87 octane only in 2001 sporttrac 4.0?

[prerunsprttrac]

I was told by the salesman at the Ford dealer to only put in 87 octane in my 2001 sporttrac that i bought.

My question is....why, and will anything other than 87 harm my truck like he said it would? Also has anyone else ever heard of this?

F.Y.I.
4.0, auto, 2wd

 

[jimbo74]

check the book... most of our trucks run just fine on 87, they were designed for it and the engines are so advanced that they dont need the anti knock properties of higher octane

 

[X24]

Your timing is set to run on 87 octane. The SOHC has a knock sensor that will automatically slow the timing if it does knock. Not good for performance, but good for the engine. Get a chip if you want to run higher octane.

 

[jimbo74]

putting in higher octane that it wasnt designed for will allow the fuel not to burn as efficiently thus hindering its power with varnish deposits from unburned fuel

 

[mosinman]

octane

The weird part of all this is that it seems the salesman actually knew what he was talking about! Strange goings on!

 

[A Quiet Boom]

Higher octane only increases power if the engine is optimized for it. Higher compression and advance timing require higher octane and will increase power but if your engine is set up to run 87 and does so without detonation you can actually lose power by running higher octane because it burns slower causing peak cylinder pressure to be lower. Either way it's not a major difference, I run premium octane fuel through engines periodically to help clean the fuel system but I'm talking about premium top quality gas instead of the generic junk I normally run. For example my nissan has 10:1 which requires 93 octane, if I run generic gas in it it runs poorly compared to when I run name brand gasoline but my old F100 has a 8:1 bigblock and runs happily on whatever I put in the tank so from time to time I'll run a tankful of "good" gas to clean out the crap that the generic gas doesn't. Just run regular gas and you'll be fine.

 

[Bwana Bob]

My '92 won't run on 87 octane at all. It pings like crazy. In the summer when its hot and in the winter when they force us to buy that awful reformulated (oxygenated) gas, it won't even run on 89 octane. So, for a good part of the year I have to run on 91 octane. The only mods I have are a cat-back exhaust and a K&N air filter.

What's the fix to make it run on lower octane fuel? The newer explorers seem to run fine on 87 octane. I tried cleaning the MAF sensor, and squirted cleaner into the throttle body (downstream of the MAF), but to no avail. What am I missing?


Thanks.

 

[X24]

I think what happens is the rings and seals go bad and that causes you to lose compression in the cylinders. When detonation starts, it can actually start chipping away at your cylinders and cause them to get like bowl shaped, thus reducing the compression even more. The only way to fix your problem is to do a rebuild. I think thats what happens.

 

[91Exploda]

No acutually there is a fix for the OHV pinging. Sometime a vacum hose on the intake manifold falls off. Go to the drives side of the manifold. There are some hoses kinda on the top/rear of the manifold in the back. See if all of them are on. Then there is a "Spout" connector on the passenger fender. Kinda beind the air box. Pull it out and you have just retarded your timeing a full 3 degrees and the pinging should go away. Don't throw it away, put it like in the glove box>

 

[aldive]

Your truck will run just fine on 87, after all, its what it was designed for.

Using high octain fuel will in no way harm your motor; its simply wasting money.

 

[John_Rock]

I've been running 87 octane fuel in my ST for 2.5 years.
I have over 55K miles with no major problems.
I've stayed away from getting an aftermarket computer chip just for the fact that you will always have to run the high octane gas.

One of the first most beneficial mods that I did was replace the stock airbox with a KKM filter. No more wheezing when you hit the throttle.
I'm very happy with the way my truck performs.
Someday after I get a custom rear bumper I will probably get a catback system.
And I could also increase my performance by changing my diff gears to 4.56 or 4.88's.

 

[A Quiet Boom]

Originally posted by Bwana Bob
My '92 won't run on 87 octane at all. It pings like crazy. In the summer when its hot and in the winter when they force us to buy that awful reformulated (oxygenated) gas, it won't even run on 89 octane. So, for a good part of the year I have to run on 91 octane. The only mods I have are a cat-back exhaust and a K&N air filter.

What's the fix to make it run on lower octane fuel? The newer explorers seem to run fine on 87 octane. I tried cleaning the MAF sensor, and squirted cleaner into the throttle body (downstream of the MAF), but to no avail. What am I missing?


Thanks.

Typically detontation in older engines is caused by carbon deposits in the combustion chamber, they create hotspots ans pre-ignite the fuel/air before the plug fires. The simple cure is to run gas treatment formulate to remove these deposits but the correct cure would be to remove the heads and clean the carbon from them and the pistons. Oil-burning only makes this worse since the oil leaves carbon deposits as well.

 

[MONMIX]

It's true , it's true , it's true.
When I first got my Ex , out of habbit I kept puttin' in 92
When I finally got to puttin' in 87 like I should the truck actually ran better !!
No lie !! It ran better with 87 than with 92.
That is fine with me. When you are talkin' a differance of 10 to 12 cents per gallon.

 

[Bwana Bob]

AS I recall, my truck never ran on 87 octane without pinging. Now its 10 years old with 150k miles and it isn't always happy with 89 octane. It will ping under a relatively light load, like going up a gentle slope. Interestingly, the ping
occurrs over certain rpm ranges. I suspect carbon in the combustion chambers, but I've tried a couple of fuel additives to no avail. Is there an additive that really works?

If the knock detector is supposed to automatically retard the timing, why does my truck still knock? Is there a way to test the knock detector circuit?
I could at least check the connectors, of course.

Thanks.

Bwana Bob

 

[rpenner54]

I have owned my explorer for 4 years now and have run nothing but 85 octane from day one.

 

[Jason_25]

Bob, try Seafoam. It will clean out the combustion chamber of carbon deposits. You may also want to try and re-tighten your lower intake manifold bolts as well.