Pinging under hard acceleration
Thread Starter
Lead Lap
Joined: May 2006
Posts: 3,680
Likes: 302
Pinging under hard acceleration
My 2001 LS430 with 119,000+ miles has the original plugs and does ping intermittently upon hard acceleration. I have changed the gas station a few times and am using 93 octane. Chevron is my favorite station as well. The car idles perfectly, and accelerates as it should. Gas mileage is as crappy as to be expected with all city driving (around 13-14mpg). Would the original plugs be the most likely culprit or could it be something else? I will probably change the plugs as it it close to the mileage anyway. Any feedback would be greatly appreciated. Thanks all.
Another person had this same problem. Replacing the engine temp sensor fixed the issue.... Lol. I'm becoming the temp sensor broken record, but really for good reason. 
Plugs need to be changed but it is not the cause. Incorrect fuel to air ratio because of a failing temp sensor is the cause. Well, I'm willing to bet a $1 that this is the problem. Replace that sensor. My hypothesis is that the electrolysis that happens in the coolant degrades these sensors and causes them to misread the correct engine temperature.
I think everyone should replace this sensor. I have yet to read that it has not helped the car run better. It makes logical sense. Just look at the condition of the old one vs the new. Being only a few degrees off affects the car a lot. I bet your mileage will go up as well.
https://www.clublexus.com/forums/ls4...ml#post8842490
Plugs need to be changed but it is not the cause. Incorrect fuel to air ratio because of a failing temp sensor is the cause. Well, I'm willing to bet a $1 that this is the problem. Replace that sensor. My hypothesis is that the electrolysis that happens in the coolant degrades these sensors and causes them to misread the correct engine temperature.
I think everyone should replace this sensor. I have yet to read that it has not helped the car run better. It makes logical sense. Just look at the condition of the old one vs the new. Being only a few degrees off affects the car a lot. I bet your mileage will go up as well.
https://www.clublexus.com/forums/ls4...ml#post8842490
Last edited by Lavrishevo; Jul 5, 2015 at 08:22 PM.
Driver
Joined: May 2015
Posts: 141
Likes: 3
From: GA
Another person had this same problem. Replacing the engine temp sensor fixed the issue.... Lol. I'm becoming the temp sensor broken record, but really for good reason.
Plugs need to be changed but it is not the cause. Incorrect fuel to air ratio because of a failing temp sensor is the cause. Well, I'm willing to bet a $1 that this is the problem. Replace that sensor. My hypothesis is that the electrolysis that happens in the coolant degrades these sensors and causes them to misread the correct engine temperature.
I think everyone should replace this sensor. I have yet to read that it has not helped the car run better. It makes total sense. Just look at the condition of the old one vs the new. Being only a few degrees off affects the car a lot. I bet your mileage will go up as well.
https://www.clublexus.com/forums/ls4...ml#post8842490
Plugs need to be changed but it is not the cause. Incorrect fuel to air ratio because of a failing temp sensor is the cause. Well, I'm willing to bet a $1 that this is the problem. Replace that sensor. My hypothesis is that the electrolysis that happens in the coolant degrades these sensors and causes them to misread the correct engine temperature.
I think everyone should replace this sensor. I have yet to read that it has not helped the car run better. It makes total sense. Just look at the condition of the old one vs the new. Being only a few degrees off affects the car a lot. I bet your mileage will go up as well.
https://www.clublexus.com/forums/ls4...ml#post8842490
Driver
Joined: May 2015
Posts: 141
Likes: 3
From: GA
Lexus Test Driver
Joined: Mar 2007
Posts: 1,025
Likes: 13
From: McAllen, TX
Pinging under hard acceleration
I replaced my temp sensor and did see some reduction in pinging, but my pinging problem hasn't been eliminated yet. Wondering if there's some other sensor that could be worn. Oxygen sensors maybe?
Did you check and / or replace your pcv valve as well? Also, are you positive what you are hearing is pinging and not something else? Pinging should always be worse under load and when the temperature is hot.
What Is Engine Pinging?
"Pinging" is the metallic rattling sound an engine can make when accelerating. It usually occurs when the vehicle pulls away from a stop and the engine is under a lot of load.
When an engine pings, it releases pollution into the environment in the form of nitrogen oxide (NOx) and raw, unburned hydrocarbons (HCs). These two chemicals are poisonous gases that show up as yellowish-brownish in a polluted sky. They can also cause respiratory problems like asthma and emphysema—a pinging engine is never a good thing.
Common Reasons for Engine Pinging
Improper Combustion Process
An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). In a properly-firing cylinder, the spark plug ignites the air/fuel mixture and a flame front starts on one side of the piston and burns across the top to the other side, which creates a rapid and evenly-expanding gas that pushes down on the top of the piston. When the air/fuel mixture is ignited prior to the spark plug firing, the two flame fronts collide, causing the pinging/knocking noise.
