GT pinging on 87 octain

Florida Bob

New Member
Nov 11, 2004
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Venice, Florida
GT pinging on 87 octane

I'm getting some pinging (knock) under load using 87 octane gas from different premium brands. I switched over to 89 octane and the pinging went away. 1700 miles on the GT. I know that some pinging is normal according to Ford but the 89 octane does seem to solve the problem. Anyone else having this problem?
 
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Florida Bob said:
I'm getting some pinging (knock) under load using 87 octane gas from different premium brands. I switched over to 89 octane and the pinging went away. 1700 miles on the GT. I know that some pinging is normal according to Ford but the 89 octane does seem to solve the problem. Anyone else having this problem?

Did you try a different brand of 87 before going to 89?
 
Florida Bob said:
I'm getting some pinging (knock) under load using 87 octane gas from different premium brands. I switched over to 89 octane and the pinging went away. 1700 miles on the GT. I know that some pinging is normal according to Ford but the 89 octane does seem to solve the problem. Anyone else having this problem?


Some pinging is normal? Who told you that?

Do try another tank but I would also go ahead and take her in anyway. As detuned and neutral as this engine is it really shouldnt ping ever. That coupled with the fact that at least one 3v has had to be replaced due to misfireing. Be safe, take her in.
 
Florida Bob said:
I'm getting some pinging (knock) under load using 87 octane gas from different premium brands. I switched over to 89 octane and the pinging went away. 1700 miles on the GT. I know that some pinging is normal according to Ford but the 89 octane does seem to solve the problem. Anyone else having this problem?



I'm do for my first fillup today and was going to use 87; is everyone else having no problem with 87? When I picked up my car last Saturday the salesman had filled it with premium (93) and didn't even know it would run on 87; I had to tell him! Just curious before I fill up this afternoon.
 
Florida Bob said:
Yes. Exxon and Shell 87 still pinged slightly.

Those are good brands. You can take it to Ford and they'll detune it for you so it will run on 87 :rlaugh:

Sounds like you may have lucked out and got a agressive tune to me, I'd use 89 and forget it. :rolleyes:
 
ttown said:
Those are good brands. You can take it to Ford and they'll detune it for you so it will run on 87 :rlaugh:

Sounds like you may have lucked out and got a agressive tune to me, I'd use 89 and forget it. :rolleyes:

That was my thinking also. If 89 octane stops the pinging, then it must have a more agressive tune. Only some dyno pulls will tell for sure.
 
vld said:
Some pinging is normal? Who told you that?

Do try another tank but I would also go ahead and take her in anyway. As detuned and neutral as this engine is it really shouldnt ping ever. That coupled with the fact that at least one 3v has had to be replaced due to misfireing. Be safe, take her in.

It's in the owners manual. Here's the direct quote from the manual:

Octane recommendations

Your vehicle is designed to use “Regular” unleaded gasoline with pump (R+M)/2 octane rating of 87. We do not recommend the use of gasolines labeled as “Regular” that are sold with octane ratings of 86 or lower in high altitude areas.

Do not be concerned if your engine sometimes knocks lightly. However, if it knocks heavily under most driving conditions while you are using fuel with the recommended octane rating, see your dealer or a qualified service technician to prevent any engine damage.

Fuel quality

If you are experiencing starting, rough idle or hesitation driveability problems, try a different brand of unleaded gasoline. “Premium” unleaded gasoline is not recommended for vehicles designed to use “Regular” unleaded gasoline because it may cause these problems to become more pronounced. If the problems persist, see your dealer or a qualified service technician.

Notice it also says not to use Premium.
 
The 05's have a knock sensor. If you are getting a slight ping on first heavy load, but it goes away in a fraction of a second, that's the knock sensor doing its job. If you get sustained pinging, that would indicate one of two things.

1) very bad gas that is so bad that it is outside the range of adjustment in timing that the knock sensors can handle (unlikely)
or
2) something else horribly wrong. You may be running ultra-lean, have some other computer issue, or have something wrong with the heads like too-high a CR.

Get it into Ford, with a tank of 87, immediately.
 
Try a hard reset of your computer--unhook battery, press brake pedal to drain residual power in system. Rehook battery. Not sure how much "learning" the new system is capable of, but since it has a knock sensor it probably adjusts timing a bit. If the car was running on 93, more than likely timing was advanced as much as possible using the factory settings. Eventually it will learn back down to the 87 octane based on input from the knock sensor, but this could take a tankful or two. The hard reset does it instantly.

Not sure if this will work, but it is worth a try. It works like a charm on other cars that have a "smart" computer (like my finicky WRX). :nice: