that could get down that close to the water and still be able to escape . It was a hard charge up a steep sand incline to get out. It was low range and locked at both ends to claw one's way out. Pristine was on a diet of 87 octane and she rattled like a coffee can full of marbles under that load on the climb out. Interestingly enough Beo could not hear the knock in the cabin but I clearly heard it as I spotted/watched him climb out.D-