bosco500

When my car is at idle, if you pop the hood and listen VERY closely there is a pinging noise coming from directly behind the manifold. It is not very loud, but is noticable if you get pretty close to it. It pings about 1 time every second, so its not very fast. It almost sounds like a clock ticking slowly. Anyone know what this might be?

Craig Mack

What octane gas do you use ? (Regular, Silver, Premium)

bosco500

93 octane.. would that make it ping?

Craig Mack

93 ? Hmmm, My mom had an old volvo once, and she used regular when it required higher. It started pinging after a while. My sister's 95 Max (obviously requiring premium) pings or used to b/c she puts in the cheap regular (86 octane).

I use 93 octane as well, sometimes using 89 when I am short on cash. My engine sounds fine. And never pings.

Craig Mack

Engines are more likely to detonate under full load, low engine rpms, and hot weather. This is because the vast majority of the torque is produced from 1800-3000 rpm.

Are you always using 93 octane ?

What heat range plug is installed currenty?

What is the timing set at?

These are usually the three main culprits for detonation (low octane, not cold enough plug, advanced timing).

bosco500

I have always used 93 octane, the plugs I am using are
NGK PFR5G-11. Should I use PFR6G-11? Isnt that a colder
plug?
About the timing.. is it even adjustable on the max? If so
its never been adjusted.

Daniel B. Martin

Pinging, also called engine knock, has a sound often described as an unpleasant irregular metallic rattle, similar to shaking a coffee can full of marbles. Pinging is pronounced when the engine is under load, such as climbing a hill or rapid acceleration. The sound you describe is not pinging.

There are other vehicle sounds which are similar to pinging. The most common example is an exhaust system heat shield. This can cause all sorts of different sounds. Heat shields also emit strange sounds as they cool, after the engine has been turned off.

bosco500

well, it happens when the engine is hot. It cant be heard while
driving, its very quiet unless you are close to it. Sounds like its
inside the back of the manifold.

asianpr3082

i get this noise too i hear it in the engine room and hear it but not too loud but i also use 93 oct and i wait for the car to warm up and it still does this i think we are having the same prob it sounds like it's one of the rockers cuz it sounds like the sound under the hood sound as fast as the rockers dont know doh....

MAXTOUT

Is it maybe more of a click or ticking?

asianpr3082

i hear a ticking noise

Daniel B. Martin

The sound is not coming from the rockers. 4Gen Maxima engines don't have rockers.

NUGE

I have asked about this same problem on this forum. I have spoken to NGK and they do not recommend changing the heat range of the plugs. They did suggest to pull out the old plugs and check to see what color they are and if they are all the same color. The dealership refused to change the timig to help with the pinging. I hear it only when the car is shifting gears between 200 0 & 4500 RPM. Or when the a/c is on and the engine is under load. I do not get any king of a ecu code telling me that the knock sensor is bad.I can not think of anything else.

bosco500

well i DO get a knock sensor code from the ecu. would this have anything to do with the pinging?

Eric L.

Knock and Ping are the same thing. Yes, definitely, if your knock sensor is malfunctioning, your engine may ping. This is a problem best diagnosed by the Nissan Dealer.

Daniel B. Martin

AFAIK the dealership cannot change the ignition timing. It is controlled by the Engine Control Module.

bosco500

Daniel -
Do you "think" that if my knock sensor is malfunctioning, and I replace it, it would help solve my problem?

Daniel B. Martin

Causes of pinging include:
- fuel AKI too low
- ignition timing too far advanced
- lean mixture
- carbon deposits in combustion chambers
- EGR valve stuck closed
- EGR passages obstructed with soot
- EGR vacuum signal hose(s) split, broken, or disconnected
- engine running too hot

There are other vehicle sounds which are similar to pinging. The most common example is an exhaust system heat shield which has become loose and rattles or buzzes, especially at certain engine RPMs.

Daniel B. Martin

Yes and no...

If you run on 91 AKI fuel your engine should never ping. If it is pinging, there is some underlying cause which should be identified and repaired. Replacing a bad KS may just mask the symptom. This would result in less pinging but the retarded ignition timing would diminish engine power and fuel efficiency.