Help with pinging problem

I have a 99 T/A with basic mods (flowmaster, K&N cold air, mild tune - egr/air off, fan speeds, a little touch here and there).

Now that the cool weather has arrived I have a horrible ping under heavy throttle. Sounds pretty bad. I first suspected that I had a bad tank of fuel so I waited out on the tank and re-filled with good premium and it is still pinging. The car has been well maintained. Recent plugs (NGK TR55), injection cleaning, fuel filter.

Fuel pressure at the rail is 52psi with ignition on and 62psi running. Any ideas?

Try cleaning the mass air sensor. Pickup some CRC maf cleaner at Pep Boys or just use electrical contact cleaner.

I often wonder if some engine knock is associated with one or more injectors that are not operating correctly.

Any other ideas....cool weather, fans come on at 180, good fuel, tune-ed up

I see you have the EGR turned off mechanically--The EGR table in the computer ADDS timing throughout the entire RPM range--If you don't delete the added timing in the EGR table--it will ping horribly because the EGR is not functional--You will need to have a tuner "0" out the entire EGR timing table-
You may have other isuues--but i would start there---

a datalog would be really helpful. tblu92 is right though, if they didn't pull timing for the EGR that could be the source of some of your ping. Back in the ls1edit days there wasn't an egr table and when I pulled my egr I had all kinds of knock. I had to go through the high octane table and calculate where my timing was being referenced and pull timing in those cells. PIA compared to what hptuners lets you do now.

I installed a Hypertech tune and that took care of it. The HPtuner at the hands of a professional was able to turn off EGR and zero at the tables.

i'm the one that did his tuning. i'm looking at his high octane table right now.

from 2200-8000 rpms in the .52 - 1.20 g/cyl block, it is all set at 26*

EGR correction table zero'ed out.

now, i did just see something odd. the low octane table is all screwed up. for some reason, it is in the 45* range. guess i need to get back with you one day and reupload another file. don't know how i missed that.

it's making me wonder why it's going into the low octane table.

Im having the same problem, detonation at medium to heavy throttle. My fuel pressure drops 10lbs when I punch it. I did just have heads and cam installed and we tried to tune it with my Vinci tuner but once we saw the fuel drop we figured that was it. Could it be something else?