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Jay, Certified Infiniti Technician
Category: Infiniti
Satisfied Customers: 20393
Experience:  20+years, Nissan and Infiniti experience and currently now working for a Infiniti Dealer
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Infiniti: Just been reading posts about rear timing gaskets.

Customer Question

Just been reading posts about rear timing gaskets. The issue I am having is more than likely related to oil pressure. Under acceleration when car is warm, the engine is definitely "off song" . Through pedal manipulation I am able to get back in tune, but If I lay off accel, then hit it again, engine is "off song" again. 221k miles, 16 track days. 322WHP Replaced Knock sensors thinking that was issue. Now thinking rear timing cover gaskets. They were replaced at 107k miles. Do you agree??
Submitted: 2 years ago.
Category: Infiniti
Expert:  Jay replied 2 years ago.
Hello my name is ***** ***** Thank you for your question.
What model Infinti is this? Also what codes are you getting? and what is the car exactly doing?
I don't understand what you mean by "Off Song"
Let me know
Customer: replied 2 years ago.
My car is a 2008 g35s sedan. It has 221k miles. It is in near perfect condition. There are several mods including intakes, Uprev, Stillen exhaust, blah blah. I have had multiple issues over the life of the car related to the VVT. Actually won LemonLaw case against Nissan. The seals inside the front timing covers go bad every 30-50k depending on how many track days. As far as what exactly the car is doing, here goes. Car idles as smooth as the day I bought it. Lately though, as the car warms up, the engine sound changes under load. Even the slightest increase in pedal pressure, and engine sounds as if there is a misfire, or like one side of engine is getting less fuel or air. Now, if I very carefully manipulate pedal, I can get it back in tune and can continue to accel and it drives perfectly normal until the time I slow down at all. If I mash pedal WOT even though car accelerates fairly well, and the misfire will continue all the way through the RPMs and the engine just doesn't sound right(lower tone). Another way to describe same issue is on highway, when cruising, car seems and sounds normal, but the slightest increase in pedal pressure, the engine note changes for about 500 rpm, then seems to correct itself if I keep pedal pressure constant and continue accelerating. There are no codes being displayed, front timing cover internal seals are new on both side. I replaced knock sensors three days ago. Oil never goes more than 3000 miles. Oil pressure at hot idle is 25, and at 2000rpm is 50. Rear timing cover was replaced 100k miles ago.... Any ideas?? Could it be the magnetic exhaust valve controller?? Driver side VTC cover is at least 150k miles. I swapped solenoids ( I have extras). I even put back on an older VTC on pass side. No difference. But definitely feels like some type of timing issue.... Let me know what else I can tell u. Thanks EP
Expert:  Jay replied 2 years ago.
Holly cow that is some description
Do you have access to a scanner to monitor short term fuel trim and intake timing?
Customer: replied 2 years ago.
I don't think so. I will check with a friend. Nothing in description sounds familiar??
Expert:  Jay replied 2 years ago.
Well some of it sounds like it could be due to the cold air intakes causing a imbalance of fuel trim. When you have a back timing cover gasket issue, you would get stalling issues or almost stalling. You really don't feel a performance issue.
Please check with your friend if he has a scanner to monitor fuel trim and intake timing. I do know that on the 08's you have a calibration for Exhaust Valve timing that is done with a scanner. If there is a back timing cover gasket issue if you had this done by the dealer and it completed, its not the back timing cover. If it doesn't complete, then it could be the back timing cover gasket.
Best thing for you to do is get a scanner if your friend has one to see if your fuel trim is with in spec. When ever you put cold air intakes on these cars, they run to lean and the imbalance of fuel trim is what can cause performance issues. You thing a cold air intake would increase performance, but it actually does the opposite on these cars. The cold air intakes cause a air vortex that the MAF sensors can't read properly and it meters air incorrectly.
If you have any more questions on this, please feel free to ask.
If not, and you're satisfied with my help, please Rate me. I hope I have provided you with Excellent Service.
Thanks Jay!
Customer: replied 2 years ago.
Jay. Just an FYI for your records... Issue was secondary timing chain tensioner on driver side. After 220k hard miles I had worn a grove into the tensioner piston and stretched out chain. That is why if I rolled onto throttle and built oil pressure gradually, it would pop up and be somewhat normal. But if I got on it right away it would never have time to tension correctly. I replaced all chains and tensioners, also upper oil pan (cracked). Fired right up. Saved myself over $4000 in labor. Took about 4 days. Thanks for your help.
Expert:  Jay replied 2 years ago.
That isn't what stretches the chain, but the chain stretching can cause that. I know, I have seen them stretch to the point where they are touching each other and the tensioner is fully extended.
Your welcome and thank you for using
Thanks Jay!
Customer: replied 2 years ago.
Real quick. Throwing p0021 and 0024. I am guessing that I may have put on new main chain off by 1 tooth on the driver side bank 2. Sound about right?? After OBDII reset immediate code. Just wondering before I take front cover off again. Thanks EP.
Expert:  Jay replied 2 years ago.
Did you disable the fuel system and turn the engine over a few times to prime the chain tensioners?