Good question. I'll have to check the records again. It had been replaced twice in the car already (currently on 3rd tensioner). I believe the last one was the longer one, but unsure right now.

 

When they replaced mine they said the part had been updated in the past 6 months, but I'm not quite sure what was updated.

 

When did you have yours replaced?

 

2 weeks ago.

 

Well, still waiting to do the Dyno run, it seems everybody's dyno is broken in one way or the other. So I'm still playing the waiting game.

 

Hello all. I know this is quite an old thread. My 2010 has done this a few times within the last month or so, most recently a few days ago on the highway. I did get the hesitation in throttle response, some black smoke coming out of the exhaust, and a clicking sound (like a stripped out plastic gear would make). Am I safe to say that this is related to the timing chain tensioner? Is it just the tensioner bolt?

 

Basically I have had multiple answers. And they're all just about correct in their own way. The main explanation can be found here: https://en.m.wikipedia.org/wiki/Low-speed_pre-ignition

Basically this kind of behavior is inherent to our DI engines. The more mods you do the greater your behavior can be. Many other things also attribute to this behavior such as temperatures, humidity, altitude, ect.

If you're still on a stock tune that can be one reason. The stock tune is very lean compared to a higher level tune. This is mainly to help reach fuel economy and emission standards.

If you have a tune and this happens regularly, then you need your tune adjusted or changed all together. I switched tuners and adjusted driving style (read more on this further down) it almost never happens now.

Carbon build up on your intake valves can also contribute to preigniton by heating up the air just before going into your combustion chamber. The air intake temperature is read well before it actually goes into your engine. So the intake temp reading will actually change by the time it makes it inside your engine if your valves are comes up enough that the carbon build up is retaining the heat from your engine. This temperature difference can confuse the car too.

Carbon build up in your combustion chamber can also attribute to pre ignition. This can slowly. Very slowly. Be remedied by using a high end fuel system cleaner. I recommend BG 44k. It works and will clean your chamber. Be aware no cleaner will clean your intake valves because of the Direct injection design. (No fuel actually passes over the intake valves). Now these cleaners may take several fuel ups to fully clean those chambers out. I mean several. It will depend on how bad they are to begins with and if your engine is consuming oil. If you are consuming oil, most of it ends up in your chambers and burns. Usually this is caused by a bad PCV valve (built into your valve cover) or your valve seals are damaged. The valve seals are usually damaged by the coked up intake valves. (Like mine).

Now that I have gone through all that and you've read up all about LSPI, the easiest way to avoid this happening is to stay in lower gears. Don't up shift too soon and the engine load vs engine speed (rpm) will be in its happy place. Down shift to pass. 5th and 6th gears are not for passing (unless you're going over 100). If you're on the highway doing 60-70 you can drop to 4th. Just blip the throttle, shift, and zoom past.

I've done everything (including going back to stock) and if I really want, I can still make it happen. Just be cool , don't up shift too soon. Use top tear fuels. 91 octane or better. Keep your valves clean. Run a cleaner every once in a while. Fix what's broken. All of these things together will keep your engine running.

Hope this gives you, and many others I'm sure, some answers.

Please feel free ask if you have further questions

Chris

 

Thank you for that detailed explanation! I greatly appreciate it. I am running a nM stage 2 tune on my car and running one step colder plugs. I believe my car is starting to consume a bit more oil as well within the last year or so. Thank you again!

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