Good day fellow Nico members, this is my first post on this site so I hope you will be patient with me.

I'll try and keep my situation as short as possible, so I bought my first car which is an 06 m35x with 154000km/96k miles. Changed the oil on it which was very dirty and missing about 1.5 quarts filled it with 5 quarts of fresh clean oil. I took it to the dealership to get general maintenance work done, changed transfer case, tranny, and differential fluids, changed coolant and had a "service engine soon light" I needed to get taken care of as I need this car to be reliable for the next few years.

Please note I never noticed any rough idle or starting issue and power loss within the short time I've driven the car. I also got the code read before hand at private garage it said p0021 "A camshaft position timing over advanced or system performance bank 2".

Dealer wanted to change a VTC solenoid to fix it. So I tell them to go ahead and do it. Next thing I get a call with a lot of details telling me that it didn't fix the issue and the light came back on and they timing isn't catching and I'm looking at a 2700$ job to fix it including the 1500$ I already racked up from the fluid changes and solenoid replacement. I told the service manager to email me the details of the situation and I am in desperate need of an opinion from a mature person who has more wisdom and experience than me. Also here is a copy of the email I received from the service manager outlining the situation:

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"As we spoke about on the phone earlier today, we replace the VTC solenoid which resolved the circuit issue for the DTC code. After roadtesting for driveability after this repair, the technician noted that there is a light engine miss and then the service engine light came on again for the P0021 code. The technician continued further diagnosis and completed the osciliscope testing determining that the timing is out be 20+ degrees. This electronic information determines that the timing chain has too much slack, damaged or worn teeth, the sprocket and guides would more than likely be worn also, so the estimate includes replacing all of these timing components. Once the timing cover is removed, then the exact required components would be confirmed. Given the age of the vehicle, technician suspects that this condition has been evident for a long time, however, it is now worn to the level that is effecting the driveability.

Labour 11 hours @ $124.95 = $1374.45 Parts @ $1451.49 the total including HST $3200.00 We have discounted the parts and labour by 15%. So the total with HST would now be $2715.00

Your current repair total including HST is $1533.00

Please advise of your decision in this matter."

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What would you do in this situation? Does it seem right what they are telling me in the email. My worst nightmare is if they do the work and it doesn't fix the problem. If any of you guys could help me out or give me some direction or opinion I would greatly appreciate it. If you need any more details please let me know.

It could be that something skipped a tooth or two and timing is now out. This would most likely happen from previous owner not doing maintenance properly in that area and not tensioning the chain properly. If it was me, I would take it to an independent shop and have them fix the timing. Only after this has been done if the code comes back and things are out of timing again would it mean parts are actually wortn and the engine is skipping teeth on the timing chain. I suspect it isnt, but rather from improper maintenance that caused teeth to skip some time ago.

Or the previous owner could have been trying to tune the car in a different way and deliberately changed timing for some reason. In super high end performance applications people do this sort of thing with adjustable timing on the camshafts to tune for a specific setup.

EniGmA1987 wrote: ↑

Wed Feb 20, 2019 5:01 pm

It could be that something skipped a tooth or two and timing is now out. This would most likely happen from previous owner not doing maintenance properly in that area and not tensioning the chain properly. If it was me, I would take it to an independent shop and have them fix the timing. Only after this has been done if the code comes back and things are out of timing again would it mean parts are actually wortn and the engine is skipping teeth on the timing chain. I suspect it isnt, but rather from improper maintenance that caused teeth to skip some time ago.

Or the previous owner could have been trying to tune the car in a different way and deliberately changed timing for some reason. In super high end performance applications people do this sort of thing with adjustable timing on the camshafts to tune for a specific setup.

I think I can rule out any previous owners trying to mess with it for performance applications based on owner history and just by looking at it. I also remember hearing the service manager saying something about skipping a tooth.

Hey enigma so if I could take it to an independent shop and they could correct the timing how would they do that anyway? Is it simply a matter of aligning the chain to the teeth or making minor or adjustments sorry I don't know much...& why couldn't the dealership try isntead of wanting to go ahead and replace all those parts right off the bat?

