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Discussion Starter #1
Silver's MIL illuminated yesterday and stayed on for the duration of the first trip of the day, intermittant after that.

The car was scheduled for 45K service today and we asked Honda to check out the MIL situation too. Techs retrieved another LAF O2 sensor failure code! It's on order at no charge since David paid $402 for the part and repair in September.

Techs want to contact Honda Techline when the replacement comes in. They think there is something going on with "the heater" part of the sensor. How common is it for these sensors to give out? Could it be a bad parts batch? Silver had the ECM recall fixed and gets Exxon supreme. Needless to say, David is not LAF-ing.
 

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2000 Insight Pre-cat O2 sensor

Honda calls the Pre-cat 5 wire O2 sensor-a LAF-"Lean AIR Fuel" sensor the industry calls it a "wide band 5 wire O2 sensor.It is designed for 100,000 miles life.Do you know the code # that the dealer read for the Mil ?

Unlikely a bad/defective sensor,the use of High Test gas(Exxon Supreme) with a octane # greater than 87 is a likely cause of the problem.Does the O2 sensor have carbon deposites on it?The use of high test gas is a big mistake!,made by a lot of people because of the oil industy advertising!! A engine designer is the one who calls for what gas to use,not a oil company's advertizing!!!!

The Insight is designed to run on 87 octane and runs as designed very well on it.A higher octane fuel burns at a slower rate so as to advoid preignition.In a engine not designed to run on it ,it burns too slowly(flame propergation in the combustion chamber) and causes carbon deposits to form in a engine.The techs may be looking at the carbon deposits on the base of the sensor and thinking the heater is a problem,when it's really a "NUT" behind the wheel problem,because he thinks he knows more than the designer/engineers do, NOT !!!!

Hope's this helps,if anything it should reduce your gas bill.........
 

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Discussion Starter #3
Re: 2000 Insight Pre-cat O2 sensor

tuna1 said:
...The techs may be looking at the carbon deposits on the base of the sensor and thinking the heater is a problem,when it's really a "NUT" behind the wheel problem,because he thinks he knows more than the designer/engineers do, NOT !!!!
Uncalled for and untrue. Thank-you for the earlier info re: what the LAF does and how gasoline octane may affect it, since that is of some use.

Bear in mind that the Honda Insight Owner's Manual states "Your Honda is designed to operate on unleaded gasoline with a pump octane number of 87 or higher". The manual then goes on to describe particular problems with lower octane fuel. We will probably move to Chevron 87. It's looking like the best all-around fuel choice.

I don't know what codes the techs found on this diagnostic run. The earlier sensor drew a P1164. Hope to know more when the replacement comes in and they can work thru the problem.
 

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AFAIK an O2 sensor "heater" code is a result of the micro heater in the tip of the sensor failing open circuit, most often its burned out. But sometimes its a failure further down the line. (i.e. the sensors connector)

The octane / damage confusion continues. :(
Read your owner's manual. ;)

Now if you want to talk about sulphur content and damage...(its been comprehensively discussed too :p )
 

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Sorry,

I use the term "Nut behind the Wheel"(as;nut and bolt=cause and effect) as a alternet for Driver,Operator and when i feel they are at fault at creating a problem.

Sorry you took offence.

There is far too much buying of Premium/High Test gas,because people think they are doing "something special" to and for their auto.When in reality they are hurting their engine with it's use.
 

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And "damage" to a car by using premimum fuel is still very suspect in my mind. Yes there is an undesirable effect _IF_ the octane is too high, but it takes more than 6 points to get there (87-93). Combustion is such a dynamic process that such a blanket statement of "damage" borders on disinformation IMO.

AND in the real world case of 93 vs. 87 it _might_ only present itself _IF_ the car could _not_ automatically adjust the ignition timing for optimal combustion based on engine knock. The Insight _IS_ equipped with a knock sensor and _does_ advance timing accordingly.

Drive in the hyper MPG style and in optimal conditions and the difference in 93 _IS_ reflected in better MPG. Just not enough to offset the additional cost. I've been doing it for 65K miles now, there has been no damage.
 

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What's Your defenition of engine damage????????

Just because you do it, does not make what you state,correct.

I suggest you look at internal deposits in the combustion chambers of an engine designed for/and operated on 87 and one ran on 93 for extended periods.Then report back on what you see.

What i stated was it was hurting the engine. Carbon deposits with the use of 93 octane is self induced; as the carbon deposits build up with use and time.The engine now can make use the 93 octane because of an increase in the compression ratio and hot spots that develop on the carbon surfaces in the combustion chambers.This leads to preignition,because of the heat transfer problems that develop thur the surfaces coated with carbon. Heat loss is greater thur the cleaner surfaces in the combustion chambers operated on 87 octane. 93 octane use; raise combustion temperatures along with higher NOX values,at added cost.Why DO IT?

