Gasoline Octane warning to all.

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adrian36

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I have been using 93 Octane rated gas which I get at a COSTCO near my home. Recently I have noticed that my car was making a gargling sound and pinging under load--- lets say, when you accelerate between 20-30MPH. Also, when you would floor it of the line or when you were about 15 MPH and floored it the sound would manifest itself. I thought the timing was off. I contacted Dennis R. (he flashed my comp on the car) he was very sincere and offered to take a look at it -- Thanks Dennis but I believe the problem may not be the CPU. I ran the car until it was short a 1/4 tank. I went to HESS pumped up about 7.5 gallons and sped off. After about 5 miles or so the car was different, even the exhaust noise was smoother. The pinging was still there but much less and not last as long when you accelerated. I also added a bottle of Techron fuel injection cleaner. Also a buddy of mine gave me 1/2 gallon of VP racing fuel. I refilled today with another 8 gallons of HESS. I still have about 5 gallons or so of that supposedly 93 Octane gas from COSTCO still in the tank. The car is much, much better. The MM is very sensitive to octane ratings. I wonder if Costco just made an honest mistake. I hate to bad mouth anybody, but I know my car. Just be careful people
 
I never buy really expensive gas, but I never buy the cheap crap either...can't be tempted by the $1.70 for Premium stuff. I've noticed it doesn't last as long also...not a huge difference but a difference.
 
woaface said:
I never buy really expensive gas, but I never buy the cheap crap either...can't be tempted by the $1.70 for Premium stuff. I've noticed it doesn't last as long also...not a huge difference but a difference.
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James- with our engines--there is no choice but premium if you want to take care of it---and yes--they( MM engines ) are sensitive to the rating they get---it's not worth it to put in lower octane ......Tom
 
I always use 93 octane mobil gas. I've done that when my MM was N/A, and now that it's S/Ced, I definately will continue to do that. I've never had a problem w/their gas.
 
Octane sensitivity

Even the two valve Crown Vics are sensitive to minor Octane changes. I also had Dennis reflash my ECU and it helped a lot. I do occasionally run 87 (if I am merely running 70-75 down the highway) but the car runs a whole lot better on 93.

Don
 
I used to work for a gasonline distribution company as an electronics repairman.....

It is not unusual for the wrong grade of gas to be dropped into the premium tank, by "accident". Usually, to have it done, the gas station will order too much gas for their 87 or 89 octane tanks, then when the driver notices that it all won't fit into the tank, they will just drop the rest of the order into the premium tank.

Yes, it's illegal, but there is no field test for verifying octane rating, and the chance of getting caught is VERY slim! If records show that the wrong grade was dropped in a tank, the owner just has to say "whoops!" and they just get told to try and make sure it doesn't happen again.

It is a common practice, mainly with the mom & pop type gas stations, because they usually order their gas from the distributor with the lowest prices, plus the distributor who is willing to drop the extra gas in the wrong tank. I've seen it done a few times while working on the electronics in the gas pumps.

Doesn't usually happen at the larger, name brand stations such as Exxon or BP, due to checks and balances that happen to make sure they are not cheating the customers, which would give them a bad name with the customers.


Also....Costco gas has a LOT of sulfur added to it, which is what helps keep the gas price lower. Sulfur doesn't cost very much, and makes a great filler to bring the price down to pass on to the customers, BUT sulfur is not good for a lot of engines, and the cat convertors. Gate fuel is the same way. May be cheap, but I wouldn't run it unless I was on 'E'.

Just my 2 cents......
 
adrian36 said:
I have been using 93 Octane rated gas which I get at a COSTCO near my home. Recently I have noticed that my car was making a gargling sound and pinging under load--- lets say, when you accelerate between 20-30MPH "snip, snip" Just be careful people
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I use only 93 Octane from Exxon or Mobil -- but I guess the same truck now delivers both. I try to stay away from the off-brands because you may not know the true source. Some off- brand independents are able to keep prices low by taking the bottom scraps from tanks when they periodically "empty" their tanks. This stuff has lots of sediment in it and it can be mixed with numerous brands. Can't say for a fact that CostCo does this; but such a practice does go on in those One Off stations.

It might be advertized as 93; but you really have no idea what you are getting. And, it could be loaded with sediment. If you can afford ground beef --- don't use hamburger helper --- unless, of course, you like the taste and performance.
 
Two valve crown vic...yeah that's what I've got. I'm always pumped up on 93 too. But like I said, I won't buy the cheap stuff, it seems to disappear too quick, just a waste of money...I'll drive to the next station if I can make it.
 
Ever since i bought my mm i've only used 94 from sunoco.never had any problems.and when i go s/c i will continue to use it as well.unless dr tells me not too.
 
