New G35 coupe owner question...engine knock.

[MkG35]

Hello All, some newb questions here! 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. For the record I also searched the forums here but got threads related to engine mods and such. I'll try modifying my search.

Thanks in advance for any answers.

[Ozz1113]

I dont have a stick but between you and me, I don't think you should be hearing any knocks. I don't know what the procedure is but try to reset the ECU. It should be as easy as unhooking the battery for 10 minutes. That should reset the parameters. I also believe the engine knocks the most during the shift. Does the car feel as if it loses power?Good luck.

[MkG35]

Thanks Ozz1113, I agree that it shouldn't knock at all. I will give it a few more refills with the high octane stuff to see how it does. If I have to I'll make the dealer reset the ecu, just so I can have a paper trail of any issues with my car. It only has 1800 miles on it.

Thanks again.

[J-Owner]

Its a sports car so the engine is more tuned towards higher output and that engine is set for the higher octane fuel.

It has something to do with the combustion burn or something. there are about a million threads on here on the topic so do a search and I am sure you can find your answers.

Only use Premium. It that is a problem then you should have bought a dfifferent car. your engine will thank you. Besides I figured it up and premium only costs about $22 extra a month. Not a big deal.

[MkG35]

J-Owner, not sure your post was directed at me, but if so, read from the beginning. I never stated or inferred I had a problem using high octane fuel. The post is in regards to persistent engine knock, not using high octane fuel.

I also performed a search of the forums, but as I stated, I got hits on people with engine mods and such so I didn't search further.

If you can point me to a post that discusses engine knock on a new engine using high octane fuel, I would be most appreciative.

[redhed]

maybe your knock sensor(s) aren't working properly. i have an '06 automatic coupe and i've never heard one peep out of it. and i've run everything from 87 to 93 octane.

[C-Kwik]

I'm thinking you're not actually hearing engine knock. You'ld more likely hear it under load while in gear and accellerating. I'd venture to guess what you might be hearing is the movements of the dual-mass flywheel. This is normal. Some people seem to hear it more than others. Not sure if there is more of a difference from car to car or driver to driver.

[MkG35]

Red, thanks. I just might have the dealer check it out just to be safe.

[MkG35]

Thanks for the response C-Kwik. That is exactly when I am hearing it...under load when accelerating. Interesting theory though.

[C-Kwik]

Ahh...I read the first paragraph and skimmed the rest so I didn't catch that and thought it was only occurring between shifts.

I'd have a dealer check it out...

[MkG35]

Hey C-Kwik, np. I did take it the dealer to have it checked out. I'll cut-n-paste an (edited) update I made to another forum:

"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 did, it made it worse. 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 (manuf) 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 problem is only slight, but I can hear it at times.

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

[rydwhite]

Sounds like a big load of BS to me too. If the car is still under warranty they should take of it.

[Ozz1113]

Did they

Hey C-Kwik, np. I did take it the dealer to have it checked out. I'll cut-n-paste an (edited) update I made to another forum:

"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 did, it made it worse. 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 (manuf) 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 problem is only slight, but I can hear it at times.

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

Did they look at the spark plugs or check the O2 mixture levels? Fuel injector pressure?

[MkG35]

Hi Oz, no they did not. I took it in today to ask if they could throw in some BG44K additive just in case the tank of crap I had in there left some deposits. They had some other BG substitute that they could have "sold" me. I was a little annoyed that they would not have just given it to me since I was having a problem, and not try to sell it to me.

I got into it a little with the tech stating that I didn't care what Nissan said about some knock being "ok", I wanted it fixed. I asked what he would do if he were in my shoes, and he said, "I'd try another ecu". I said to go ahead and do it, he said I had to make the request myself (he couldn't) through Infiniti Consumer Affairs (or whatever it's called). Don't know if it's bull or not, but I picked up a can of Techron (put out by Chevron) and I'll give that a try. I'll give it little while longer before I go to another dealer (farther away of course), or give Infiniti a call to "authorize" an ecu replacement.

Sheesh, you would think they would give us the red carpet treatment with what we pay for these cars.

[MkG35]

Hey rydwhite, one would think so, but given that dealers go by what the manuf. says, what can one do? (other than staying away from that brand)

I believe that in the interest of doing "good business" the dealers should step up to the plate and do whatever they can to fix the problem regardless. At least make the appearance that you give a hoot about the customer and not hide behind whatever the manuf says. My dealer failed in this area.

I'm certainly not giving up yet. I still love the car even if it isn't quite 100%.

[Ozz1113]

Hi Oz, no they did not. I took it in today to ask if they could throw in some BG44K additive just in case the tank of crap I had in there left some deposits. They had some other BG substitute that they could have "sold" me. I was a little annoyed that they would not have just given it to me since I was having a problem, and not try to sell it to me.

I got into it a little with the tech stating that I didn't care what Nissan said about some knock being "ok", I wanted it fixed. I asked what he would do if he were in my shoes, and he said, "I'd try another ecu". I said to go ahead and do it, he said I had to make the request myself (he couldn't) through Infiniti Consumer Affairs (or whatever it's called). Don't know if it's bull or not, but I picked up a can of Techron (put out by Chevron) and I'll give that a try. I'll give it little while longer before I go to another dealer (farther away of course), or give Infiniti a call to "authorize" an ecu replacement.

Sheesh, you would think they would give us the red carpet treatment with what we pay for these cars.

I'll quote somehting I got in the mail yesterday:"We want to take this oppurtunity to conrgatulate you on the purchase of your new G35. We're confident that you're going to appreciate the undeniably high level of satisfaction that Infiniti offers. It starts with the superb blend of elegance, innovation, and performance.

It goes well beyond that in our approach to service. Welcome to the Infiniti Inner Circle"