07 G coupe valve chatter...Dealership retarded timing???????

[haloseven]

I have an 07 G coupe which has exhibited a fair bit of valve chatter. This only occurs when it is fairly warm outside. This car has only ever seen 93 octane or higher. The dealership keeps questioning the fuel, despite a shoebox full of high octane (pronounced expensive) fuel reciepts from a number of gas stations. I suggested perhaps something was amiss with the cooling system, since it does this only on warm days.

After a full year of going back and forth with them, they decided to retard the timing. Completely disregarding what I had to say, they dropped it back 3 degrees.

There is now no valve chatter, but there is also a noticable decline in performance, along with noticably different shift points under load!

WHAT HAVE THEY DONE!?!

Can anyone give me any ideas here? I want my power back.

[Sentientbydesign]

I'm not sure what to say regarding your valve chatter, but the retarded timing will adversely affect performance.

It's basically the same thing that the ECM does when you put cheap gas in and the timing retarded to avoid knocking.

[awdjdmtalon]

Just becouse you are using 93 octane doesn't mean you are using quality fuel. If you are getting it at Wal-Mart, Sheetz, local mom and pop gas station, you are not getting quality fuel.

You need to be using fuel from Mobil/Exxon, Shell, Chevron. They don't skimp on the additive, and are less likely to water their fuel down w/ the 10% ethonal that most do.

I have seen first hand the effects of using "Off brand" fuels in a car. 2 weeks ago I spent 5 hours cleaning the intake ports on a VW Passat 2.0T head. The customer said he used 93 but got his gas from where ever it was cheaper. Well let me tell you. The intake ports were at least 30% clogged w/ carbon.

He was having a lot of running issues. MisFires when cold. Knock on accel. After cleaning the intake, the car ran like new.

I suggest you switch to a quality fuel brand, and have the dealer run the BG Intake service on your car. It will clean out the carbon deposits on the intake valves. Those 2 thinks should take care of the knock problem you have. Then have them set the timing back to where it is supposed to be.

[SteveTheTech]

That is an interesting concern. I understand the fuel aspect but if you are getting a knock under normal acceleration using premium and have not altered the engine too much I would think there is something there they are not seeing. I am not going to knock another dealer and without seeing the engine parameters under load.

In the manual there is an exhaust value relearn that I would say take a look at it but in the auto I am stumped.

Can you give me a little more info? When did you first notice this?Do you have any mods?How many miles do you have?Who changes your oil, and with what?Whats the service history, warranty repairs,and history of complaints?

If your car was in front of me I would be able to answer these myself but over the internet its slightly more difficult. I have had to retard timing on a few cars I30s are notorious for knocks but a new G is not usually the issue. I am very interested in this one.

Hang in there well try.

[haloseven]

Hi Steve, I have NO mods whatsoever. I have used fuel from Sunoco, BP, and Exxon with no difference, except when I tried the 100 Octane from Sunoco. Even then chatter was only reduced. Was well over 5$ a gallon at the time. Not a good solution anyway.

WAL MART FUEL?? PLEASE!! to me, giving Wal Mart one dime is worse than a root canal with no anesthesia!!!

I bought the car in November 06, and didn't notice the chatter until around May 07. During this time, the temps here in Pittsburgh average 60F or less. I first brought to the Dealers attention in June 07. It now has 17,500 miles, and has seen only Mobil1 since the day I brought it home. It had 21 miles on it when I first installed Mobil1. The dealership changes it, if I havnt done it myself. I continue to change oil every 3000 miles. The oil is still extremely clean.

Every service interval to date has been met. As for warranty repairs, the only three were: replacement of one o2 sensor, replacement of a trim strip on the dashboard, and the aforementione 3 degree timing adjustment. The dealership also flushed the brakes at about 12000 miles to alleviate a squishy pedal.

One other thing to note, Here in Southwest PA, we are force fed oxygenated fuel from April through September.

I have already scheduled a return trip to the dealer, because the performance decrease is just unacceptible. I want to have the timing returned to spec. I'll mention the exhaust valve relearn. I really think the engine runs too hot, and would like to try a cooler thermostat and a cold air intake. (maybe just a z-tube and filter) I have also considered a coolant bypass on the throttle body as a last resort. I'm also going to talk to one of the techs, who I know does a lot of G mods. The service advisors think I'm a P.I.T.A. Their eyes just sort of glaze over when I start talking.

[SteveTheTech]

It certainly sounds like you have taken care of your G, sorry it's not returning the favor.

There is no exhaust learning proceedure on the automatic. So that is a dead end. The timing advancement really only effects base idle and not as much off idle. Like I stated earlier I understand your frustration and maybe being a pita is not a bad thing they will know what you are expecting. It is a hard call on this without seeing your engine numbers while running.