I am not against lower sulfur content in our fuels if availiable.A lower sulfur content gas used in a Insight results in a SULEV rating,instead of the ULEV. Longer cat life results,which will be a positive payback long term.I also suggest the use of Chevron Techron,added to the tank every 5000 miles,when that tank of fuel will be used in stop and go local travel.Techron works by solvation,and works best when a engine sits after shut down on local trips rather than high speed travel use.
 

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:sigh:

Seems like you've avoided the issue on point, the knock sensor.

There are many _possible_ causes of abnormal carbon build-up. Carbon hot spots causing preignition is a text book example of something rarely seen in most cars. And easily remedied with the use of a detergent additive (water works well ;) For others reading don't try this at home unless your already familiar with the proceedure. And since it will almost never benefit an Insight I'm not going to spend the time explaining it) Too high an octane is low on the list (up to the octane limits we are discussing here). And is a non sequitur for any car equipped with a knock sensor. IMO its also a stretch for _most_ other cars.

Is high octane fuel better :?: , not necessarily. And definitely not without adjustments to the car to take advantage of the increase (the knock sensor).

Knock, Knock :?:

But the argument will continue ad infinitum. Its an issue of preference _NOT_ of damage or disinformation.

The last word is yours. :)
 

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I'm a little worried about the premium fuel vs carbon deposits discussion, and the seemingly apparent help of premium to alleviate the 75 mph surge, or hurky jerky CVT behavior, described in adjacent recent threads. I'd suspect that maybe the surgy behavior relates to some sensor getting confused on the computer "curves", where curve points get moved to higher mph, tweaked by fuel difference?
 

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Discussion Starter #10
Silver's new LAF O2 sensor arrived early this week and techs made the replacement today. All was covered under warranty. The DTC on the repair order says P0135 ( what is this?...didn't find on IC Search...it ought not be a gas cap!). Techs checked for possible associated problems and found none. So far so good and I really hope little Silver can stay out of trouble for a long while now. :)

Thanks all for the lively and informative carbon deposit-high octane debate. I asked Honda straight out if octane could be related to the sensor problem. Their answer was "no", but that the brand of gas very definitely can be. They recommended Chevron first or any major brand, Shell and Exxon included. The miscellaneous "cowboy" brands may be cut with ethanol, lack detergents and contain contaminants so they do pose a potential risk for the sensors.

I'm unlikely to scrounge around looking for sensors and carbon blobs...sounds about as enjoyable as cleaning an oven. :) I'm not a mechanic, so plan to go per the Owner's Manual quote, " Your Honda is designed to operate on unleaded gasoline with a pump octane number of 87 or higher."

Thanks again for the help and advice.
 

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To clarify a couple of points on topic to this thread:

Carbon "smothering" of an O2 sensor is _rare_ and you would have all sorts or driveability "problems" leading up to that point. Should an O2 sensor become contaminated in this way cleaning is a possible solution with a hopeful outcome. In any case it will _not_ set an O2 sensor "heater" code. Such a code is detected by merely "seeing" an open or short circuit on that part of the sensor or its related wiring.

Now for the "controversial" part. ;)

_ALL_ gasoline is the same. :shock: (But TRUE :!: )

Well, almost. :twisted:

There are specific blends based on regional requirements of sulfur vs air quality. And there is a summer / winter blend that adjusts the vapor pressure of the gasoline to inhibit summer vapor lock and improve cold vaporization for winter starting.

The rest of any difference is additive; octane, detergents and the like. Almost literally equivalent to a salt & pepper analogy and food. The additive percentages are that small. But that's what makes it good. :p

Honda and several other manufacturers have researched the additive issues and have granted the title of "Top Tier" to several name brands based on the abilities and compatibilities of the additive packages with their cars.

Other non rated additive packages _may_ be sufficient for long term use without damage. Non detergent gasoline should be avoided (and I don't know where you'd find it).

See:

Problems and Troubleshooting
Engine hesitation
"Top Tier" Gasolines. Tue Aug 31, 2004 4:40 pm
http://www.insightcentral.net/forum/vie ... tier#19331

Links to:

http://www.ahm-ownerlink.com/Maintenanc ... #gasolines.

Thanks to member TomV for posting this.

HTH! :)
 

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After talking with BP after I got my car from them, they spend 4 years developing better cleaner additive packages for their premium fuels.

Since the Insight was used for this process, I use BP exclusively.
However, BP mentioned that Shell did the almost exact same thing a year later, and Chevron as well.

So Insightful Trekker is right on, all fuel is the same, it is refined the same way and comes from the same place.

The only difference is the additive packages, much like motor oil.
Which is far more complicated.

In the Insights case, since we really only have two options for 0w20 it makes it much more simple.
 

