wildazme

ok, i have been having a problem for a lil while now and i have no idea why. when i gun the car at full throttle my car gets a pinging detonating sounds. i have just installed 4 new o2 sensors in the car to see if it would help but it hasnt. the fuel filter was changed not all that long ago. the current mods i have are in my signature. i get the pinging problem when i have an 87 octane tune on the car, the only time it stops is if i use 93 octane gas with the 87 octane tune. when i put the 91 octane tune on the car it pings even with 93 octane gas. i took the tune off completely and even stock the car pings unless i use 93 octane gas. any ideas?

Chopper

There's something wrong with your engine.It could be carbon build-up in the combustion chambers or a dirty MAF element.The carbon can be cleaned out by spraying a fine mist of water into the intake tube.This water flashes to steam in the combustion chamber when the cylinders fire and blasts off the carbon.It takes a while to get this to work but beats the crap out of pulling the heads to mechanically scrape the carbo off.
A dirty MAF element causes the engint to run lean and can cause detonation that way.Clean this very delicate wire with alcohol or electrical contact cleaner.

Li0nHart

what engine compression are you running?

wildazme

this car is second hand so i only know what i did to it, the engine is stock so its stock compression, i remember the previous owner saying the fuel pump was replaced but dont know with what kind. i cleaned the maf wires and still the same thing, and i ran sea foam in the intake.

thunderjet429

make sure the engine in timed correctly first.

I_AV8_4U

Same prob with my '97.
Thunder... How do you time these engines? Won't it throw a code if the timing is incorrect? I am under the impression that you must time it with computer, not the ole timing light bit. Am I wrong? The dealer tells me that a fuel system flush will cure this. What do you guys think?
BTW, I also replaced the O2s.
Wild...Let me know what you find, as it sounds like we are in the same boat here!
Troy

richinwa

Just had the same issue with my 96 GT that I had just bought from a woman that was completely unmolested and probably never seen over 4000 rpm. I removed the uper intake and soaked the tops of the valves with carb clean and sucked out all of the carbon with a snap-on hand vac (what a bitch to do). then reassembled it, cleaned the injectors with 70 psi injector clean and drove the **** out of it. No more ping at higher rpm's.
However yours goes away with the higher octane were as mine didn't so you may have another issue. Sorry to hear you blew a crap load of money on 02's for nothing. If you have an 02 problem you will know by the check engine light coming on. The EEC V system is very sensitive to air fuel ratio's and miss fires.