I'll see what I can find when I get a chance I wanted to get a quick reply back to you.

[TISon28s]

You should definetely start using 93 or higher octane. That chirping noise, is your engine knocking and building up carbon material.

[Sentientbydesign]

You should definetely start using 93 or higher octane. That chirping noise, is your engine knocking and building up carbon material.

On an 07?

SoCal only sells 91 octane and I've never had that problem. I think there is something else going on with his engine.

[haloseven]

I had the dealership reset the timing to "0" and requested some printouts of the engine at idle and under load. Unfortunately I think their version of under load is simply revving the engine in the service bay, not actually on the road and truly under load.

They gave me printouts of only the timing, no other parameters.

No load: corrected timing 0, 783 rpm, 15btdc

under load: corrected timing 0, 2563rpm, 21btdc

corrected timing 0, 2325rpm, 19btdc

corrected timing 0, 2588rpm, 14btdc

It seemed odd to me that the timing was so different with the rpm so similar. I wonder if they were at increasing or decreasing throttle...

I would have liked them to give more engine info, and to have checked it under a real load, and at different rpms. Sorry, I'm not too sure this is what you were looking for.

Of course, now that the daily temps here in Western PA have dropped, there is no longer any valve chatter, which strengthens my belief that this is somewhat temperature related. The dealer rep advised me not to lower the thermostat.

Is valve timing vacuum controlled?

[zozoka1212]

I don't think it is a good idea to put synthetic oil right at the start. You have to brake your engine in and put synthetic in. I don't know what the problem tho and sorry to hear your trouble. I would probably give my car to them and leave it for them to fix it. Tell them to give the car back to you when it is fixed. Ask for a loaner and enjoy it.

zozo

[zozoka1212]

I don't think it is a good idea to put synthetic oil right at the start. You have to brake your engine in and put synthetic in. I don't know what the problem tho and sorry to hear your trouble. I would probably give my car to them and leave it for them to fix it. Tell them to give the car back to you when it is fixed. Ask for a loaner and enjoy it.

zozo

[fbpem1]

Next dealer trip you have ask for a print out you need to specify what you want, all the sensors, coolant temp, a/f sen b1 and 2, ho2 sen b 1 and 2, maf voltage, calculated load, engine speed, timing, bank 1 and 2 alphas, etc, etc. Trust me all that stuff is there and you can record while driving the car, and print it out.

The 3 degrees of timing seemed very excessive to me as i will only go -3 degrees of timing in a I30 or I35.

I would be very interested to see these printouts from data monitor since i have never heard this issue that wasn't solved with 1 or 2 degrees of timing retardation, or they were running cheap fuel.

Now for the comment above 1 or 2 or 3 degrees of timing retard your not going to notice timing dosn't make power it breaks things in my experiance with tuning cars. I have always been conservitave on timing when tuning.

I want to see your exact grams per second under calculated load and your alphas and all your o2 sensor voltages.

Have you tried to take the matter into your own hands and discussing things with outside sources (other than the forum and your dealer) There is a nice datalogging tool that also pulls codes and fits right into your DLC its made my MSD called the Dashhawk. If things from the dealer don't go as planned and they won't copoerate with you you might want to look into that for seeing exactly what your sensors are doing.

Thats all i have for now. Backing the gap down on the plugs might help from the factory .043 to say maybe .036 but thats a lot of work just to see if something will work. Theres all sorts of things you can try from induction services to that. Do you know when this first started? do you remeber anything wierd about when it first started?

[SteveTheTech]

It sounds like they printed out the screen from CII where you change the timing control.

What we were asking about is a little more work for whomever is doing it. By looking for Calculated Load and ALPHA reading we are trying to see what the MAF sensor is seeing and the Air/Fuel ratio sensors will tell us what the output is.

I think this is going to turn out to be something simple, I do however thing that adjusting the timing is a band aid. The numbers as they are do not seem to be out of spec the timing does change under load.

Is valve timing vacuum controlled?

LOL, No Nissan/Infiniti has not used vacuum control for a very long time it's all computer controlled and computer monitored.

[fbpem1]

I think this is going to turn out to be something simple, I do however thing that adjusting the timing is a band aid.

you know as well as i do every engine is its own different beast and some need things others don't. Adjustments and tweaks and such.

Without seeing the car hearing the severity of it and doing my own tests i am going with backing down the gap on the plugs but starting with an induction service i would however first put a bore scope down there look at the valves and top of the pistion and the walls just for sh*ts and giggles. I would love to see a good high quality macro shot of one of your plugs if you get around to it yank one out and get a good digi and post up some pictures. cylinder 1 is the easiest to get to quickly without taking anything off.