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uuuhhh....

You know after reading all this I'm still not sure what gas to get..

I thought the way they market the 94 octane gas it;; as a cleaner burning fuel and its better for performance and the environment is the reason I've been buying it for the insight..... are the gasoline companies... lying about this?

Is the higher octane fuel cleaner burning... according to some of the posts here its not.... so no need to buy it... I'm not sure... any insights?
 

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Octane level has every thing to do with compression ratio of the engine, and nothing to do with anything else. The higher the octane level the slower the burn time. High compression pistons require higher octane levels or there will be pinging of the engine. The Insight does have high compression pistons, and therefore high octane gas would be of benefit. The insight will also compensate for low octane levels, so the 87 octane will work. 89 to 91 octane would be ideal for the Insight IMO, because of the compression ratio. The main problem of using a high octane level gas in a low compression vehicle, is that the will be a carbon build up on the valves and heads, over time and will cause damage.
 

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Dynamic comperssion values _will_ be effected by ignition timing.

[Within limits more "advanced" timing effectively increases the compression value, increasing the combustion temperature and therefore the volumetric efficiency (more power for the same displacement (engine size)).] edit: IIRC I'm pointing in the right direction here but wayy off target and tried to simplify too much. Now after further reflection and realizing all the needed qualifications and further explinations (and retractions) I think I'll try to gracefully back out of this thread. :oops:

From my expereince, when driving in the hyper MPG style I get somewhat better MPG when using 93 octance vs 87. But the cost difference for the increase never pays for itself.

HTH! :)
 

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hmm...

this just gets better and better with people interjecting but not really answering...

EASY question: does the higher octane level in an insight cause a higher build up of carbon? Yes or no?

As most of you know our egr valve isn't that hot, I've had to clean mine out to get rid of that annoying shuddering problem. When I cleaned it out there was lots of carbon in it... so for me I just want to avoid uneccessary build up of the stuff... I've been using the higher octane gas all the time in the car... for the " cleaner burn" but from what I'm hearing here is that its will do just the opposite...

Now someone is right in this thread I just don't know who... higher octane more carbon? yes or no? ....
 

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Sorry,

Its not a yes or no answer. It depends.

On _many_ different factors. And carbon-buildup has readily diagnosable symptoms with various remedies. You'd have to limit the range of your question to something like; "Is the 87-93 octane choice in an Insight a significant factor in relation to carbon build-up to the degree that will require counter measures." IMO no. And from experience even in a non knock sensor equipped car 93 octane is not high enough to cause a "carbon" problem. Do you think that the oil companies would sell a "defective" product of which they could be held liable :?: The tobacco companies thought they could. Millions of cars would be effected. <rhetorical questions>

So far in my Insight I am proving it. 85K miles and only the _rare_ ingestion of anything less than 93 octane. No carbon consequences of any kind, including any EGR hiccups. (so far) But as in all things automotive YMMV.

Carbon soot in an EGR system is a _normal_ consequence of its operation.

Now unless there's something new to add I'd recommend reviewing the extensive discussion existing on this topic rather than repeating what has already been asked and answered.
 

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Well it is a yes or no answer... I finally located a chemist that specializes in fuel... and the short of it is this... octace levels are there not for performance purposes... they are there for engine knocking purposes.. if your car can handle 87 octane that is what you should run.. there will be no performance benefit to higher octance...

So that is the answer phd in chemistry that specializes in fuel said to me and with no partiality. So I'm going to take the advice I was given.

What extensive discussion are you referring to? I don't see anything extensive.
 

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:lol: "Ask" a trauma MD why it hurts in one particular spot an he'll give you a trauma oriented diagnosis.

Yes its true the Insight can handle 87 octane just fine. But as usual the Insight's knock sensor has been left out of the equation that can tweak the engine to perform better with higher octane fuel. And should you drive your Insight in the hyper MPG mode with this "increased" performance you will see a slight MPG gain. Higher MPG = less fuel burned and less of most emmissions per mile. At a slightly higher cost per mile. But so is the choice of an Insight compaired to several other makes and models.

I won't even try to explain the other sublties and complexities that _may_ yield a _LONG TERM_ benefit. At best they will be relatively minor.

87 vs. 93 is a choice. In other cars that can't adjust for the increased "performance" its 99% waste. In the Insight its considerably less. But it has all been said before in past posts. Use the forum search feature if your interested. Google for more authoritative sites with answers.
 

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Where is this search feature? I've looked around for it...

Well no... she did mention the knock sensor thing... but it has to do with preignition detonation and not related to mileage. Though it can adjust with the higher octane... in theory it will not have any performance gain.

I'd be curious to see figures of actual mileage results from users using 87 vs. 94 etc... as for me I'm not a hypermiler and don't think I ever will be... so 87 is good for me.
 
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