Judging from the condition and loss of oil, this was NOT a properly maintained vehicle and has likely been neglected for nearly 100k miles. By changing all the fluids, you have corrected this situation to a degree. I cannot recall any instances on this forum about this particular situation, so it is rare for this engine to have this issue. There is nothing wrong with getting a second opinion. You can take it to a mechanic of your choice. or a local Nissan dealer to have another diagnostic done. The VQ35 engine is a well respected, highly reliable engine, but if driven hard without proper maintenance could possibly have caused this issue.
If the car truly needs this additional repair, I would definitely have it done as soon as possible. I'm sorry to hear that you face such a high priced repair, but after it is fixed, you should be good to drive for another 100k miles.
Please keep us updated on your progress.

Larz wrote: ↑

Wed Feb 20, 2019 5:24 pm

Judging from the condition and loss of oil, this was NOT a properly maintained vehicle and has likely been neglected for nearly 100k miles. By changing all the fluids, you have corrected this situation to a degree. I cannot recall any instances on this forum about this particular situation, so it is rare for this engine to have this issue. There is nothing wrong with getting a second opinion. You can take it to a mechanic of your choice. or a local Nissan dealer to have another diagnostic done. The VQ35 engine is a well respected, highly reliable engine, but if driven hard without proper maintenance could possibly have caused this issue.
If the car truly needs this additional repair, I would definitely have it done as soon as possible. I'm sorry to hear that you face such a high priced repair, but after it is fixed, you should be good to drive for another 100k miles.
Please keep us updated on your progress.

Hi Larz, based on what I was told from the dealership previous owners have kept up on maintenace work, so not only does it seem rare it also seems weird and that's where I am having slight doubt with the dealership, I could be wrong though.

With regards to a second opinion that is also an option I could take it to Nissan and see what they say, it's just that if Infiniti is 100% honest and right about the situation I would go ahead and pay them but I don't know if they are 100% honest and right. I want to exhaust my options before I get to that point and cough up the money.

Also I will keep you guys updated and thanks for your input

I’m an M45 guy but this all makes me wonder why they didn’t just change the camshaft position sensor for bank2. If the timing was off, it would be off in Bank1 too, right?

The camshaft position sensor is about $100 and takes all of 2 minutes to replace. One 10mm bolt right on the front of the engine.

And another thing: that shop sucks. If they didn’t get it right on the first attempt and didn’t even try to work with you on pricing after being completely wrong, I would question that shop anyway. Why not just keep telling you it’s everything that it isn’t and charging you for it?

I don't like the people who have "fixed" your vehicle so far.

In the V6 engine, low oil usually triggers the camshaft codes. Combine that with the fact that the oil you drained was low and very dirty.
If the low level by itself doesn't set off some codes, the dirty oil will.

This is the sequence of events I'd have followed:
1. Is the oil low?
Yes - add oil and monitor code
For faster troubleshooting, erase it and see if it comes back... But it would go away after a while if it was indeed the issue
No - check for oil condition & cleanliness. [I'll continue this part at the end]

2. Is oil level good?
Yes - Switch the VVT sensors from left to right & monitor code as above.

3. Did the P0021 code now become a P0011 code?
Yes - the sensor was/is bad. Replace it or clean it if it is evidently gunked up
No - switch the left and right bank camshaft sensors. Any change to the codes?
Still no - proceed to next step

4. Remove the sensor and look into the signal generator (the teeth inside the hole). Any evidence of gunk build up?
Yes - wipe it or spray it off and monitor code as above
No - proceed to inspecting solenoid

Note:
There is a procedure to test the voltage & operation of the solenoids, but again these things are basically oil pumps, and their proper operation might be inhibited by gunk due to bad oil.
4. After cleaning the VVT solenoid, then you can proceed to replacement etc. The shop went straight to the very last thing you do in the troubleshooting sequence. Well, there might be timing issues too, but the car can normally adjust way beyond the 20 degrees they claim to have read. Maybe the solenoid is just stuck (but the replacement should take care of that possibility)
5. Unless you see a water pump replacement somewhere in the records, it is almost impossible to jump the teeth of the VQ35DE and not have timing chain rattle or other codes for the camshaft, misfiring etc. The timing is the last thing I would think of looking at, with the information we have currently.

