Hello All, some newb questions here! I also hope I am posting this in the right place.

I just purchased an 06 G35 6MT coupe a few weeks ago. Straight from the dealer's lot, the engine would knock(ping?) in between shifts. I attributed this to possible low octane fuel the dealer put in the car?? Just speculation however, I babied the car until the fuel was used up and started putting in the higher octane stuff. The knocking/pinging eventually subsided (almost completely)...almost.

This brings me to my questions: I thought modern engines (via the ecu) can adjust to lower octane fuels to prevent this from occuring. if so, why did my engine knock? I did mention this to the dealer and got the, "we only use high octane fuel...dunno". I was somewhat annoyed they might have chosen to use cheap fuel, I expected better.

Another question is, under heavy acceleration starting from a stop, then working my way through the gears, I can just make out some knocking at the beginning of each shift, but it quickly goes away. I don't detect it at highway speeds. Is this in anyway normal? Does the ecu adjust for the higher octane? For the record, I have been trying different gas stations just to see if it helps, but I can still hear it. I've been driving sticks for many years so I don't think it's my driving style.

Again, sorry for possibly naive questions, but it's been buggin me.

Thanks in advance for any answers.

 

Welcome, MG35Coupe, and congrats on the new Coupe.
Most likely the dealer had lowgrade gas in the tank . Keep it topped up with premium and the ping will go away.
As far as the ECU detuning (lowering the timing)......there is a limit to how far it will go. Keep the octane high on refills and the ping should disappear. There is much more cleaner in premium fuel than regular which may have contributed to a carbon buildup in the combustion chambers.
This will take some time, so don't expect it to go away overnight....

If it doesn't disappear, then get the dealer to check the engine's timing.

C.

 

Thanks for the quick reply MSM!

I thought I read a post (can't remember from which site) where someone stated the ecu compensates for a lower grade of fuel, but doesn't compensate when you go back to using a higher grade. Do you have any idea if this is true? If so, would this require an ecu reset?

Anyway, thanks again and I'll keep an eye (ear!) on it.

MG

 

I am having the same issue right now with my 2006 G35 6 Speed. I have always put 93 octane. I have 4800 miles. It just started knocking about 500 miles ago. Since then I have tried 3 different gas stations and 93 fuel. Still does it.

I am not sure what to do next. It doesn'r seem to do it all the time, mostly when the revs are low and I accelerate.

Would this be timing? I need to get it to the dealer and have it looked at. Any suggestions if they say the usual " I don't hear it"?

 

06NYG35, I don't know if this helps or hurts, but on page 9-4 of the owner's manual, it states the following:

"However,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."

Is it possible that they "squeezed" every bit of performance out of these engines by an aggressive timing profile, thus some engines have a tendencies to knock, albeit briefly? I will defer to more knowledgable minds here on whether that may be the case.

I will say that I do not like to hear my engine knock for ANY reason. To me that equates to a problem. Readers here may disagree.

For now, I'm in the same boat you're in. By the way, my car only has 1800 miles on it. Good luck.

 

MG35,

I just read that on another post. Not what I wanted to read. I had a 2003 350Z before the G and that didn't ping once. The G does it too much for my liking. It wasn't doing it but now it seems to more often.

I think I will still have the dealer look so it is a documented complaint in the system.

I may try some octane boost on the next tank of gas and see what that does.

 

06NYG35, as you stated, I would also take it to the dealer to have it checked out. I would not recommend you put any additives into it. The maual states this clearly - you don't want to risk any warranty support later.

Please post an update whatever find out from the dealer. I am still going to perform a few tests, such as today, with the engine cold (it was also raining) the engine didn't ping at all. Hmm, this clue might help the service dept if I decide to bring it in as well.

Again, good luck and please keep us apprised.

 

I have the exact same problem with my 06 6MT coupe, 1600 miles. Had it from the first trip home from the dealer. I keep trying different brands of 93, some better some worse, but in hot, humid weather I can always get a little spark knock under load below 3K rpm. As for the manual reference, that's pretty rediculous given the 17 mpg I'm getting. I'm going to try an ECU reset to see if that helps.

 

Ncroush, just an fyi, yesterday, I pulled the battery terminal to perform an ecu reset (some people let it sit overnight unplugged). I just stepped on the brake and turned the headlights on to make sure the system was fully discharged. I am assuming that a reset occurred because when I reconnected the battery, the car had to adjust the outside temp from 90 degrees down to 72 degrees. Not sure if that is a good indicator or not.

I agree, I do not accept what the manual states either - an engine should not knock at all. Maybe it has to do with this particular engine running at high compression (10.5:1)??

Also, I also don't detect it as much (if at all) when the engine is cold...will have to test this further though.

It's still too early to say whether the reset worked, will have to see on the way home tonight from work.

 

Great, I hope that works for you. I am doing better with a new tank of shell 93 octane. Preignition (aka detonation) is always going to be worse in hot/humid conditions. You probably wont have any issues in the winter. Keep us posted.

 

Hi All, just an update on my G35 knock issue. I took it to the dealer today to have them check it out, they retarded my timing to see if that would have any effect..it didn't. I went back minutes later and got the tech to go along for a ride to confirm that what I am hearing is indeed engine knock. It didn't take him long to confirm it.

He told me he would call the manufacturer to get some input on whether they have been seeing these issues with other dealers and what to do about my issue. They essentially blamed the gas stations for screwing with their mixtures and outside of that, a little knock is ok by them, and there is nothing that can be done about it. The tech didn't buy that at all (neither do I) and he is giving me a copy of the report he made to Nissan/Infiniti.

The problem is only slight, but I can hear it at times (not all times). If retarding the timing had no effect then I might try an octane additive (against my own advice to someone else). The tech said it would be alright to use it just this once as a test to see if it was the particular fuel I was using.

The tech even went so far as to blame the ecu as a possible culprit by not advancing the timing under acceleration when it needed to. He stopped short of saying he could replace it just to see if it fixed the problem. The manuf. would have a problem with the dealer just replacing parts as a test for a solution.

I hope the octane boost sheds some light, if it doesn't, what's left to do? Did I receive a lemon?

As an interesting note, one of the other Infiniti techs owns a Pathfinder that knocks as well and he is also having problems fixing the problem. When he found out what my tech was told by the manuf, he just said, b.s!"