07 XL, stock. 1600 miles.

Runs great, except sometimes it pings, slightly, under load, in OD. The RPMs at that point are 1500 or so. (I wish I had lower overall gearing, but new gears cost so much.)

I know the engine has an anti-knock sensor. I know the computer will retard the timing to compensate. Basically, I know this doesn't hurt the engine.

As an experiment today I put 1/2 a tank of 93 octane in with my existing tank of 87 octane. Boy did that cost a lot!

The truck now runs like a clock. It is noticibly better. In fact, it feels like a totally different truck.

Has this been an issue for you all? I'm (of course) worried about the additional cost of the 93 octane and I'm also worried about excess carbon buildup. If I lived in a totally flat area this wouldn't be an issue, but all of my driving is local and hilly. I've tried locking the OD out but it hurts my mileage a lot and it is hard to remember.

My wife's 05 Escape runs very happily, under all circumstances, on 87 octane. We run BP gas in both vehicles.

My theory is the additional octane prevents pinging. The computer is then able to run the timing at the factory value instead of the retarded value. (Is there a way to see what timing the engine is set at?)

There is a real long hill down the street from me, that is a 40mph hill and very steep. On 87, the truck begins in OD, starts pinging kinda bad, clumsily shifts to 3rd, and then, when I crest the hill and the RPM's go up, pings slightly until OD kicks back in.

On 93 the truck pulls the hill in OD the whole way, without pinging. And remember, this is a long, steep hill.

I'm at 300' above sea level if that matters.

I'd take it to a dealer, but I know:

1) They will mess something up or damage the bodywork (They alway do.)
2) Tell me this is normal (It is, I suppose.)
3) Treat me like I am retarded.
4) Make me wait all day.

So dealer intervention is not an option. This truck will never see a dealer. None of my vehicles do.

Thanks for listening. Comments are greatly appreciated.

 

The only way to reset the timing is to get a custom tune for the computer.
I know that's not cheep but will save you from having to run the 93 octane to make it run good.And it will run better all around.

 

I've been doing some reading. (Scary!)

Would a cooler plug solve this? I could drop down one heat setting. It would be the same thing as retarding (permanently) the timing a bit.

I looked into the engine bay of my truck tonight. I'm pretty competent mechanically. However, those plugs are pretty far back there. How easy are they to change?

Finally, some of the plug wires are resting on the valve covers. Is this okay?

(I just love working on stuff. I haven't done any serious mods yet but I have done some very simple ones, just to get a feel for the vehicle. So far: Sylvania XtraVision headlights, Interstate MTP-65 battery, Bosch Icon wipers, Super crazy Draw-Tite receiver hitch & a HitchSafe.)

 

Okay, changed plugs today.

I expected it to be a bit easier than it was. The #1 plug gave me a real hard time. Thankfully I noticed the holes in the wheel well for #2 and #3. It ended up taking me 4 hours. Next time I bet I can do it in 2. My wife has an I4 in her Escape and changing plugs takes like 20 minutes. I still prefer the F150, though!

I spent a long time yesterday learning about spark plug heat ranges. It was very difficult to try to find a plug that was colder than what was in the truck, because I didn't know what was in there and because when you go through the automated plug finder pages they all say different things. And, for example, different model years take different plugs. No site listed 07 plugs so I went with the 06 listing. The most common part numbers I got were Motorcraft SP506 and Motorcraft AWSF-32C.

So I pull the plugs. I read somewhere that the left and right bank had different plugs, but mine were all the same, Motorcraft AGSF-34N. I think that is the same plug as a Motorcraft SP506, but I don't know for sure. The owner's manual does not list a spark plug! At the bottom of this post I have linked a chart that I found that lists Motorcraft to NGK conversions. The AGSF-34N isn't listed, but all the AGSF-34 plugs translate to a TR5 class NGK. NGK gets colder as the number increases so I bought TR6 plugs. A TR7 is actually a BR7EFS, so I can do that if I need to go even colder. I'll pull a plug every once in a while and check how it looks and go from there. (All this kind of reminds me of tuning two stroke motocross bikes!)

The only (minor) oddity was the factory plug gaps were not uniform. I expected a little less variance since they must have millions of these things made by a machine.

1) .050
2) .049
3) .051
4) .055
5) .048
6) .050

I've attached a picture of how the pulled plugs look. They have 1770 miles on them. They are 1 to 6 from left to right.

So I popped in the TR6 plugs. I used a little anti-sieze on the bottom half of the threads, making sure to not get anti-sieze on the business end. I couldn't get my torque wrench in there so I just did 1/16th of a turn more than finger tight. All the plugs were manually gapped to .054 which seems huge to me.

And the result? Not earth shattering, but slightly better:

1) A slightly smoother idle.
2) The exhaust note has a deeper "burble" sound. (Seriously! I have no idea why, but even my wife noticed it and she doesn't notice anything.)
3) Off idle transitions are much smoother.

Everything else is the same. I have a full tank of 90 octane right now, and the slight pinging happened with 87 octane so nothing will show up until it gets diluted back down to 87. I usually gas up at 15 gallons (I hate letting the tank run dry) so my next tank will be 88.5 octane and the one after that will be 87.75 or so. (Assuming this is how gas and octane work.)

So we'll see if the colder plug transfers more of the combustion chamber heat to the heads and cures the preignition issue. One article I read gave a safe range of 500°C-850°C, with 500°C being the point where the plug isn't hot enough to burn itself clean. They mentioned that going down one heat range can drop temps 70°C to 100°C.

I'm sure the truck is just fine as is, because the pinging happens so infrequently, but I don't like the idea of having it retard the timing so much that it "runs out" of available timing to work with. I'd prefer (unlike everyone else in the world) less power if it means smoother and more reliable operation. Hopefully these plugs will cool things off enough to not have to retard the timing to the point it is maxxed out.

