I posted on the v-6 board concerning my f150 xlt pinging and knocking on 87 octane. The dealer replaced the MAF sensor yesterday and told me to fill it with 87 octane. It still runs terrible. I live in central florida, east of Tampa. Any fuel brand better than the rest in this region. Someone replied and suggested I ask you this question. I have been using shell and racetrac stations.

 

Hi Grendel444,

Steer clear of Racetrack gas, as it's known to be of relatively poor quality, though there are a lot of people who use it due to it being cheap. It's just not a good quality fuel, and I would never put it in the tank of any vehicle, unless you were literally going to run out of gas.

I would suggest trying Texaco, Amoco, and Citgo, in that order, as they tend to have higher energy contents in more places across the country than not.

Shell has been a bit spotty depending on hte geographic region; here in Virginia, it's been an excellent fuel in our direct experience, while out West, in California and other areas, it's nowhere near as good or consistent in it's energy content according to the feedback we get. Most places in the East Shell seems to be OK from the feedback we get, but I honestly don't have any good data on Shell in Florida, so your local Shell may be great or it may not.

I would simply suggest using those brands I mentioned first, in the order that I listed them.

You should not be getting any detonation using 87 octane with the factory program, of course. The factory program is so very conservative that it can be run on fuels as low as 85 octane. However, there is octane, which is only a measurment of it's resistance to spark knock, and then there is the actual raw energy content, which is every bit as important. Gasoline energy content is expressed in terms of the number of BTU's per lb. or gallon of gas. You may have the octane, but not have enough energy content to support certain conditions in the combustion chamber, so that's why it pays to use the best quality fuels available.

Some brands to steer clear of are Exxon (very low energy content compared to other top name brands), BP (high sulphur content) and any off-brands, or "no-name" fuels like Racetrack, as you never know what you're getting, other than you can be certain it's the absolute cheapest fuel available on the wholesale spot market, which you do not want.

I hope you are under warranty, and if so, keep making the dealer respond to this until you find the cure. One of their last resorts is to remove the octane shorting bar, which pulls out timing and reduces power. Make sure they thoroughly check, inspect & test every other possibility first, such as another bad mass airflow meter/sensor, EGR problems which can easily cause detontaion, carbon buildup in the combustion chambers, etc., before they remove the octane shorting bar, due to the power drop you will experience as a result. Again, as conservative as the factory powertrain programming is, that vehicle should never detonate on 87 octane fuel, though every once in awhile, you'll find one that does, and seems to defy diagnosis.

Good luck, and if & when this gets sorted out, please do post back and let us all know what the culprit seemed to be, if it's identified specifically.

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer

 

THanks for your reply. Your knowledge on the fuel quality is impressive. I was a fuel spec. in the military, but I dealt with jet fuels and I never considered the regional differences, or BTU vs octane in commercial gas. I am not very wealthy and because of gas shooting up to $1.80 or more for premium, I have been using racetrac (when I had a Mazda and toyota I used amoco, but I didn't need as much and the cost was lower)I am under warranty for about 3 more months and I am going back to the dealer and am forcing the issue (I don't want to, but it seems to be the only solution)I will post back if and when they fix this aggravating problem.
Thanks again.

 

Hi Grendel444,

With your experience in fuels, if you have anything you can share with us, we're all ears, too!

Glad to hear you're under warranty, continue to hold the manufacturer responsible then, thru your local dealer. And by all means, please do let us know if & when they determine what the actual cause is. Don't let them get away with "this is normal", and they should not ever have to remove the octane shorting bar, either, unless all fuels in that area are really that poor in quality, and we have yet to ever see that with the factory program.

Best of luck,

------------------
Mike Troyer
Performance Products, Inc.
National Distributor of Superchips
(540) 862-9515
Email: mtroyer@compuserve.com
Performance Products F150Online Superchip ordering system: F150Online Superchip Ordering System
First National F-150 Online Rally Event Organizer