Engine Is Too Hot
An engine can ping because it is too hot. This is another uneven combustion scenario that is caused by the air-to-fuel mixture "lighting off" by itself. If the cooling system does not keep the engine's combustion chamber temperature in check, the air-to-fuel mixture will begin to spontaneously explode. This is also called "pre-ignition."
Improper Gasoline Octane
In addition to cooling system problems, pinging can be caused by improper gasoline octane, an overly lean air-to-fuel mixture, or a lack of proper exhaust gas recirculation. The exhaust gas recirculation system (EGR) was created to neutralize engine pinging by adding a small amount of exhaust gas to the air-to-fuel mixture going in to the combustion process, which limits the peak combustion chamber temperature.
"Pinging" is the metallic rattling sound an engine can make when accelerating. It usually occurs when the vehicle pulls away from a stop and the engine is under a lot of load.
When an engine pings, it releases pollution into the environment in the form of nitrogen oxide (NOx) and raw, unburned hydrocarbons (HCs). These two chemicals are poisonous gases that show up as yellowish-brownish in a polluted sky. They can also cause respiratory problems like asthma and emphysema—a pinging engine is never a good thing.
Common Reasons for Engine Pinging
Improper Combustion Process
An engine can ping (or knock) due to an improper combustion process. A "spark knock" is the result of combustion occurring too early. Early combustion can occur from carbon buildup inside the combustion chamber, a lean air/fuel mixture, and advanced ignition timing (spark plug firing too soon). In a properly-firing cylinder, the spark plug ignites the air/fuel mixture and a flame front starts on one side of the piston and burns across the top to the other side, which creates a rapid and evenly-expanding gas that pushes down on the top of the piston. When the air/fuel mixture is ignited prior to the spark plug firing, the two flame fronts collide, causing the pinging/knocking noise.
Engine Is Too Hot
An engine can ping because it is too hot. This is another uneven combustion scenario that is caused by the air-to-fuel mixture "lighting off" by itself. If the cooling system does not keep the engine's combustion chamber temperature in check, the air-to-fuel mixture will begin to spontaneously explode. This is also called "pre-ignition."
Improper Gasoline Octane
In addition to cooling system problems, pinging can be caused by improper gasoline octane, an overly lean air-to-fuel mixture, or a lack of proper exhaust gas recirculation. The exhaust gas recirculation system (EGR) was created to neutralize engine pinging by adding a small amount of exhaust gas to the air-to-fuel mixture going in to the combustion process, which limits the peak combustion chamber temperature.
Last edited by Lavrishevo; Jul 6, 2015 at 05:32 AM.
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Lexus Test Driver
Joined: Mar 2007
Posts: 1,025
Likes: 13
From: McAllen, TX
Yep its definitely pinging/engine knock. Kinda bummed because I thought I had the problem fixed when I replaced that temp sensor. Before the temp sensor change, I could be driving at higher revs and stab the gas and it would knock terribly. I would get intermittent bad episodes of knocking here and there under different conditions. Now it doesn't do that nearly as bad but it does knock at lower rpm's mostly, and more or less throughout the rpm range. My O2 sensors are original and haven't thrown any codes, but who's to say they are actually measuring the gasses correctly. I dunno. Hopefully this week a can get a buddy to help me do the water decarbonisation trick and see if that helps. I did replace the PCV valve a few months ago also, it was a little dirty but still functioning.
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Lexus Test Driver
Joined: Mar 2007
Posts: 1,025
Likes: 13
From: McAllen, TX
Lexus Test Driver
Joined: Mar 2007
Posts: 1,025
Likes: 13
From: McAllen, TX
No CELs. Never noticed a problem with the plug wires myself, techs never mentioned anything about them either. Had the TB and valve covers/cam seals/plug seals etc done six months ago so if they were bad I suspect the tech would have said something. Pinging has been a problem for at least 2-3 years.
Lexus Champion
Joined: Mar 2011
Posts: 2,186
Likes: 728
From: Texas
It could be bad OCV (Camshaft Timing Oil Pressure Control Valves). A failed OCV will give you a DTC, but I'm not sure if a "failing" or slow one would do the same. Check out this post for more details...
https://www.clublexus.com/forums/ls-...ocv-valve.html
https://www.clublexus.com/forums/ls-...ocv-valve.html
Pole Position
Joined: Mar 2008
Posts: 2,146
Likes: 70
From: Illinois
I considered the OCVs too, however as mentioned, you would get a P1354 (passenger side) or P1349 (driver's side) CEL code. And by now, 2-3 years, a CEL would have lit for this. https://www.clublexus.com/forums/ls-...lfunction.html.
Last edited by Tom57; Jul 6, 2015 at 01:38 PM.
Pole Position
Joined: Mar 2008
Posts: 2,146
Likes: 70
From: Illinois
No CELs. Never noticed a problem with the plug wires myself, techs never mentioned anything about them either. Had the TB and valve covers/cam seals/plug seals etc done six months ago so if they were bad I suspect the tech would have said something. Pinging has been a problem for at least 2-3 years.
