fuel type
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joegr
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That's been greatly debated here. My opinion is that yes you could damage it with low octane gas. If you can't put 91 octane gas in it, then you bought the wrong car. Go to Autozone or somewhere similar and get them to read out the OBDII code to you. Post it here for help. (Post the code, not what the store claims that it means.)
Lincoln Jealous
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have you tried reading your owner's manual?
If it says to use premium, my advice is to use premium. If it says regular, use regular.
the higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.
The majority of cars are designed to run on regular gas, and that's what the manuals tell the owners to use. Higher-performance cars often require midgrade or premium gas because their engines are designed for higher compression (higher compression = more power), and regular gas may cause knock. If your car needs high-octane gas, the manual will say so.
If it says to use premium, my advice is to use premium. If it says regular, use regular.
the higher octane rating means the fuel is less likely to cause your engine to knock or ping. Knock, also known as detonation, occurs when part of the fuel-air mixture in one or more of your car's cylinders ignites spontaneously due to compression, independent of the combustion initiated by the spark plug. (The ideal gas law tells us that a gas heats up when compressed.) Instead of a controlled burn, you get what amounts to an explosion--not a good thing for your engine. To avoid this, high-octane gas is formulated to burn slower than regular, making it less likely to ignite without benefit of spark.
The majority of cars are designed to run on regular gas, and that's what the manuals tell the owners to use. Higher-performance cars often require midgrade or premium gas because their engines are designed for higher compression (higher compression = more power), and regular gas may cause knock. If your car needs high-octane gas, the manual will say so.
what if i fill up with regular gas and and add an octane booster will that help cause here in el paso tx we have regular, plus and super unleaded and super unleaded is the 91 octane and its like 30 more cents than regular, and the car hasnt made a ping or knock yet
Lincoln Jealous
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How to make your own octane booster.
Things You'll Need:
* An empty quart container
* An empty half pint container(for ease of measuring)
* A small funnel
* 1 gallon acetone
* 1 gallon xylene
* 1 quart good quality synthetic 2-cycle oil.
* (All the above ingredients I found at a local Home Depot)
Obtain your supplies from a hardware store. The Synthetic 2-cycle oil may have to be obtained at an auto parts store, but I have found it in the lawn & garden section of most hardware stores. The acetone, and xylene are both paint thinners, so they are in the paint section. Xylene is a component already added to gasoline for stability, and acetone cleans build up and breaks down the covalent bonds in petrol. The 2-cycle oil helps upper end lubrication of the engine, and stabilized burn a little also.
Step 2
The mix ratio is 2:1:1 acetone/xylene/oil, respectively. For ease of mixing use the half pint container, plastic, cleaned out of original contents of course, and fill it with acetone pour with funnel into the quart container(oil bottles are perfect), do this twice. Now fill it once with xylene, pour into quart, and again with the 2-cycle synthetic oil. 1/2pint x 4 = Quart of homemade octane booster.
Step 3
Add 3oz. of your booster to 10 gallons of gas.
i still recommend paying the extra money for the super, we all have to do it, if you cant afford the price of gas, you wont be able to afford to fix the car if it messes up.
Lincoln Jealous
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Lincoln Jealous
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no its means you change your downstream sensor
Outkast
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downstream would be closest to the rear
Lincoln Jealous
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(passenger side)
owlman
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Lincoln Jealous
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but.... used LSes are cheap!
alittle too cheap, we can buy them just to part it out
twinbopilot
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Running regular unleaded should not have fragged your cat. Something else is going on there....
Quik LS
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it likely caused mis-fires (since the octane rating was too low) - which then cause the cat issue.
think about it.
you saved $0.30 a gallon. 18 gallons a fillup = $5.40. the average person drives 20,000miles a year = 17/mpg = $352/year. for less than $30/month - it hardly seems worth it.
think about it.
you saved $0.30 a gallon. 18 gallons a fillup = $5.40. the average person drives 20,000miles a year = 17/mpg = $352/year. for less than $30/month - it hardly seems worth it.
twinbopilot
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The engine is programmed to retard the timing if it senses pre-detonation. I've noticed that if I fill up on Regular 87 after having run Super 93, the first few times I punch it I get some pinging. After maybe 3x, the pinging stops. The computer has adjusted to the fuel by retarding the timing. This is the way it is supposed to work.
