TexasHunter05gtNOS

I've got an 05 GT with under 50,000 miles. I do have straight pipes for exhaust, Cold air intake, and a Zex nitrous kit. I have only used the NOS about two or three times.

Now the question: I recently started hearing a sort of pinging noise (almost like that of one of the Jetsons cars) when RPM's are over 4,000. Any Ideas as to what it could be?

Nuke

A few questions:

1. Is the pinging/noise only under load or can you reproduce it at curb side?
2. Are you running a custom tune with that CAI? Octane?
3. Have you tried the next grade octane?
4. Any other mods?

ski

Also, if you're using gas from a Mom & Pop station, then suggest switching to a brand name(Sunoco, etc.) at the next fill up.
And stay out of the loud pedal until the noise stops.

TheYeti

yeah I get the same thing over 4k if I use Circle K gas but if I use Shell, I am fine. AZ gas is notorious for being bad tho...

TexasHunter05gtNOS

I have actually been getting the same 87 octane gas from the same gas station for the last two years. Who knows maybe with the economy they are adding water now (who knows). I have not run a custom tune with the CAI and the noise only appears under load. Ill try another station for the next few tanks and see what happens.

Derf00

I think you may need to retard your timing a degree or two in the upper range.

When I got my tunes from AM/Bama I started using the 91 performance tune. On really warm days I was getting pinging anywhere from 2000 RPM all the way to redline under load. I run only chevron or shell these days (nor more Circle K or valero)

Anyways, I retarded the global spark by 1 degree and was still getting a bit of ping above 4K so I retarded the the 4k to 8 K (?) range by 1 more degree (total of two just for that range).

No more pining under high heat and load. Car drives the same.

You could test your problem with 89 octane gas too. If it goes away then you know for certain you need to retard the timing a bit. Have your tuner do it or do it yourself.

adj86

I live in Dallas Texas and everyone around here uses up to 10% Ethanol in their gas. It doesn't burn as efficiently so that could be part of the problem. I had a knock on the Bama 93 race Tune and it looks like they retarded the timing to fix the knock. The thing screams like a banshee now at WOT no pinging. I'm betting that's the issue, as well as Ethanol in the gasoline. At least thats what I'm attributing my issue to.

ski

If brand name 87 octane does not fix things, then use 89 octane on the next fill up.

If still no good, then fill up with the highest octane in your area.

If that does not completely eliminate the pinging, then it may be caused by carbon that has built up inside the combustion chambers. Dump a can of Seafoam in the tank at the gas station immediately before filling up to dissolve the carbon. (Note: You may have to use a 2nd can of Seafoam on the next fill up if the pinging persists.)