Modern ECU's are quite smart: a lot of computational power is in all of them. There are a few different systems in place to detect knock and any events should be logged and stored so that you have a trail when pulling info off of the ECU.

If the techs pull this info and find little to know knock events in the counters, or if clear them and run the car (could attach to OBD and see any events in real time), this would likely show that no pre-ignition events are occurring. That's a good thing.

Knock can be pretty hard to hear at RPM: lots and lots of noise going on. This is why you must rely on sensor output to see how things are going under the proverbial hood.

I spent a lot of time looking at log outputs with my old car and its very primitive aftermarket ECU, and knock curves stood out like a sore thumb. I ran a winter map to compensate (thank you crappy blends on the east coast). I should not complain I suppose since West Coast gets cat piss for fuel. Their 91 octane...ick. AZ/CA/CO all those states are fuel challenged for high performance. :D

- b

No more pinging
 

No more pinging. To make a long story short, the nissan dealer changed the oil and also did an update to my ECU. Don't know what the update to the car computer was but it does run better and I hardly ever hear the ping anymore. Right now it's hotter than hell in Vegas and the car runs nice even on the hottest day. Also, I've searched all over town and every gas station here only has 91 octane.

One Update, I was having oil temp problems. I had a Stillen 19 row street oil cooler installed by the Nissan dealer. The car runs like a completely different car. Full power all the time. Doesn't go into limp mode anymore. The exhaust note sounds great when fully hot but not in limp mode. I recommend every 350-370 owner get at least the 19 row street oil cooler. It won't void your warranty if the dealer installs it and your engine will love you for it. No need for the 24 row racing model if you're not racing. :driving:

100 octane fuel
 

I finally figured out that some Rebel gas stations (not all of them) in Las Vegas DO sell 100 octane race fuel. As of 10/01/14 the price is 7.99 a gallon :eek: but it's worth it. The car runs really nice... I MEAN REALLY NICE!. I've been using straight 100 octane for about a month and I love it. :driving:

From my experience i got the same problem. I used shell 91 octane and my z started to ping in very low rpm usually while taking speed bumps in second gear close to 700-600 rpms and a loud ping went starting the car in the morning. I change to Puma 93 octane the only gasoline available with 93 octane and the ping was gone. No ping in speed bumps or cold start ups. I thing the z is tune for 93. I prefer shell better than puma here in Puerto Rico but shells doesn't have 93 oct.

I've added klotz fuel accelerator and it actually works bringing up the octane and removing ping or detonation,I've found fuels where i am claim certain octane numbers but they don't hold up,in the states best stuff would be torco fuel accelerator

I was wondering why only some have engine ping issues. Our cars should run fine with the 91 octane fuel and also the knock sensors should have prevented any engine pings unless retarding the timing doesn't help.

Sorry forgot to mention my car is supercharged,iam only running 7lbs of boost and still ping/Knock ocasionaly,my cars tuned by seb at specialty z with ecutek,just started using renegade 98 octane unleaded,amazing difference,also the klotz and other accelerators were helping also before I got the 98

An easy way to increase octane is to add E85 if available. Try a little test this way. When the tank is almost empty add about 2.5 gal of 91 octane E10 and 1.0 gal of E85. That would give a mix of about 30% ethanol. The octane would be raised a point or two. The fuel trims in the ecu should have enough room to compensate for the extra ethanol. If that doesn't work you can fill the tank with your normal fuel and be back to where you were. If it does help, this would be an inexpensive fix. E85 is $1.50/gal her in Texas. :)

After owning my 370 for a few weeks, I noticed that it would ping (spark knock) slightly when going up hills.

In the manual, 9-5, it states that "Now and then you may notice light spark knock for a short time while accelerating OR driving up hills. This is no cause for concern, because you get the greatest fuel benefit when there is light spark knock for a short time under heavy engine load."

Hope this helps anyone who had the same concerns as I did. I guess it's normal. This car is truly a different animal.