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My 1st ody was a 99 exl it had 298k on it. had severe carbon buildup issues with egr and plenum passages . I would say that use of non ethanol 91 octane would burn cleaner and thus cause less carbon buildup. Thoughts ?
 

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My 1st ody was a 99 exl it had 298k on it. had severe carbon buildup issues with egr and plenum passages . I would say that use of non ethanol 91 octane would burn cleaner and thus cause less carbon buildup. Thoughts ?
A redline a day keeps the mechanic away. Because a 99 odyssey is not direct injected, just floor it once in a while; fuel should clean the carbon up.
 

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High octane gas is not the recommendation for Honda’s and any extra performance would not outweigh the cost difference. Perhaps the benefit is imagined.
If a vehicle is not designed to utilize the increased anti-knock qualities from premium gas, you won't notice a power increase from using the higher octane. If someone thinks they can tell the difference, it's because of the placebo effect. When I was a kid my car always ran faster after an oil change. What you may get from premium fuel is an enhanced additive package, which may or may not be of benefit to your vehicle.

Why would one want to increase an Odyssey's performance by a few horsepower that no one can actually feel or measure, unless you are going to the drag strip with your Odyssey? If you did race it, you would probably find there is more difference from day to day weather changes and track surface than there is from an increase in power by using higher octane fuel in an engine designed for regular gas.
 

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My 1st ody was a 99 exl it had 298k on it. had severe carbon buildup issues with egr and plenum passages . I would say that use of non ethanol 91 octane would burn cleaner and thus cause less carbon buildup. Thoughts ?
Premium gas has an enhanced additive package but that won't affect your power output. Save your money, and put it into Chevron with Techron or Chemtrol B12 every year or so. From what I have seen, those additives work. Most don't.

These early six cylinder Odysseys all had this EGR coking problem, which was fixed with a service bulletin. The EGR port would get clogged with carbon. The service bulletin called for drilling out the passage in the intake manifold and inserting a tube in the drilled passage, and replacing the EGR valve. I took my 2000 in at maybe 77k for this fix. At maybe 150k it happened again - same code, same problem. This time I did the work. I found that the passage in the intake manifold had never been drilled out, and therefore, the tube had never been inserted. The EGR valve was replaced at that time.

(And - at that time the dealer tried to charge me for reading out and cancelling several anti-lock brake codes that originated from a computer glitch, and they wanted $800 diagnose and fix the problem! They wouldn't give me my car back unless I paid the $40 code reader fee. So I asked to borrow one of their phones and called 9-1-1. I got my car back almost immediately. Nothing was wrong with the brakes.

When I brought the intake manifold back to the dealer several years later, all coked up, with the original receipt, they at first refused to even look at the manifold. Then, days later the Service Manager and the General Manager and I got together. Good guy, bad guy - at first. Then the good guy turned bad guy and said, "If you think we're just going to up and give you $180 worth of parts, you're (expletive deleted) crazy". My next Odyssey came from elsewhere. So did my neighbor's Odyssey.

So - I drilled out the hole (without the tube insert) and put the replacement EGR valve back with a gasket I made (damned if I was going to buy one from the dealer at that point), and it ran happily ever after.

From fifty years of fixing cars for my friends (and myself) in this area, and hearing their stories and experiences, I wonder how an average person with little to no understanding copes with dishonest dealers. They don't - they PAY! Maybe it's because we are here in South Florida. We have had several good experiences with dealers and repair shops in rural America, but here, you're dog meat.

Knowledge is power, friends.
 

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A redline a day keeps the mechanic away. Because a 99 odyssey is not direct injected, just floor it once in a while; fuel should clean the carbon up.
The 'Italian tune-up' might help to clean of carbon from the valves, but not from the EGR passages. The 4 cylinder 1st gen Ody had the similar problem as the 2nd gen having carbon clogged passages. I find it easy to clean them when or before the code comes up.
And I think you're mistaken about the injection.
 

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Hello all and early happy 4th of July!!!!!!!!
Anyways i work at a mini dealership. Fuel quality is huge in the bmw/mini world .ever since i started there i have only used non ethanol 91octane from kwiktrip .the van loves it and i can absolutely tell the difference in performance. My wife however has a 2001 tahoe and only uses 87 octane garbage. What do you guys use or recommend.
FWIW....I have an '06 EXL and drove it about 5000 miles a few years ago, but 2400 miles was in Canada with 87 octane NO ETHANOL, and 2500 miles was in the US with 87octane WITH ENTHANOL. The terrain traveled and city/hwy blend was about the same in both countries. I found the with NO ETHANOL I got 8% better gas mileage, and I've read that the difference usually ranges between 5%-10% depending on a lot of things like climate, type vehicle, type of driving/driver, terrain, etc. My test was about as even as I could get it. I did not see much performance difference, if any at all.
Regarding octane...that number only describes how much the fuel can be compressed before it is ignited by the spark plug; using a higher octane than is required will not give more "power"; actually you might get less "power". Many owner's manuals (and how many folks actually open these or read then these days - mainly to figure out how to work all the fancy electronics) give a range of octane like has been mentioned here, e.g. 87 or higher. Most of these engines have a knock sensor that when activated will change the timing a bit to compensate. Anyway, a high compression engine needs higher octane fuel so it doesn't prematurely ignite when being compressed more. When put in a 'normal' compression engine (87 oct) it may not ignite properly (or at the correct time in the compression cycle) when required because it's not being compressed enough. Some older engines when badly out of time, and likely with carbon build up would keep running for a short period of time after the ignition switch was turned off, and the term used was "dieseling".
Consider that a diesel engine is not a high performance engine in the normal sense, but it does have a very high compression ratio compared to gas engines. Since diesel engines don't have spark plugs they ignite the diesel fuel just by compression
 

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I use regular , 87 octane, top tier gas. I stick with mostly with BP and Shell. That's what the car is tuned for, so buying higher octane gas is a waste of money. If your wife's car calls only for 87 and it runs fine on 87, she is being smart and saving money.
 

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My 1st ody was a 99 exl it had 298k on it. had severe carbon buildup issues with egr and plenum passages . I would say that use of non ethanol 91 octane would burn cleaner and thus cause less carbon buildup. Thoughts ?
Octane has nothing to do with how "clean" as gas burns. If anything, mehanol burns much cleaner than gasoline, but you don't want that in your car unless you replace most of the fuel system. Get top tier gas with enough octane to make sure you do not get engine knock and you will be fine.
 

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Premium gas has an enhanced additive package but that won't affect your power output. Save your money, and put it into Chevron with Techron or Chemtrol B12 every year or so. From what I have seen, those additives work. Most don't.


Knowledge is power, friends.
What do you mean by premium gas? Do you mean the higher octane fuel or do you mean what is defined by the government as top tier gas? You should ALWAYS use top tier gas. That has all the additives needed to keep modern engines running well for a long time. If by premium you mean higher octane, 91+, that is not needed and is wasting money. Higher octane gas is only as the name implies, higher in octane. There are no miracle additives that "clean" your engine. This Honda engine is not tuned to take advantage of higher octane, so you gain nothing.
 

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As for fuel that you get from Costco or BJ's, The reason why their prices are lower is because they have little to no additives in their fuel. It's the additives that the different name brands add that make s the price difference.

And from personal experience, Costco and BJ's ARE NOT top shelf... They purchase from the cheapest seller at all times, Every tanker they get may say the same thing on the trucks, but those trucks are filled by a different supplier every time.
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I disagree with your assessment of Costco gasoline. It is rated a "Top Tier" gasoline so it contains all the required additives.
 
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