#1. continued
Check this new oil that you poured in, and if it is very dirty again, consider running 2 batches of conventional oil for cleaning purposes, and maybe introduce seafoam or some other cleaner. I don't run any oil additives myself, just plain oil and rev it nicely to self-flush.

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It helps to have a code reader handy for such troubleshooting. Their prices have come down drastically, and would save you from having to make a trip to a store to erase the codes for you, if they will even agree to.

EdBwoy wrote: ↑

Thu Feb 21, 2019 12:14 am

The people you have taken the vehicle to so far, seem to be a bunch of Quacks. I have seen it mentioned that these days we don't have mechanics or true technicians, we just have parts changers.

In the V6 engine, low oil usually triggers the camshaft codes. Combine that with the fact that the oil you drained was low and very dirty.
If the low level by itself doesn't set off some codes, the dirty oil will.

This is the sequence of events I'd have followed:
1. Is the oil low?
Yes - add oil and monitor code
For faster troubleshooting, erase it and see if it,comes back... But it would go away after a while if it was indeed the issue
No - check for oil condition & cleanliness. [I'll continue this part at the end]

2. Is oil level good?
Yes - Switch the VVT sensors from left to right & monitor code as above.

3. Did the P0021 code now become a P0011 code?
Yes - the sensor was/is bad. Replace it or clean it if it is evidently gunked up
No - switch the left and right bank camshaft sensors. Any change to the codes?
Still no - proceed to next step

4. Remove the sensor and look into the signal generator (the teeth inside the hole). Any evidence of gunk build up?
Yes - wipe it or spray it off and monitor code as above
No - proceed to inspecting solenoid

Note:
There is a procedure to test the voltage & operation of the solenoids, but again these things are basically oil pumps, and their proper operation might be inhibited by gunk due to bad oil.
4. After cleaning the VVT solenoid, then you can proceed to replacement etc. The shop went straight to the very last thing you do in the troubleshooting sequence. Well, there might be timing issues too, but the car can normally adjust way beyond the 20 degrees they claim to have read. Maybe the solenoid is just stuck (but the replacement should take care of that possibility)
5. Unless you see a water pump replacement somewhere in the records, it is almost impossible to jump the teeth of the VQ35DE and not have timing chain rattle or other codes for the camshaft, misfiring etc. The timing is the last thing I would think of looking at, with the information we have currently.

#1. continued
Check this new oil that you poured in, and if it is very dirty again, consider running 2 batches of conventional oil for cleaning purposes, and maybe introduce seafoam or some other cleaner. I don't run any oil additives myself, just plain oil and rev it nicely to self-flush.

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It helps to have a code reader handy for such troubleshooting. Their prices have come down drastically, and would save you from having to make a trip to a store to erase the codes for you, if they will even agree to.

I have been doing my own research and this makes so much sense to me. I wish the technician could explain and outline/follow procedures like this instead of trying to make the quickest buck possible.

I filled it with Pennzoil Ultra 5w30 and got the p0021 code cleared but it came back within a couple days. After I got the solenoid changed at the dealer I'm assuming they also cleared it and when they took it for a test drive it came back. The car has been driven probably less than 40 km since changing the oil so maybe I should give it more time so it could clean things out and also do a couple more oil changes?

My concern is that if there is really a timing issue as they describe in the email could this lead to some sort of catastrophic failure if I leave it and continue driving. You say the system can adjust beyond the 20 degrees so maybe it won't be so bad and I think if something was serious I would also get another code thrown but it's just the p0021, no other codes, no weird noises, no shaking or loss of power, no hard starts in the short time I've been driving it. I will also ask for the service records to be emailed to me and see of any waterpump work has been done and maybe take it to Nissan instead if the oil changes don't fix it.

When I got the code read before taking it to Infiniti it said a camshaft position timing over advanced or system performance bank 2. Based on my research it could also be the camshaft sensor but couldn't that be ruled out by switching the bank 1 and 2 sensor? or maybe a cam sprocket is stuck or maybe it can be a ecm electrical issue or maybe a gasket issue. I don't know if they even checked oil pressure? Maybe do an idle relearn? I don't know I am throwing out ideas based on my own research.

