I replaced the spark plugs in my 2009 Acura MDX last week at 106K miles. I was a little disappointed that the plugs coming out didn't look as good as some other plugs I have changed on my Hondas over the years. These showed some slight brownish discoloration. Others I have changed in the past looked almost pristine. Additionally, about half the coils were brown/burnt looking. The other half looked a dark gray, which I believe is the normal color. My question is should I replace any or all of the coils? I am experiencing no issues, so my default is to not do anything. But I am wondering if I am missing an increase in performance or MPG, or if the new plugs are being damaged by the brown/burnt coils. Any thoughts are appreciated. Thanks.
New coils needed?
- Thread starter cwing6
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You are experiencing no problems. Just make sure the plugs are gapped properly and all connections are tight and keep your money. The brown color of the plugs is probably a result of something in the fuel.
Originally Posted By: WobblyElvis
You are experiencing no problems. Just make sure the plugs are gapped properly and all connections are tight and keep your money. The brown color of the plugs is probably a result of something in the fuel.
This vehicle requires premium unleaded. One thought that crossed my mind was the previous owner may have just used regular, causing the discoloration. Supposedly this does not affect the engine long-term, but reduces horsepower and creates rough idle.
You are experiencing no problems. Just make sure the plugs are gapped properly and all connections are tight and keep your money. The brown color of the plugs is probably a result of something in the fuel.
This vehicle requires premium unleaded. One thought that crossed my mind was the previous owner may have just used regular, causing the discoloration. Supposedly this does not affect the engine long-term, but reduces horsepower and creates rough idle.
Originally Posted By: cwing6
Originally Posted By: WobblyElvis
You are experiencing no problems. Just make sure the plugs are gapped properly and all connections are tight and keep your money. The brown color of the plugs is probably a result of something in the fuel.
This vehicle requires premium unleaded. One thought that crossed my mind was the previous owner may have just used regular, causing the discoloration. Supposedly this does not affect the engine long-term, but reduces horsepower and creates rough idle.
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
Originally Posted By: WobblyElvis
You are experiencing no problems. Just make sure the plugs are gapped properly and all connections are tight and keep your money. The brown color of the plugs is probably a result of something in the fuel.
This vehicle requires premium unleaded. One thought that crossed my mind was the previous owner may have just used regular, causing the discoloration. Supposedly this does not affect the engine long-term, but reduces horsepower and creates rough idle.
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
Originally Posted By: Donald
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
The OP's car has an engine with a 300hp, high compression V6. In fact, it is one of the most powerful Honda engines ever sold in a production car. Premium is required by the manufacture in this car. I have a 2010 Acura TSX 2.4 (made by Honda) that has 11:1 compression. The car says 91 octane is recommended, but 87 octane can be used.
This is what the OP's manual actually says:
“Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. If this octane grade is unavailable, regular unleaded gasoline with a pump octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long-term use of regular-grade gasoline can lead to engine damage.”
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
The OP's car has an engine with a 300hp, high compression V6. In fact, it is one of the most powerful Honda engines ever sold in a production car. Premium is required by the manufacture in this car. I have a 2010 Acura TSX 2.4 (made by Honda) that has 11:1 compression. The car says 91 octane is recommended, but 87 octane can be used.
This is what the OP's manual actually says:
“Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. If this octane grade is unavailable, regular unleaded gasoline with a pump octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long-term use of regular-grade gasoline can lead to engine damage.”
Originally Posted By: bubbatime
Originally Posted By: Donald
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
“Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. If this octane grade is unavailable, regular unleaded gasoline with a pump octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long-term use of regular-grade gasoline can lead to engine damage.”
It's funny because most people really don't realize that many cars are designed to run on premium fuel, but due to modern computer engine management systems, they "can" accept regular fuel if "necessary". However, in any car that even hints about premium fuel being recommended or required, it is always best to use premium and follow that recommendation. Even though cars seem to run "fine" on regular where premium is specified, they are actually running with retarded ignition timing because they will knock under acceleration. You don't hear this knocking because the computer immediately retards ignition timing until it stops. The cycle happens over and over again while on regular fuel. Use of regular in these engines leads to reduced efficiency, increased fuel dilution, reduced fuel economy, and other domino effects as a result.
Some cars sold in N/A actually recommend or require premium elsewhere in the world, but only "need" regular here due to marketing reasons and the fact that most won't notice the downsides, especially if they never try the premium fuel.
Originally Posted By: Donald
Does it really "require" or just "prefer". I think it just prefers high test gasoline. It may have more pep with high test but it will run fine with either.
“Your vehicle is designed to operate on premium unleaded gasoline with a pump octane of 91 or higher. If this octane grade is unavailable, regular unleaded gasoline with a pump octane of 87 or higher may be used temporarily. The use of regular unleaded gasoline can cause metallic knocking noises in the engine and will result in decreased engine performance. The long-term use of regular-grade gasoline can lead to engine damage.”
It's funny because most people really don't realize that many cars are designed to run on premium fuel, but due to modern computer engine management systems, they "can" accept regular fuel if "necessary". However, in any car that even hints about premium fuel being recommended or required, it is always best to use premium and follow that recommendation. Even though cars seem to run "fine" on regular where premium is specified, they are actually running with retarded ignition timing because they will knock under acceleration. You don't hear this knocking because the computer immediately retards ignition timing until it stops. The cycle happens over and over again while on regular fuel. Use of regular in these engines leads to reduced efficiency, increased fuel dilution, reduced fuel economy, and other domino effects as a result.
Some cars sold in N/A actually recommend or require premium elsewhere in the world, but only "need" regular here due to marketing reasons and the fact that most won't notice the downsides, especially if they never try the premium fuel.
Exactly. My car requires 93 as well. VQ35 is 270 horse power motor and runs very well on Shell, Exxon, and Sunoco as well. I ran across a nice lady who had a 2014 Maxima with the 3.5 motor. It was so new that it still had temporary tags on it and she said it was running terrible. Running 87 in it. I was like, yeah it supposed t o run on 93. She was like, "which one is that?". It does matter at times with some cars.
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