Ooops! 87 octane.... [Archive] - MercuryMarauder.net Forums

Heavy351

02-19-2004, 07:52 AM

Ok, I'm an idiot. I admit that but feel free to remind me. I would expect nothing less from you..

Late last night at an unfamiliar gas station, I pick up what I thought was the correct nozzle...locked the lever and walked inside desperate for coffee. Turns out I now have a full tank of 87 octane.:rolleyes:

Now in the old days, I would turn the distributor back on my '88 CVPI and not worry about it.

I hear a ever so slight pinging occasionally under moderate throttle. Keeping my foot out of the throttle I am wondering if I shouldn't get all worked up about it and wait to refill the next tank or panic now and top off with super primium at 1/2 a tank.

My understanding is that pinging/detonation is damaging only under serious loads or high RPMs....

Is there a limit to how much the computer can retard the timing?

How does the computer know to advance the timing when I put the good stuff back in?

MARAUDERCHICK

02-19-2004, 08:01 AM

You're not an idiot!! Just human....you are allowed a mistake every now and then....

That's all I can help you with....don't know about the computer stuff!;)

GarageMahal

02-19-2004, 08:07 AM

I am wondering if I shouldn't get all worked up about it and wait to refill the next tank or panic now and top off with super primium at 1/2 a tank?
If you down to half a tank, I would fill it with the highest octane you can find. But that's just my uneducated option.

jta

BillyGman

02-19-2004, 08:09 AM

The computer has a timing retard action that is governed or brought on by a knock sensor. When the engine begins to knock (AKA "ping") then the computer will retard the ingnition a bit until the knocking disappears, but as far as I know it will not keep theignition retarded. The retard action is merely a momentary thing.

If you have a half tank of gas now, then you should go and top it off w/some 93 octane gas and/or you can get some octane booster at a parts store.

FordNut

02-19-2004, 08:19 AM

RF Overlord

02-19-2004, 08:30 AM

^^^what BillyGman said^^^

Except I respectfully disagree with his suggestion of adding an "octane booster"...it's been discussed on a bazillion boards, including this one, that OTC octane boosters do little or nothing (except foul your plugs)...

Unless your engine is knocking heavily, or you are driving like a moron, you haven't done any harm to your motor...just don't do it too often...idiot... ;)

MarauderMark

02-19-2004, 08:39 AM

I had also done the same thing with 87oct (Coastal)without paying any attention.but it really made no difference at all (cruising back and forth from md to pa everyday)and when it got down to 1/2 tank i went to (sunoco )and pumped in 94 oct .which is the only thing i try to use...

Heavy351

02-19-2004, 08:41 AM

I can see it now... the first meet I make it too I'll get "oh so YOU are the one who put 87 in, HEY EVERYBODY THIS IS THE GUY!"

Just hand over the keys now, you have been deemed not worthy....

I appreciate the support Marauderchick, I had to dig deep to post this to the group.....

My brother in law asked me once why his maxima wouldn't go when he put it in gear. He had changed his own oil for the first time.....Turns out he had drained all the tranny fluid and had 10 quarts of oil in the engine.:shake:

If I had done that I could understand my banishment from the group forever.

BillyGman

02-19-2004, 09:16 AM

^^^what BillyGman said^^^

Except I respectfully disagree with his suggestion of adding an "octane booster"...it's been discussed on a bazillion boards, including this one, that OTC octane boosters do little or nothing (except foul your plugs)...

well then, I respectfully concede, cuz I can't say that I've even ever used octane boosters myself. Just a thought I guess. But thanks for not hammering me about it. Your comments were indeed respectful and well taken. ;)

RF Overlord

02-19-2004, 09:41 AM

Gman:

I used to use 104+ Octane Boost in my '68 Buick, as it originally called for 99 octane...their claim was to raise the octane by 4-7 points, so if I was using 92 octane, that should get me mighty close to the requirement. Well...I always wondered why the booster never seemed to work as well as was represented, and why my plugs had awful rusty-red deposits all over them...and why I STILL had to keep the timing retarded way too much...then I found, through a little internet research, that when they claim to raise the octane by 4-7, they are actually talking about TENTHS of a point...i.e. raising the octane from 92.0 to 92.4 ot 92.7...a pretty minuscule amount for the money...

woaface

02-19-2004, 09:57 AM

My dad always forgets to use 91-93...so I never let him fill the tank.:shake:

BillyGman

02-19-2004, 10:12 AM

RV, I didn't know about what the actual octane increase was, so I find that an interesting point that you've made. As far as the red deposits on the sparkplugs though, I've seen that on the plugs of my 73' Corvette and I don't use octane booster in that. I remember reading somewhere about a claim that the red color is can also be caused by additives that are used in some brands of gasoline.

