87 vs 89 octaine

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What do you put in? it seems that when I use 87, my fj60 will diesel when I turn it off,,,, when I use 89, that problem goes away. Is it just a venting problem? or do i keep paying 10 cents more a gallon to prevent that from happening?




Nicholas
 

FJ40Jim

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A stock 2F should be able to run on mexican ditchwater. No need for anything more than 86 octane.

Something is allowing your engine to run on. Wrong/fouled plugs, carbon buildup, rich carb, defective ICS, idle adjustment....
 

stinkyfj60

 
 
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I run my 60 on 85 and refuse to go any higher. These things were built for third world countries and you probably wouldnt notice the difference if you did run it on higher octane.

When me and my wife first got together I worked at a gold mine here in the Valley that was going through reclaimation. I just worked security keeping crews coming in and out to the equipment.
Anyway, part of our pay was so much gas per week out of the tanks there on the mine. I was using my '72 FJ40 with a rebuilt F engine and Weber carb. One day my boss asks me if I am having problems with the gas cause his 1990 Chevy truck wouldnt run on it. All the guys on our crew were complaining about that cheap ass yucky gas that would even dirty up your fuel filters. My 40 never knew the difference.
 

stinkyfj60

 
 
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NocalFJ60 said:
Fix the problem.. Your cruiser should purr with 87. Next month you might be putting 91 as it gets worse.
What would cause this though? I thought octane readings were just anti-knock and the higher the compression the higher the octane reading needed to keep getting pinging.
I agree though, he needs to fix the problem... whatever that might be and do a basic tune up on it.
 

GLTHFJ60

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I believe that the higher octanes have a higher flash point which means that it takes more compression and heat to ignite it before the spark. That means less detonation and ping I do believe. Correct me if I'm wrong.

If you're having problems, get some seafoam and run it through your system. It will help out alot.

:beer:
 
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stinkyfj60 said:
What would cause this though? I thought octane readings were just anti-knock and the higher the compression the higher the octane reading needed to keep getting pinging.
I agree though, he needs to fix the problem... whatever that might be and do a basic tune up on it.

I have no clue. He didn't say it was knocking while driving. I thought it kinda shutters when he turns it off.If the engine is stock with orginal compression ratio you should not have to run higher octance. I heard the High Performance engine at MAF require a higher octane.

What shape is your carb in? I would try and make sure it is adjusted correctly.

Follow Jim C advise up the page first and see if that helps.
 

billmc

 
 
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Here's a guess. Your fuel cut solenoid is not doing it's job and is allowing fuel after shutoff. Using higher octane is just preventing dieseling of that fuel, which is instead rinsing the oil off your cylinder walls and running down into your sump. Go back to 85 and fix the real problem.

Bill
 
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Dose this also apply to the 3FE also because my truck runs like s... when I run the cheep stuff in it. I thought I read somewhere that 89 is recomended for the 3FE.
 

billmc

 
 
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Fast Eddie said:
Dose this also apply to the 3FE also because my truck runs like s... when I run the cheep stuff in it. I thought I read somewhere that 89 is recomended for the 3FE.
The Owner's Manual for the FJ62 calls for 87 or higher octane (I believe it's a little higher compression than the 2F). Some, including me, have had trouble running anything under 91 without a lot of pinging. I've solved that problem by adjusting the AFM, and am now running 89 octane withot problem. Haven't tried 87 yet.

Bill
 
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My 86 FJ60 w/336+k miles runs fine on the 85 octane regular we have here. Also runs well on Pemex Magna grade which, as I recall, is 86 octane. Figured I've saved nearly $3000 over 19 years by using regular.
 

GLTHFJ60

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Where do you guys live where you're getting 85 and 86 octane? In the northeast, we only have 87, 89 and 91

:beer:
 

Mike S

 
 
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Mudrak tells me to run the higher octane, as his experience is that cruisers run an higher octane fuel have fewer problems. But I always run 87 anyway, sometimes lower octane when travelling where it is available. No troubles - the 2F runs fine.

Mike
 
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Here on the Front Range, our Regular is 85, Mid-Grade 87, and Premium 89. I don't know the specifics, but the lower octane has to do with the blend of gasolines used here which supposedly reduce emissions. It seems to have helped as we no longer have nearly the problem with the infamous "brown cloud" prevalent in Denver in the '80s and early '90s. The 86 octane I referred to is regular-grade Pemex, the national oil company (and only gasoline retailer) in Mexico.
 
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use the cheapest but keep good maintenance as to air cleaner, fuel filter, oil, etc. and you will have a very long lasting engine. You can also use chevron with techron; helps.

miami; 87 is the lowest.
 

Phrog

 
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octane

Octanes are lower in Colorado largely because of the higher altitudes...
preignition (knock) is caused when fuels ignite due to high temperatures
resulting from increases in pressure. That's why high-compression
engines (not the 2F) require higher octane fuels. In Colorado, the
starting pressure is lower due to the higher altitude, so the ending
pressure (at top dead center ) is lower as well.

Or so I'm told. My 3F-E is quite happy with 85 octane.

Clear as mud!
 

DBS311

 
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The myth that higher octane will make your vehicle run better is bogus when it comes to our Cruisers. The octane rating refers to the resistance of the fuel to burn. In high compression/high boost applications, you want the slower burning fuel to reduce the chance of preignition (knock/ping). In our low compression motors, we don't want a slow burn. We should make more power (theoretically) running 87 vs. 89 or higher.
 

Mark W

 
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FJ40Jim said:
A stock 2F should be able to run on mexican ditchwater. No need for anything more than 86 octane.

Something is allowing your engine to run on. Wrong/fouled plugs, carbon buildup, rich carb, defective ICS, idle adjustment....

Hmmm... I've heard that before somewhere. ;)

Ditto what Jim says. You can't even buy gas here in the US that is low enough in quality or octane to cause problems for a stock Cruiser. Maybe in Outer Bumfukistan on a holiday weekend you might run into problems.

Buy the cheapest gas you can find and be happy.


Mark...
 
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