Can you provide further input based on my response. Thanks. Oh and I forgot to mention the service manager was telling me if I don't get this repair done that it could affect the catalytic converter or something like that which could cost a thousand dollars to replace

Sstupid wrote: ↑

Wed Feb 20, 2019 7:52 pm

And another thing: that shop sucks. If they didn’t get it right on the first attempt and didn’t even try to work with you on pricing after being completely wrong, I would question that shop anyway. Why not just keep telling you it’s everything that it isn’t and charging you for it?

Yes that is my biggest concern, also I will ask them about what you said with regards to the camshaft sensor and see what they say.

If the parts are worn then I would ultimately want them replaced but from the testing they did using the oscilloscope could they be right even without removing the timing cover?

M35zzz wrote: ↑

Thu Feb 21, 2019 1:05 am

Oh and I forgot to mention the service manager was telling me if I don't get this repair done that it could affect the catalytic converter or something like that which could cost a thousand dollars to replace

Only if you get it done at Infiniti. With statements like that it seems more like they are trying to get you in for a thousand+ repair bill with fear tactics.
if you buy aftermarket high flow cats (around $400-450 for a pair, vs $1600 for a pair of OEM infiniti ones) and have them installed by a regular mechanic it would only cost you around $800-900 out the door and you get higher performance too. California ius the only state that the high flow cats will sometimes not work, but I know of a couple people here in the past who were even able to pass super strict CA smog check with hi-flow. So basically you can use them anywhere.
https://conceptzperformance.com/kinetix ... _31508.php
https://conceptzperformance.com/berk-te ... p_3091.php
https://conceptzperformance.com/torqen- ... _37972.php
https://conceptzperformance.com/aam-com ... p_2126.php

When I got the code read before taking it to Infiniti it said a camshaft position timing over advanced or system performance bank 2. Based on my research it could also be the camshaft sensor but couldn't that be ruled out by switching the bank 1 and 2 sensor? or maybe a cam sprocket is stuck or

Correct. That falls under "other troubleshooting steps". It is fairly easy to do, and especially since the car doesn't have driveability issues, I would be inclined to take time erasing codes and making small changes until I found the main issue.

Could you post all the codes that the car has had so far? Not the probable causes, just the Pxxxx numbers.

EdBwoy wrote: ↑

Thu Feb 21, 2019 1:51 pm

When I got the code read before taking it to Infiniti it said a camshaft position timing over advanced or system performance bank 2. Based on my research it could also be the camshaft sensor but couldn't that be ruled out by switching the bank 1 and 2 sensor? or maybe a cam sprocket is stuck or

Correct. That falls under "other troubleshooting steps". It is fairly easy to do, and especially since the car doesn't have driveability issues, I would be inclined to take time erasing codes and making small changes until I found the main issue.

Could you post all the codes that the car has had so far? Not the probable causes, just the Pxxxx numbers.

Told them to ahead with the job and take the timing cover off we'll see what they find and say -- they are also working to try and give me a further discount on the job. The only code the car was throwing was p0021 since I purchased it, before that I don't know unless there is a history database of some sort within the vehicle computer? Also based on service records Infiniti says the car was well maintained.

I pulled my own Carfax report and I see the previous owner was keeping up with oil changes up until a "front left" accident in february 2018. I remember he did tell me about this "fender bender" before I bought the car. Nothing seemed to serious.

Last oil change on carfax record was done end of January 2018. So it seems the owner stopped making oil changes after this front left "fender bender" up until I bought the car in August 2018. So that's 7 months without an oil change and also the oil change Valvoline service center sticker on the windshield say to be changed April 2018 or at 151000km. I purchased the car at 153500km.

I suspect this is why when I changed the oil it was very dirty and missing like 2 quarts. So maybe this caused the problem with the engine. Based on what service manager said car didn't seem to have any other problems and tranny, alternator are in good condition and I want to get another 100k out of this engine. Also based on my research some vq35de timing components will eventually wear so it would be worth it to me to get this over with now and done professionally. Will keep you updated.