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Infiniti G35 -- Engine pinging

Beginning about 2 months ago (not entirely sure but recently), I started hearing engine pinging in my G35. I started by getting my fuel system cleaned out, maybe not an astute measure to diagnose the problem, but that did not help.

I then figured it was because the octane in the fuel was too low, so I bought the top-shelf octane booster and added it, but that did not help.

Where should I go next? The mechanic? Is there any other step I can take before taking it in? …Michael

Start by checking the fault codes. Make a list and post it here.

NOTE: if your car requires high octane and you haven’t been using it, it’s going to take a few tankfuls to get any improvement. Hopefully you won’t burn a hole in your piston before it purges.

By the what what year is the car?
How many miles?
Are you the original owner?
If not, how long have you owned it?

Common causes of pinging, besides what you’ve already mentioned

  • Ignition timing overly advanced
  • Spark plug gaps are too wide (they widen with miles driven)
  • EGR system malfunction (which would usually result in a diagnostic code)
  • Major mechanical fault with the engine.

the same mountainbike,
Yes, it is recommended to use 93, and I have used 91 (as I know of no station that sells 93 in this locale). I have had the car for 1-1/2 years. It has 83000 miles on it, and I have put about 10000 of those miles on it since I bought it. The pinging began maybe 500 miles ago, at most.

And I don’t know how to get the fault codes.

Why would the timing change, other than some sort of faulty sensor? I am not a mechanic, so I don’t know. How easy would it be to check the gap? I suppose just using a gap tool, like I used decades ago when I installed my own plugs? ?

What is an EGR system malfunction? And if it were a major mechanical fault with the engine, what might this be? …but on the other hand, it does seem to be getting worse, not better. But on the other hand, as well, that could easily be the pessimist in me.

I just read up on the EGR, and it said, “if the EGR system is leaking or inoperative, it can cause driveability problems, including detonation (knocking or pinging when accelerating or under load), a rough idle, stalling, hard starting, elevated NOx emissions and even elevated hydrocarbon (HC) emissions in the exhaust.”

Well, the pinging was my original subject. I have noticed a rough idle. I have also noticed that when I first start the car and let it warm up, as I always do for at least 20 seconds, if I have the windows down the exhaust really stinks. A smell kind of like varnish. Considering the above quote on EGR, does that trigger anyone’s mind?

Is the chech engine light on? A auto parts store can check codes, but nothing will show up if the light is off.

You sure you arent confusing Pinging with a Faulty Timing chain tensioner or guides? Seen this occur pretty regularly.

Your engine is one of the last ones in which I would expect to hear “proper Pre-detonation” It has several safeguards in place to prevent it…and or stop it. In fact I personally have never heard any VQ series engine Ping Proper… This isn’t to say its impossible by any means, but…like I said…doesnt seem a common issue.

Other causes is an out of time engine…which also kind of blends in with the T chain Tensioner and or chain stretch…

Hard to say from here


Even if the light is off there may be stored codes that can be downloaded.

An EGR fault is a possibility. The EGR system basically consists of a tube from the exhaust system to the induction system that’s opened with a solenoid-operated valve to allow a bit of exhaust gas to be drawn into the induction system and mix with the air to keep cylinder temperatures from getting too high. The exhaust gas, which does not contribute to the combustion process, displaces a bit of the incoming air, the oxygen of which does contribute to combustion… and thus cylinder temps. These paths;/valves/orifices can and sometimes do become carboned up and fail to operate properly. The valve can fail to close completely and/or the orifice where the exhaust enters the induction stream can get clogged.

But there are other possibilities too, such as worn sparkplugs or even carbon deposition, since the proper fuel isn’t available.

No disrespect meant, but my impression is that you’ll need to have a shop do the work anyway. Your best bet would be to take it to a trusted mechanic and let them diagnose and repair it. Don’t procrastinate any longer, because sustained pinging can cause serious engine damage.

Thanks, guys. I will take it to the mechanic I trust, and see what he finds. Sounds like it’s not a problem to ignore any longer.

In most cases pinging is caused by an EGR system fault followed to a lesser degree by knock sensor issues.
Pinging is more noticeable on a warmed up engine when it’s under load; as in hard acceleration or climbing hills.

If this is an EGR system fault it needs to be repaired. A little pinging here and there is not too bad. Severe and chronic may lead to engine damage.

OP writes: Why would the timing change, other than some sort of faulty sensor?

Like you say, most likely reason would be a faulty sensor. If your car’s engine uses a knock sensor, that would be the first suspect. Next, a faulty crank position sensor. A faulty ignition system component could cause it too.

OP writes: How easy would it be to check the gap? I suppose just using a gap tool, like I used decades ago when I installed my own plugs? ?

Yes, it is done with a spark plug gap tool. It’s a simple task for a mechanic to check one spark plug. The only way to know for certain if a widened spark gap is causing your particular problem is to check all the spark plugs, and at that point you might as well replace them all with new ones. That’s more expensive of course.

OP writes: What is an EGR system malfunction?

The EGR system kicks in during heavy acceleration or high engine load (like going uphill) to keep the inside parts of the engine cool, done in part to prevent pinging. The specific way this function is implemented depends on the make/model/year, but there’s often an EGR valve involved, and those especially can malfunction by sticking closed, which prevents the desired cooling effect.

OP writes: And if it were a major mechanical fault with the engine, what might this be? .

Carbon deposits forming inside the combustion chamber can cause pinging. Lean operation due to valve or injector problems is another possibility.

George’s comment raises an interesting point. Many of the new cars with variable valve timing use the exhaust valve timing to accomplish the function that the EGR systems used to.

What year IS your car, anyway?