I've also read claims that some octane boosters use lead to boost the octane, and that lead can also cause the discoloration of the sparkplug electrodes, and that it's harmless to the operation of the plugs.

GarageMahal

02-19-2004, 10:26 AM

I know 87 is below the recommended rating but that's all my wife uses in hers. Over 20k miles and no problems, but it's stock and isn't driven hard. Mine is heavily modded and gets a lot of spirited use so I always run 93.Hmmm, I would think using below the required octane regularly could lead to warranty issues. It seems to me its worth the extra few bucks for the peace of mind (not to mention the performance gain)

jta

cyclone03

02-19-2004, 10:26 AM

Don't worry about it.
Just drive it easy and enjoy the mileage increase.

The BEST milage I've ever got in my MM was with 86octane on a trip to CA.
(24.85) running 75-80mph!

I even run 89 in mine now when I know I have no reason to run WFO!
(My CPU has been reflashed with the performance tune).

As a matter of fact before the reflash I stop using 93 and always ran 89.
I have tracked my mileage from day one and stock,it gets better milage with 89. One to one and one half MPG better.

RF Overlord

02-19-2004, 10:29 AM

I remember reading somewhere about a claim that the red color is can also be caused by additives that are used in some brands of gasoline.

I've also read claims that some octane boosters use lead to boost the octane, and that lead can also cause the discoloration of the sparkplug electrodes, and that it's harmless to the operation of the plugs.

About the red discolouration, you're correct; however, my problem was much more than just discolouration...I was getting big, fluffy deposits encrusting the plugs to the point that I wondered how they fired at all. When I stopped using the octane boost, they significantly diminished (the remainder was from the lead-substitute I need to run for the exhaust valve seats).

Not sure about octane boosters using lead as that would definitely poison the cats, so any octane booster sold OTC for street use shouldn't have it...

RF Overlord

02-19-2004, 10:37 AM

The BEST milage I've ever got in my MM was with 86octane on a trip to CA.
(24.85) running 75-80mph!

As a matter of fact before the reflash I stop using 93 and always ran 89.
I have tracked my mileage from day one and stock,it gets better milage with 89. One to one and one half MPG better.

I believe it...

Lower octane fuel has more BTU energy, and burns faster, so it WILL produce an MPG increase, and perhaps a little more power, which is offset by the fact that the PCM will be getting ping messages from the knock sensor and will retard the timing, so you aren't getting the FULL performance benefit from your motor that 91-92 octane fuel will deliver.

BillyGman

02-19-2004, 10:44 AM

[QUOTE=RF Overlord]

Not sure about octane boosters using lead as that would definitely poison the cats, so any octane booster sold OTC for street use shouldn't have it.../QUOTE]

The octane boosters I've seen advertise that have lead as a means to boost octane were in performance catalogs, and were intended for oder cars only w/out cats.

Ross

02-19-2004, 12:59 PM

Heavy, it could have been a lot worse. You could have pulled up to the diesel pump by mistake. :down:

CRUZTAKER

02-19-2004, 02:12 PM

I did the same when I first bought mine. Don't feel bad, cause I also posted here, and man did it get out of hand!
Do all the oldbies remember my one of my very first threads...'Octane and Oil'????
That thread got locked down we got so out of hand:rock:
It's nice to look back every now and again:bs::D

jkarp

02-19-2004, 04:07 PM

Ross,

Funny you should mention that. My older brother filled up his van several years ago and got right on I-95. His van wouldn't run worth a darn, he tried everything to get it to un right. In his infinite wisdom he decided that the timing chain had jumped a tooth, so he got a new timing chain and changed it(302 Ford) in a hotel parking lot. Well turns out it wsn't the timing chain but the diesel fuel he had filled the van up with.

