Modern Ethanol Fuel in FJ40

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Dec 14, 2014
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My newly purchased 1971 FJ40 is the oldest vehicle I've owned; I don't know too much about older engines. I was surprised to find little information about ethanol fuel with the F and 2F engines. My FJ40 has the original F engine, and I've been wondering how the modern fuel with ethanol affects the engine.
 
There seem to be some hundreds of them represented here running just fine on it. E15 in CA, I think. I ran E85 for a smog check once, just a gallon and just for about an hour during the test. I filled it with E15 right afterwards. I'm not sure it helped, but I did pass that time. I guess I should try it again.
 
From most of the stuff I've read on the ethanol fuels-they act like a cleaner, they will clean all sorts of junk from the fuel-holding parts, then deposit them in the small orifices of the system(carb)-ending up as gunk, plugging seemingly everything. Additionally, they seem to aggravate the rubber/cork/Viton/Buna-N/, etc seals, causing them to fail prematurely.
I was able to revive an old Ryobi blower using Seafoam--don't know if this would help with the truck. I try to run non-ethanol fuel whenever I can get it in the cruiser-so far about every 3rd tankfull-I haven't had any issues yet.
 
There seem to be some hundreds of them represented here running just fine on it. E15 in CA, I think. I ran E85 for a smog check once, just a gallon and just for about an hour during the test. I filled it with E15 right afterwards. I'm not sure it helped, but I did pass that time. I guess I should try it again.

You are correct... Exhaust gasses are a function of what is being burned. The biggest trick in emissions tests are burning alcohol. I was stuck once and did just that ... Bingo... Passed.. I do not believe it works with extreme poor engines, but it does with engines that are missing numbers by a small amount. In auto parts stores they sell a product in a container, "Pass emissions , guaranteed" , look at the ingredients .. Yes, main one --alcohol.. There ya go.
 
As mentioned above, it's chemically harsh on many of the rubber & leather parts. It also draws moisture, leading to rust & corrosion.

There is a driveability difference with RFG because of the higher vapor pressure / lower BP. This translates to fuel boils out of carb bowl overnight, leading to hard starts next day. Fuel boils out of carb bowl sitting in traffic, leading to rough,stumbly hot idle. Fuel is easier to vapor lock in the pump, making it hard to reprime the system if tank level is low.
 
My 1976 owners manual specifies 90 octane but that is for leaded gas. Most unleaded ethanol here in middle America is 89 octane while regular unleaded is 87. That being said I get about 5% better fuel economy with regular unleaded fuel in my FJ 80 so I am going to move up to premium 91 octane in my 40 at the next fill up and see what that does for performance and economy.
 
My understanding has been that ethanol is a concern mostly for smaller engines, which have trouble burning it fully. However, I'm good friends with an older gentleman who owns corvettes and only uses fuel with no ethanol, and a corvette engine could hardly be considered small. Of course, we've all heard/learned from experience that ethanol will eat away hoses not made for it. I'm guessing by now that 100% of the hoses in my 71 have been replaced. That's pretty impressive to have them all be original.
 
If you have the option I would run non-ethanol., or find a gas additive you like.
I have to drive out of my way and pay more per gallon for it. But my 40 might sit more that my other vehicles and I ve read different things about the ethanol mixed fuels breaking down faster and having a shorter life. I feel like my 40 runs better on non-ethanol but havent been able to drive it enough to say for certain. I have read before what a poster above put that the fuel can burn off in the carb and lead to other things like mentioned
I also run non-ethanol 89 in my 07 fj cruiser as I feel it runs better and gets better mileage, I can notice a 20 mile difference in tank range with different gas for that one.
In my high mile daily driver I use whatever Im in the mode for but its most always the cheapest as it will be gone quick and I dont care about that one

this helped me find a couple different stations where I travel. Seem to be growing or at least the list is.
http://pure-gas.org/
 
I feel like my 40 runs better on non-ethanol but havent been able to drive it enough to say for certain. ...
I also run non-ethanol 89 in my 07 fj cruiser as I feel it runs better and gets better mileage, I can notice a 20 mile difference in tank range with different gas for that one.

Not your imagination; gasoline has more energy density than ethanol, so you do get more power and hence better fuel economy.
 
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