Quik LS
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that is correct - but it has a tolerance limit, and it is only effective in a very basic way.
wiki explains octance rating well -> http://en.wikipedia.org/wiki/Octane_rating
here is a good write-up on detonation and pre-ignition - > http://www.lincolnvscadillac.com/showthread.php?t=48616
if there is any unburnt fuel getting into the cat, it will superheat and melt.
when in closed-loop (not WOT) the PCM uses the O2 sensors to determine the AFR and makes adjustments. The spark is part of the equation.
when in open-loop (WOT) the PCM uses tables for AFR - and ignores the O2 sensors. Although the knok sensors come into play, it's usually too little too late.
Remember - it has to start knocking before the PCM can sense it and 'try' to prevent it. meaning you already have the issue before it is corrected, and damage may have already occurred. Like most cars, the LS can mildly misfire a lot before the CEL turns on.
The LS is tuned at WOT for Lean-Best-Torque (LBT) fuel (approximately 12:1 air/fuel ratio, compared to the normal stoichiometric 14.6:1). Spark is normally the minimum of Minimum-for-Best-Torque (MBT) and "borderline" (the spark level at which knock begins occurring). Running closer to MBT when you are borderline limited would mean running higher octane fuel, and since the LS already runs on premium, so you're going to need to find some really good fuel - hence have to go up in octane rating - and bad to go lower.
wiki explains octance rating well -> http://en.wikipedia.org/wiki/Octane_rating
here is a good write-up on detonation and pre-ignition - > http://www.lincolnvscadillac.com/showthread.php?t=48616
if there is any unburnt fuel getting into the cat, it will superheat and melt.
when in closed-loop (not WOT) the PCM uses the O2 sensors to determine the AFR and makes adjustments. The spark is part of the equation.
when in open-loop (WOT) the PCM uses tables for AFR - and ignores the O2 sensors. Although the knok sensors come into play, it's usually too little too late.
Remember - it has to start knocking before the PCM can sense it and 'try' to prevent it. meaning you already have the issue before it is corrected, and damage may have already occurred. Like most cars, the LS can mildly misfire a lot before the CEL turns on.
The LS is tuned at WOT for Lean-Best-Torque (LBT) fuel (approximately 12:1 air/fuel ratio, compared to the normal stoichiometric 14.6:1). Spark is normally the minimum of Minimum-for-Best-Torque (MBT) and "borderline" (the spark level at which knock begins occurring). Running closer to MBT when you are borderline limited would mean running higher octane fuel, and since the LS already runs on premium, so you're going to need to find some really good fuel - hence have to go up in octane rating - and bad to go lower.
According to a notice Ford sent to the dealers several years ago, 91+ is required in the LS's 3.9L V8, although the manual, sticker on the gas cap door, etc, all say 91+ is "recommended."
Around here, 91 runs ~$0.20/gallon more than 89. If I run the tank dry and fill it to the brim, that amounts to a difference of $3.60; if you're paying an extra $0.30 for 91, that amounts to a whopping $5.40. I haven't looked at octane boosters recently, but I'd think a bottle from a trustworthy source would cost you at least as much as just buying the 91 at the pump. If you don't run the car 'til it's on fumes, it's even more of a losing proposition, and it's inconvenient, to boot.
Around here, 91 runs ~$0.20/gallon more than 89. If I run the tank dry and fill it to the brim, that amounts to a difference of $3.60; if you're paying an extra $0.30 for 91, that amounts to a whopping $5.40. I haven't looked at octane boosters recently, but I'd think a bottle from a trustworthy source would cost you at least as much as just buying the 91 at the pump. If you don't run the car 'til it's on fumes, it's even more of a losing proposition, and it's inconvenient, to boot.
He's in the high desert (El Paso's elevation is over 3700 ft); 93 likely isn't easy to find, and isn't really necessary. If he went down to Dallas, he could find it all day long, but he'd burn it all up before he got back to El Paso.
drag214
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He's in the high desert (El Paso's elevation is over 3700 ft); 93 likely isn't easy to find, and isn't really necessary. If he went down to Dallas, he could find it all day long, but he'd burn it all up before he got back to El Paso. [/QUOTE]
Yeah. Out here in Southern Cali, I can't get anything over 91 octane at the pump .
[/QUOTE]Yeah. Out here in Southern Cali, I can't get anything over 91 octane at the pump .
twinbopilot
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Just as an aside, I have owned a few Cadillacs with the Northstar engine. Cadillac went the opposite direction from Ford - The original Northstars required premium, but around 2000 they changed to "Premium Recommended" as they do today in 2009. My current Northstar Deville has 150K, runs great, and hardly ever sees premium. But there are probably design differences I'm not aware of between the Ford 3.9 V8 and Cadillac 4.6 Northstar.
Quik LS
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the other point to remember - if in fact the PCM has to pull timing to prevent knock - you loose performance and likely mpg. So although you may have savesd a bit at the refill pump, you lost some performance mileage.