Engine Ping on 91 Octane
 

Hey guys, Ive been a long time lurker on this forum ever since I picked up my Z back in January. I decided I should probably go ahead and register as I have just started experiencing my first potential issue with the car. My apologies in advance for the long explanation below but I will try to explain the problem the best I can.

Recently I have noticed a slight engine ping while accelerating. The ping generally occurs under very light load (think typical city driving) between 1500-3000 rpm and tends to get more prevalent as the engine temperature rises. I have always run premium gas in the car (91 is the best you can get here in Phoenix) typically from Chevron or Shell so I'm not sure what to make of it. I took the car into the dealership last week hoping that the noise was just a loose heat shield. After inspecting the car the service manager took it for a drive and also diagnosed the noise as a slight engine ping. Confused, he instructed me to try running an octane booster as a troubleshooting step and report back to him. I have since tried this and noticed that the ping is nearly all but gone. Reverting back to regular 91 causes the ping to return.

My only thought is that this could be caused by either 1) crappy AZ gas or 2) a lean condition caused by bad O2 sensors. Before I take the car back to the dealer I was wondering if anyone else has experienced any sort of the same behavior? If not, any idea on what could be the cause? The car is completely stock.

Btw thanks for having me. :tiphat:

Try a "different gasoline station"! Choose either one(Shell or Chevron). Preferably run it down to almost empty, before refilling at a different station. Also, do not mix brands of gasoline-combustion levels and additives are not all the same.


Welcome to a very good site!

Thanks, its good to be here. :tup:

Concerning a different gas station, unfortunately I have already tried it with no luck. I have tried Chevron, Shell, and even a Quik Trip with no change. I ran each down to about an 1/8 tank before refilling. I have been sticking with shell for the last two tanks to flush everything out. No change :confused:

Dang! It's beyond my knowledge. Hopefully one of the more experienced mod members will chime in!

I never use any cheap gas my motorcycle does ping with cheap gas such as from a wawa or a off name station. I usually go to Sunoco Or Shell

I haven't experienced that at all - but then again, I'm still on my first tank of gas. :( One would suspect a bad O2 sensor would cause all sorts of other problems like hard starting and idle problems. Did they see if the ECU was throwing any codes?

Hopefully some expert will chime in.

No codes as of yet. The car also runs great otherwise.

The sound is really only noticeable with the windows down and no radio on which is why I think it is only a "slight" ping. Is it possible that Nissan finds a small amount of ping acceptable? Unfortunately I'm not very experienced when it comes to newer engines. My last car was a carburated 87' Nissan Sentra.

Ping, or "ticking"?

http://www.the370z.com/engine-drivet...mal-sound.html

Its definitely not a ticking sound. The sound is metallic and sounds as if a heat shield is rattling under the car under light acceleration. Its most noticeable when accelerating in first and second gear. It might be present in other gears as well although road noise tends to drown it out past second. I had the car inspected at the dealer when I took it in and neither me or the mechanic could find anything loose underneath the car that would make the noise. :confused:

I'm really surprised the ECU lets any detonation occur - at least that's audible. I figured it would just back off the timing.

"Cheap gas" will not be any different from "name brand"gas except for the munufacterer's additives, which are such a small percentage of the fuel as to make no difference at all in combustion. The raw distillate all comes from the same place, refinery. The only thing that will cause a ping id the octane level. A 91 octane from a Sunoco, an Exxon, or a Global is still a 91 octane.

You should hear a loud ping when either running at very low RPM under load try running in 5th gear at a low RPM and giving it some gas. Or run it up a hill, again in 5th gear at low rpm, you should also hear a loud ping.

If the engine really is pinging, take it to another dealer for a check. Wow, it sucks not being able to get 93 octane where you live! Yet this engine should run normally on 91 octane, says so in the manual.

Sounds like a heat shield noise...if it only happens at a certain rpm, that is where the resonance occurs that makes the shield rattle. A ping is very noticeable, almost sounds like a small hammer banging against a large piece of metal. If it is a rather thin metallic noise, it is almost certainly just a rattle of a metal heat shield.

Find a gas station that doesn't put ethanol in their gas. See if that makes a difference.

I agree with Steve, on the probable cause, the octane your putting is within spec of nissan's requirements, I would suspect a bad o2 sensor is keeping it to lean, the Dealer has to dig into it and find your problem, his suggestion of Oh well just add some additive, and will see what happens is BullShit, a new car shouldn't be pinging, that's just Embarrassing, If he won't do nothing about it find another dealer like it's been suggested. :tiphat:

I too have noticed this ping at low rpms, in 1st gear mostly, even more so in reverse, I always run 91 octane
I can get 94 octane here in Canada at 1 gas station(Sunoco), maybe ill try that to see if it makes a difference