Jimmy

jgc61sr2002

02-19-2004, 04:08 PM

Heavy - Not to worry. I could happen to anyone. As stated above drive conservativly and fill the tank with 93 when it reaches 1/2.

BillyGman

02-19-2004, 06:13 PM

jKarp, that's quite a story!!!!!

dflynn5

02-19-2004, 07:40 PM

I know 87 is below the recommended rating but that's all my wife uses in hers. Over 20k miles and no problems, but it's stock and isn't driven hard. Mine is heavily modded and gets a lot of spirited use so I always run 93.

FordNut. This is not good. You have a high compression engine designed for 91+ One tank will not hurt at all but using 87 all the time and you may burn a hole in your pistons. Seen it happen and it is not pretty.

FordNut

02-19-2004, 09:38 PM

FordNut. This is not good. You have a high compression engine designed for 91+ One tank will not hurt at all but using 87 all the time and you may burn a hole in your pistons. Seen it happen and it is not pretty.

I guess we'll find out. She won't buy premium. The LS we traded in on it was the same, required 91 and she always ran 87. It had over 30k with no problems, and this one has over 20k so far.

lgetz

02-19-2004, 10:00 PM

Heavy, it could have been a lot worse. You could have pulled up to the diesel pump by mistake. :down::stupid: Don't ever fill up with diesel it will really screw up your engine.:mad2:

jfclancy

02-20-2004, 08:09 AM

:stupid: Don't ever fill up with diesel it will really screw up your engine.:mad2:
Had a Volvo diesel put gas in it once mucho Black smoke it ran, The Marauder will run fine on 87 as an emergenancy or close to payday thing.
I have on several occasions and will continue to do so it is MY Marauder
after ALL. Do NOT worry about it.You will get optimum performane using the specifed fuel as long as it does not ping consistantly the computer will correct for it and once you use it up run a tank full of the GOOD stuff. No worries.

Joe Clancy :beer: :beer: Hey it is FRIDAY!!!!

MENINBLK

04-18-2005, 10:38 PM

I believe it...

Lower octane fuel has more BTU energy, and burns faster, so it WILL produce an MPG increase, and perhaps a little more power, which is offset by the fact that the PCM will be getting ping messages from the knock sensor and will retard the timing, so you aren't getting the FULL performance benefit from your motor that 91-92 octane fuel will deliver.

RF...

Octane is NOT a measurement of the BTUs in fuel.
Octane is a measurement of the SPEED OF COMBUSTION...
The higher the octane the SLOWER the fuel burns...
Any octane, no matter what it is, still produces the same
exact amount of BTUs no matter how you burn it...

That is why high compression engines need a HIGHER OCTANE fuel.
The higher Octanes help to fight pre-ignition.
The lower Octane fuels are very volatile and burn very quickly.
Lower Octance fuel is good for just about any vehicle not requiring
high octane fuel, and will also aid in making very cold starts easier
during the winter months.

Bradley G

04-19-2005, 04:14 AM

Man these guy's let you off easy!

I made a terrible mistake posting I tried mid grade 89 once(just to see),And I still haven't fully recovered:rolleyes: J/K
Bradley G

RF...

Octane is NOT a measurement of the BTUs in fuel.
Octane is a measurement of the SPEED OF COMBUSTION...
The higher the octane the SLOWER the fuel burns...
Any octane, no matter what it is, still produces the same
exact amount of BTUs no matter how you burn it...

That is why high compression engines need a HIGHER OCTANE fuel.
The higher Octanes help to fight pre-ignition.
The lower Octane fuels are very volatile and burn very quickly.
Lower Octance fuel is good for just about any vehicle not requiring
high octane fuel, and will also aid in making very cold starts easier
during the winter months.

RF Overlord

04-19-2005, 05:50 AM

Octane is NOT a measurement of the BTUs in fuel.

I never said octane was a measurement of BTU...I said that lower octane fuels had more BTUs available...but I've done more research since I made that statement, and I now know that it's wrong.

I was originally under the impression that lower-octane fuel was less highly refined than higher-octane fuel, and that led to my "more BTU" statement...just as diesel fuel has more BTUs available, in part due to its lower level of refining. However, both regular and premium grades of gasoline are apparently refined in the same fashion, but premium gets a different additive package to improve its octane rating.