Filled it with 89. Ran it 100+ mi. Even at night when cool. Still pinging. Second and third gear shifts. But not if I baby the clutch. Never on WOT or under load. Only when shifting. Any other ideas before I go to the dealer? thanks
Check for a loose intake housing clamp that may be causing a vacuum leak/lean condition from unmetered air entering post-MAF. I know you said it's stone-stock with no mods and it's pretty new, but you never know. It's worth checking. Then, I'd take it to the dealer. My 01 GT (no knock sensors) pinged since day one, but 92-93 octane cured the problem. You might have a bad knock sensor, vacuum leak, bad MAF, etc ,etc.
Good idea. I will check the post MAF to intake. In the meantime, I have been to the dealer. Coincidently it was an extremely humid day, right before a storm. Rode with the mechanic and the car did not ping. Couldnt even make it ping. But in talking with him, there was reluctance to do anything without a check engine light on. Claimed that everything is preset at the factory and can't be changed per EPA regulations. Does this sound reasonable? He did offer to hook up a "flight recorder" that I would activate when I detect a ping. Said it would detect things like the MAF, 02 or knock sensor, etc if they were flaky and not yet 'throwing a full code'. Waiting 4 weeks for dealer to call me with the 'recorder availability. Granted the ping might not affect the driveability of the car but, it takes away from the driving experience and I don't like it. Does the fact that it does not ping when the engine is cool and running rich, or when it is very humid outside give any hints? Thanks again
It sounds like your dealer is actually being very cool. It's awesome that they are willing to hook up a "flight recorder" of sorts to log data on your car. I'd definitely take them up on that if your pingissue persists. Regarding your last question - all other things equal, heat is often a contributing factor for pinging. That and engine load. Easiest way you can get ping is usually on a hot, humid summer day, A/C on, lugging in 5th gear up a hill at part throttle. Stab the throttle under that same scenario and you'll here pinging that's as loud as a bell on an old-school bicycle! At least on the mod motors it sounds like this. So, it's possible that with production variances you might just need to run higher octane when you are flogging your car and perhaps during the hot weather months. Check the post-MAF intake to throttle body just to be sure and if it persists, definitely take your dealer's offer of the data recorder. I can totally relate to being aggravated with the pinging. Drove me nuts! Can't say I even totaly resolved it - I either run 92-03 octane or run the SCT mail-order tune with some fuel and timing tweaks to manage around the ping. Not ideal, but my car ran a best ET and MPH immediately after the tune with worse 60's than pre-tune. And similar DA/weather.