93 octance form Mobil as often as possible.

But I wonder if it would be a way to save money by going with a less octance and a can of boost with each tank.

Best,

Dan
 
Adrian- I don't think gas for our Marauders should be a low-price decision. :cool4: I like Sunoco because it's 94, the highest I can find, and I trust their brand. Their car washes are pretty good, too. Blender pumps, anyone?
 
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MapleLeafMerc said:
I like Sunoco because it's 94, the highest I can find, and I trust their brand.
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I agree and like Sunoco becuase of the 94 Octane. As of late though Sunoco has only had 93 and a sign that says "Same Quality Fuel." Kinda of sucks if you ask me....
 
Well, toomanyfords decided to not reply here with anything of substance, but he did post something helpful in another thread here, so, I thought I'd bring that over for y'all. It's got to do with this octane thingy, after you step over the wisecracks...
TooManyFords said:
I'd love to Mac, but I didn't write the race fuel program for the SCT tuner so I don't know how it is setup. But, I have a good idea so I'll try to take this slow for ya, Mac...

The higher the octane means the fuel burns SLOWER to prevent things like detonation, pre-ignition, knock and ping. I can only -assume- that the 100 octane program in the tuner uses an advanced ignition timing curve that requires the fuel to burn slower to prevent the above conditions.

Since a tuner cannot change the compression ratio (another big reason to use higher octane), here's what I recommend:

1. Put the 100 octane gas in at least one full tank BEFORE switching to the new racing program. You should make sure that all the pre-100 octane gas is gone or you run the risk of deadly detonation and ping. Remember, your tank holds a gallon or two even when the "your empty" light is lit.

2. Switch to the new program.

3. Immediately switch back to the original program after racing and BEFORE the 100 octane is gone. John
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Maybe John's reply isn't right on focus with us here, but he's explaining something about octane, and how it affects our MMs, and I thought that would be valuable to y'all. Advice about the burn, and burn off, and all. If not, nevermind. I thought John had the answer.

I get my gasoline at Citgo and I pay for my octane. I'd better be getting that too. Moreover, I think it's a shame that the "octane boosters" we get pitched on, are not what they claim to be.

Seems like getting the right octane is like getting sex after marriage. Nothing is what we expect it to be, and we're still chasing after the advertiser wanting more.

(shrug) Oh well...
 
To add to the frustration, it seems that a certain 'X' octane from one manufacturer might not perform the same way as 'X' octane from another. Also, much to my frustration, the same octane grade of fuel from the same manufacturer but from DIFFERENT stations (!) can behave differently! Hence, I have my favorite station and try to stick with it (or 'had', as they recently downgraded to 91 octane, and I can occasionally hear the big girl ping now and again)
 
Way to take the "high-road" John. :up:

I'm getting kinda tired of the pompous, arrogant, napoleonic, multi-paragraph, blow-hard stuff myself, as well. And a response from you pointing out any further flaws in ones "octane theology" that you'd need to address would have certainly invited one.
 
MapleLeafMerc,

Blender Pumps.....Boy, those things make it WAY to easy to cheat customers! When I worked for the fuel company, we were testing these units. Since I worked in the "computer" department for the company, I was involved in the setup of making these pumps work with our automated credit card systems. 90% of our stations were "unattended", where there was nobody to pay, and you had to use a credit card, or a pre-pay card that you would get from our main office.

Anyway, we were playing with the blender pump and found that you could actually alter the amount of blend between grades, while the person was pumping. It would make a VERY easy way to cheat people, if the company wanted to. Each pump had its own mechanical meter, but that is not what the state tests when checking the amount of fuel being delivered. The state only test to see that when the display shows 5 gallons, that the customer actually gets 5 gallons. They didn't check to see that it was of the proper grade or anything.

We didn't cheat anyone with our computer programs, but I could tell you about 5 different ways to cheat the customer, but at the same time, I could tell you 2 different ways to cheat our computer program and get free gas. Basically, we would test ways that we COULD cheat the customer, so that we could put checks in to make sure that some other programmer didn't come in behind us and stick it to the customer.

Anyway, blender pumps were a great new item for us, and we started using them extensively, but it just opened up new cheat options for the gas companies, if they wanted them.
 
TAF said:
Way to take the "high-road" John. :up:

I'm getting kinda tired of the pompous, arrogant, napoleonic, multi-paragraph, blow-hard stuff myself, as well. And a response from you pointing out any further flaws in ones "octane theology" that you'd need to address would have certainly invited one.
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I'm sure glad you were clear about that!!!even though I'm not sure what the hell your saying............Tom
 
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