2000 Tahoe 5.3L Bad Ping

[SmokeEater2]

I picked up a 2000 Tahoe 5.3L with 60K miles. Only problem is a heavy ping on acceleration and mild ping at cruising speeds. No ping below 1500 RPM. I orginally thought it was carbon knock since the lady that owned it did not drive it much and I'm sure she did not put her foot in it to keep it clean. I did a tank of Techron. No difference. I did Seafoam into brake booster. No difference. Topped off with 93 Octane (10 gallons). No difference.

I Hooked up a OBDLink SX scanner. No codes. Recorded a short trip and it says timing on #1 cylinder is 45-50* advanced at 1900 RPM. That would surely cause the ping, but any ideas on what would cause the timing to advance that much?

This morning I replaced the MAF with new AC Delco. No difference.

Thoughts and idea's are appreciated.

Thanks!

 

[buzzsaw714]

that ping you hear is common injector noise at 50-70k. it goes away on its own.

 

[SmokeEater2]

that ping you hear is common injector noise at 50-70k. it goes away on its own.

I'll add that to the list of things to check for. I'm still wondering why timing is so advanced. I've read a lot about the knock sensor problems with the early 5.3L's. If the KS is bad, would the ECM run the timing up that high?

Thanks for the input.

 

[buzzsaw714]

I know my 5.3 is tuned and the timing is increased quite a bit... they have a false knock that kicks in at higher rpms in the 2nd and 3rd gears. if your engine knocked you would know it... im not sure though its hard to diagnose over the internet