VQ Engine Ping / Knock

[PHoward]

Hi Guys, Ran a search for this on the forum, but could not find a thread under the Murano. My engine pings at part throttle. It's a 2005 and for the first two years of its life it was fine. For the past two years it's been pinging when I accelerate. What's interesting is that it doesn't ping if I rev it, or if I push it real hard. But if I baby it and accelerate slowly, as soon as the CVT "shifts" down it pings for a brief period. I did a bunch of stuff to stop this ping: I use the best gas I can get (Chevron 94), I SeaFoam'ed it, I used copious amounts of Techron, I took it to the dealer for injector cleaning, etc etc. The darn thing still pings. In fact the dealer told me it's normal for the VQ engine to ping (I think that's a load of crap). So, other than the quality of gas, or carbon build-up, what else can cause ping at partial throttle? The EGR valve perhaps? I'm out of ideas and my dealer is of no use. Your suggestions would be greatly appreciated!

[kll]

pinging is related to ignition timing. mixtures cant detonate at ideal positon in cylinders. it is directly related to knock sensor on engines. also can be indirectly related to revolution sensor and cranck position sensor. i dont know your car very well, but engine is engine. did you check that sensor(s)? (according to my experience in past on a BMW, overheated engines tend to ping easier than healthy engines can it be related to gasket? I was using high octane gasoline to prevent. it was actually working. but i am not sure about reason. may be someone can tell us) and did you check with OBD scanner? about trouble codes?

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as a note
if a dealer or mechanic tells you that any obvious abnormal thing is normal in any car, better to run opposite direction. this is my experience.

[tech22]

If the engine is pinging as you stated there should be a code stored in the ecm.Have someone pull the codes and get back to us.

[PHoward]

So, I bought an OBDII / EOBD scanner. There are no trouble codes, no freeze frame data...

I'm at a loss to what this could be. The ping that I hear does not last for long, only a couple of seconds. It's almost like the knock sensor is too "lazy" and takes its time to adjust for the pinging. It sure irritates the hell out of me, but what concerns me is that eventually this is not a good thing for the engine - right?

Do you guys have any other ideas?

[kll]

do you have a chance to try a higher octane rating gasoline or fuel additive to boost octane?

[PHoward]

I tried 94 octane from Chevron, that's pretty much the highest I can get in Vancouver. Should I try some octane booster in addition to that? I know the VQ engne is extremely high compression, and that high compression is the cause of the pinging. What I don't understand is how do many others run the Murano on regular gas and have no pinging, while I get this pinging even with the best gas I can get. I also read somewhere that perhaps the ignition should be set back about 2 degrees to counter lean fuel mixture, but I'm not sure the ECU can be fooled like that. Plus my MPG would probably become worse, right?

[jokove]

i have the same issue with my 2005 murano,
i hear the ping occasionaly when i accelerate, if i'm going upward it's more probably to come out. i'm using 98 octane TOTAL. no codes stored, my car sound like a tractor for a couple of seconds. THAT IS NOT GOOD FOR A 2005 CAR!!!

[kll]

Originally Posted by PHoward

I tried 94 octane from Chevron, that's pretty much the highest I can get in Vancouver. Should I try some octane booster in addition to that? I know the VQ engne is extremely high compression, and that high compression is the cause of the pinging. What I don't understand is how do many others run the Murano on regular gas and have no pinging, while I get this pinging even with the best gas I can get. I also read somewhere that perhaps the ignition should be set back about 2 degrees to counter lean fuel mixture, but I'm not sure the ECU can be fooled like that. Plus my MPG would probably become worse, right?

a modern car should adjust its timing by itself. if you override it, it will not cure problem, you will be removing symptoms. can it be something,related to exhaust valves? a manufacturing problem? material quality? and do you use correct/new sparkplugs?

[Macsleuth]

hmm, could be carbon in the chamber or on the valves.
Do you regularly use premium fuel? If so, engine should be pretty clean as far as the fuel system is concerned.
WHen was the last time you changed the fuel filter? Have you noticed a decline in fuel consumption?

[kll]

do that car have chain or timing belt?

[Macsleuth]

Just reread the post and noticed the seafoam, so I' assuming the carbon build up in a non-issue. Hmm, Must be a sensor, the engine has a couple from what I remember, maybe one needs to be replaced, although you have no codes. Have you tried running anything for cleaning the Cats?