rangerheave

i own a 2010 Mustang GT with 8,200 miles on it. Since Ive bought it, I have added JLT CAI, Bama tune, Flowmaster axel back and 3:73 gears.

Ive noticed recently that when the tach gets to just above 4,000 RPM's i hear knocking coming from the engine. Almost like a fast ticking sound.

Assume I am the biggest mechanical moron you have ever spoken with and fill me in on possible reasons why this would occur.

Nuke

You could be running the incorrect octane or your local fuel is suspect or your tune is incorrect or a host of other reasons. Try loading a lower octane tune or tank-up with higher octane fuel and see what happens. Remember: when trying to use a higher octane fuel, you'll need to drive about 10-20 miles before the higher octane from the tank makes it to the engine immediately after filling the tank.

rangerheave

Thanks for the reply. I have been hoping I may have just gotten some bad gas and not something internal to the motor. I filled up this morning with 93 Octane so we'll see how things go over the next couple of days.

Nuke

If it continues to knock with the new fuel, load a lower octane tune. It's not too uncommon for fuel in certain areas to be a bit "off" of their rated octane. It's posible you may just need to pull a degree or 2 of timing with the tuner. Altitude can play a role as well as other things. % ethanol doesn't always help, either.

siggyfreud

I would think ethanol would help due to its higher octane, despite its lower energy?

Nuke

I'm not familiar with how the guys that write the tunes deal with that; the potential to be running straight fuel vs. fuel with "up to 10%" ethanol.

ski

I read that E10 fuel is supposed to have the octane rating specified at the pump.
That said, it involves a mixing process, which can lead to an incorrect blend(intentional or not).

Burns331

I doubt its octane, i would be looking for another issue to cause the tick

MurderedStang

I'm not sure if this is a correct response but I'm in FL and we have a FEW places that sell gas with no ethanol, it's more expensive but maybe you have a place where you live?

Daniel98GT

An exhaust leak can sometimes make a ticking sound at certain rpms.