svt93style

When I open up the car under full throttle I hear this rattling noise, sounds like it coming from under the car.

Any ideas?

Nuke

Are you sure it's not engine ping?

AmericanMuscle4.6GT

i sometimes get the same thing. i doubt its engine ping.....my car is making plenty of power (dynoed 296 rwhp) and my a/f was pretty spot on.........

moosestang

Your air fuel can be spot on and it still ping. Low octane fuel, too much timing, bad gas, really hot engine.

moosestang

Pinging sounds like a piece of tin rattling under the car. If you rev it up and it doesn't rattle, then it's pinging under load. If you are using 87 octane, then switch to 89 or 91.

jahudso2

Yeah like moosestang said it is probably pinging. I would remove 2 degrees of timing in the rpm range it pings in or use better gas.

AmericanMuscle4.6GT

how about revving getting pinging in like the 5000+ range? will this destroy my motor?


i'm on a brenspeed 93 tune and have 93 octane in the car...........should i just go down to the 91 octane tune (i have a non-adjustable xcal1) and still run 93 octane?............pinging, IIRC, is an indication of preignition.......would a lower octane tune (less aggressive timing) solve this? i think i'm just getting bad gas

don't our cars have FOUR knock sensors (on the 4.6)? my car runs strong as ****..........all RPM ranges, it pulls like a son of a bitch.

jahudso2

Are you reving in neutral and still getting the pinging? Ping should only occur under load (while you are in gear) unless your tune is totally off. If you still get the noise when revving in neutral, then you probably have the rattling heat shield problem.

GTItoGT

I get the same thing in the upper rpms, c&l intake, Brenspeed 93 octane, corsa exhaust, had a JLT intake w/ brenspeed tunes first, same deal. I dont know what it is, sounds like an exhaust rattle. I dont know but I doubt its valve ping.

AmericanMuscle4.6GT

i think its the exhaust pipes hitting against my driveshaft loop bolts. they're a bout a millimeter off when i go look under the car..