Or, I could just be plain wrong about everything. It wouldn't be the first time.

At least it gave me an excuse to work on the truck!



Motorcraft -> NGK chart: http://www.clubplug.net/moto_ngk.html

 

You will find that the higher octane fuel will give you slightly higher fuel mileage, which helps to offset the extra 20 cents a gallon (at least where I live)

The reason for this is that the computer does not retard the timing as much, hence the increase in mileage as well as power. Slight increases though.

Run a few tanks of super, mid and regular and see the difference yourself.

Note also this trick will not work on all engines, but only those that are pinging on regular and have to have the timing set back to stop it (timing set back either manualy or by the computer)

David

 

I'm hoping the cooler spark plugs work. So far so good. I don't drive enough to change tanks of fuel regularly so it will be a week or two before I can test lower octane fuel.

I plan to pull a plug after 500 miles or so to look at its condition. I'm willing to go one step colder if needed before I resign myself to using high octane fuel permanently. Plugs, in the long run, are much more economical than more expensive fuel.

I'm not real good with math, but if I calculated it right, I would have to go from 17MPG to 18.3MPG to break even running high octane versus regular octane, assuming that there is a 20 cent difference between grades.

( 5.20 / 5.00 ) * 17 = 17.7
( 4.20 / 4.00 ) * 17 = 17.9
( 3.20 / 3.00 ) * 17 = 18.3
( 2.20 / 2.00 ) * 17 = 18.7
( 1.20 / 1.00 ) * 17 = 20.4

The good news (?) is that the higher the price of gas goes, the less mileage increase it takes to break even.

 

Please post with results as they become available, I am always intersted in finding out these things work out. So many times you only hear initially, and not all of the details.

I have been looking into a 07 F150 with this engine - so i am curious!

David

 

My mileage spreadsheet to date:

http://www.raleighgyros.com/pdf/Mile...aintenance.pdf

 

My new 07 has almost 2800 miles on it now.I've noticed it pings very slightly upon heavy acceleration or climing a hill.I only use 87 octane gas from Shell or BP.Highway driving at 60-70 mph,a/c on,i'm getting 18.7 mpg.Around town i'm getting 14.5-15.5 mpg.
I took it to the Ford dealer this past weekend for its first oil change,and they didn't even scratch it!

 

Minor update:

Updated mileage spreadsheet: http://www.teamprimerib.com/pdf/F150%20Mileage.pdf

I ran some (overly complex) calculations. Up until the spark plug change I ran 87 octane exclusively. The half tank of 93 octane bumped the tank to 90.48 octane. Today's half tank of 87 octane dropped the tank to 89.12 octane.

So far no pinging.

So, worst case scenario, I can run 89 octane and be fine. Of course, I hope the cooler plugs will allow me to run 87 octane. We won't know until I dilute the tank more. I put so few miles on the truck that it takes forever to burn even half a tank.

A weird new change, probably unrelated to all this stuff I am doing, is that the truck is more willing now to down shift on grades, but it does so very smoothly. Before, it would hold the gear way too long and (finally) abruptly shift down. I don't know if the computer is learning my driving habits or what. I've removed the negative battery cable as recently as last week so this isn't 2000 miles of learning. Whatever the cause, it is nice, and radically different than the previous behavior.

One interesting thing I noticed at the gas station was that 87 octane was $3.05, 89 octane was $3.17 and 93 octane was $3.29. Usually there is a 20¢ difference between grades but today it was 12¢ more for 89 octane and 12¢ more on top of that for 93 octane.

I'll post an update in a few weeks. We have a relatively long trip planned within the next two weeks so that will give me a chance to really test things.



I hope the level of detail I am going into here isn't boring you all. I'm posting this in the hopes that it helps someone, and also so I can keep track of things myself.

 

Good info. Thanks for posting.

I have done a few very unscientific tests and really can't notice any difference between fuel grades.

I do notice I get better gas mileage in the summer than I do in the winter. I guess it's the summer blend fuels.

I even get better running the AC as compared to winter with no AC (but windows up, so that part is consistent).

Thnaks again.

 

More quasi-scientific mumbo-jumbo to follow. You have been warned.

I've been driving a bit, and diluting the higher octane gas closer to 87.

I took a long 400 mile trip this weekend to the beach. The octane in the tank, at that point, was 87.33. I know it probably isn't that accurate in real life, but work with me here.

I pulled a plug before we left and it looked perfect.

The truck did not ping. I got 21.4MPG!

Granted, the trip was 55-65MPH, with brief sections of 70-75MPH. We had some stop and go driving but not a lot. I didn't specifically go out to get good mileage. Our load was me, my wife, my son and my tool box.

For fun, I did the tripmeter trick and watched how close the cruise control kept the speed in check. It mostly was +- 0.1MPH but on hills it would drop back a MPH or two. I was impressed because my wife's Escape has cruise control and it freaks out over even the slightest incline.

The truck needs further testing locally. We have several hills that are prime targets for light pinging. I'll try to hit them this week.

Linked you will find my updated mileage table. There is a new column that took me forever to program. It is the octane in the tank after the fill up. It is, of course, dependent on the previous tank's octane and how much of the new octane gas is added. I used a nominal 27 gallons for the total tank capacity, which is the rated capacity of the tank but we all know that is probably not the exact size.

http://www.teamprimerib.com/pdf/F150%20Mileage.pdf

Anyways, I'm pretty optimistic at this point, and the great mileage on the trip was a nice bonus.

BTW, check out my new mirrors:

https://www.ford-trucks.com/forums/6...r-options.html

I'll post more in a week or two.