What gas are you running? I recommend BP or Shell Premium. Sometimes the variable octane thing doesn't like certain brands of gas...or the place you are getting it from is watering it down.

 

What you are experiencing is detonation (Aka: Engine knock, spark knock or pre-ignition) and it is not a desirable condition. Detonation can cause broken spark plug electrodes and rings, abrasion/pitting and overheating of the pistons if allowed to continue.

Now that I scared you, detonation is not necessarily destructive for stock engines. Engines can run under light levels of detonation, even moderate levels for thousands of miles with no detrimental results. However, performance engines, well, that is another story.

Under normal conditions, an engine will burn the fuel/air mixture at a precise time in the cylinder. This timing is controlled by or better yet, in conjunction with several components in today’s modern combustion engines. Cam Phasers, Variable Timing of the PCM, a multitude of engine sensors, and even the brand of gas all play a part.

As Ken recommended, change you brand of go juice and see what happens.

If no change, take it in under warranty.

HTH

 

I see that you're from California, and I'm guessing that you're using some form of reformulated fuel. It can definitely cause detonation, but it theoretically reduces pollution from carbon monoxide. However, one oxygen enhancing additive, MTBE, has been found in water supplies. And MTBE causes cancer.:exclaim: Here are a couple of links for basic information:

http://encyclopedia2.thefreedictionary.com/unleaded+gasoline

http://www.scienceblog.com/community/older/1996/A/199600655.html

The Atlanta area is on a reformulated fuel schedule (starting in September?), and I feel your pain (as former Georgia Governor Zell Miller would say)! At any rate, detonation is supposed to be detected by the knock sensor (s), and timing is supposed to be retarded to compensate. But crappy fuel is crappy fuel...and it also robs horsepower!:exclaim:

 

steve these guys know what their talking about,i do not use anything except bp,shell and chevron dont care about where chevron comes from tho.i had the same problem,the dealer filled it with valero and i fowled sute.the guys on imboc impressed me to use the above no problems,good luck.

 

i think ive been having the same problem, was actualy just gettin on here to post it. i have a brenspeed tune (does it with both the 91 and 93 octane tune). i've been using shell 93 octane gas. it almost sounds like a loose heat shield (which is what i initially thought it was), but now im not so certain. starts at around 4000 rpm under heavy accelleration. the car only has 4000 miles on it. im gonna try returnin the car to stock tune and see if it still does it.

 

MTBE, to the best of my knowledge is not used any longer to blend gas.If I am not mistaken it is blended now with ethanol.We used to transport MTBE in bulk liquid form on our boats.It is one of the harshest chemicals we have ever dealt with after two loads we would have to change the packing in all our valves due to the caustic nature of the MTBE.

 

i think ive been having the same problem, was actualy just gettin on here to post it. i have a brenspeed tune (does it with both the 91 and 93 octane tune). i've been using shell 93 octane gas. it almost sounds like a loose heat shield (which is what i initially thought it was), but now im not so certain. starts at around 4000 rpm under heavy accelleration. the car only has 4000 miles on it. im gonna try returnin the car to stock tune and see if it still does it.

Try the stock tune and see if it still does it.

Contact Brenspeed and tell them what is happening, and that you need an adjustment in the tune from them.

Chief_jo you are running a stock tune? If so bring it up with the dealer. This has nothing to do with your oil.

 

MTBE, to the best of my knowledge is not used any longer to blend gas.If I am not mistaken it is blended now with ethanol.We used to transport MTBE in bulk liquid form on our boats.It is one of the harshest chemicals we have ever dealt with after two loads we would have to change the packing in all our valves due to the caustic nature of the MTBE.

I hope you are right, it's nasty stuff.

The ethanol is corrosive enough on our engines.

 

MTBE, to the best of my knowledge is not used any longer to blend gas.

Rick,

I think that you may be correct on that -- I was thinking about not mentioning MTBE, but did so to help make my point. Also, just in case there are still any fuel additives on the market that contain MTBE. A number of states do mandate reformulated or reoxygenated fuel at various times of the year. I know that I can tell the difference in my Camaro SS, which has a relatively high compression ratio. It definitely pings on occasion, even with 93 Octane fuel -- and two knock sensors!:frown:

 

Mike,You are 100% correct on summer / winter gas .

 

MTBE, to the best of my knowledge is not used any longer to blend gas.If I am not mistaken it is blended now with ethanol.We used to transport MTBE in bulk liquid form on our boats.It is one of the harshest chemicals we have ever dealt with after two loads we would have to change the packing in all our valves due to the caustic nature of the MTBE.

You are correct. It's long gone from the market. And you comments are correct. The company I used to work for had an R&D department that was looking at enhancements to the MTBE process. It came and went real quick.

 

put stock tune back on (what a difference, almost dont want to drive it without the brenspeed tune). same ping, only lasts for about a couple seconds (if that, mayb only one) and only under very heavy acceleration. im going back to the brenspeed tune. spoke to and took for a ride my township mechanic who specializes on fords (for all our police cars etc) who said he wouldnt worry about it, and that it possibly has to do with the reformulated gas that they change a few times a year (like mentioned above)

 

I run the cheap gas from high volume stations. Costco, Towne Pump, Fred Meyer. Sometimes 87, sometimes 91 if I want to play. Never had any pinging or detonation.

Fuel up here has had 10% eth during winter since the 90's due to wood stove smoke settling in the inversion layer, and EPA came in and pressed the issue. Many vehicles would have trouble shortly after the winter switch due to filters plugging from the eth loosening up gunk in the tank. Now the governor has mandated 10% all the time to appease... well you know. :neutral: Although I'm firmly against food for fuel morons (and how that has harmed horse owners with hay prices!), its probably better to stay with 10% rather than switching every 6 months and causing problems.

I'd see my Dealer if it were me.

 

I had the same problem in my 01 bullitt and I use this fuel additive called Torco and this stuff works awesome its not a octane booster but a race fuel concentrate. It transforms a 93 octane into 102 unleaded octane and it will not harm o2 sensors. I use this every time I fill up and you really feel the difference

 

To ease your mind on the ambient temperature it has been in the 100 degree range (98 - 103) here in South Texas for a couple months now and I have no ping at all, the car is driven daily in town and on highway with the A/C on to the tune of 250 to 300 miles a day. I run 93 octane from the local distributor (one company fills all the pumps, except shell blahhh) and run a 93 tune from Brenspeed as well.

 

I had the same problem in my 01 bullitt and I use this fuel additive called Torco and this stuff works awesome its not a octane booster but a race fuel concentrate. It transforms a 93 octane into 102 unleaded octane and it will not harm o2 sensors. I use this every time I fill up and you really feel the difference
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DubsBullitt


can you run the octane booster stuff or in this case Torco with a tune that is specifically written for 93 octane gas?

 

I had the same problem in my 01 bullitt and I use this fuel additive called Torco and this stuff works awesome its not a octane booster but a race fuel concentrate. It transforms a 93 octane into 102 unleaded octane and it will not harm o2 sensors. I use this every time I fill up and you really feel the difference
__________________
DubsBullitt


can you run the octane booster stuff or in this case Torco with a tune that is specifically written for 93 octane gas?

Yes you can. Alot of people use this because of all the crappy gas and this WILL take all the pinging away and it is not a octane booster look it up go to competition race fuels.com the product is called mach series accelerator. make sure to get the unleaded blend.