I’ve been getting pinging at part throttle at freeway speeds when under load. From 3,500 rpm to roughly 5,000 rpm in 3rd gear and higher. Doesn’t happen at wide open throttle, only when applying light throttle on freeway inclines. Been wracking my brain trying to figure out what it could be. Tried Lucas injector cleaner then Lucas Octane booster. No change. From what I read, knock sensors rarely fail. I have the service records since the care was new and it has been meticulously maintained. Has had new plugs 20k miles ago (currently about to cross 80k), has had Mahle fuel filters replaced twice, the most recent also at 20k miles ago. Going through my folder of receipts, the only thing that hasn’t been done is the fuel pump. I found this thread and even though this is an 09 DFI motor, the symptoms are identical. http://www.6speedonline.com/forums/9...gine-ping.html

It’s going to my Indy this week. The car pulls like a freight train, no other issues being exhibited. What do you guys think??

Well, something isn’t able to properly adjust timing or fuel flow at a certain the throttle position. What about any codes? What about airflow sensor?

No codes. New MAF. Even swapped my old MAF which is still good back in with no change. I’ve noticed an increase in the level of the pinging over the last few weeks which is leading me to think the fuel pump may be on its way out.

Is there a high pressure fuel pump on your car? If not, I’d suspect that the fuel pump is fine if it pulls strong at WOT without pinging? Or does it ping at any throttle position?

No pinging (at least no audible pinging) at WOT, just part throttle.

Thanks. That’s what is leading me to think it’s the fuel pump. Knock sensors should pull back the timing if needed and these rarely fail. Tried Lucas Octane booster. No change. Tried Lucas fuel system cleaner to remove any buildup. No change. Engine temp is normal. So that leaves A/F ratio too lean. If the pump is not supplying enough fuel it’s gonna run lean and I’d imagine it’s too much for even the knock sensors/ecu to dial out. Then reading that other poster on 6 Speed having the exact same symptoms and it ended up being the fuel pump.

Could bad O2 sensors cause a lean condition?

Without throwing a CEL? Not sure.

A fuel pump needs to deliver much more fuel at WOT than at part throttle. So if WOT is fine, I cannot see how it could be the fuel pump.

Correct, but seems the pump wasn’t delivering enough fuel at part throttle in the 6 Speed Online I linked above, even though it was supplying enough at WOT. His symptoms mirror mine exactly. Also, if it was due to increased compression due to carbon buildup wouldn’t it ping at WOT, not just part?

But his fuel pump issue was the 2nd pump - the high pressure fuel pump - whereas your car, and I’m not 100% sure about this - only has a lower pressure fuel pump and a completely different fuel delivery setup via DFI.

Regardless, though, I could see a problem manifest itself whereby the fuel pump delivers different levels of pressure that depend on fuel flow. Like having more than one speed. So at WOT, the pump would be on high, but at part throttle, medium or low. That’s what I would find out next.