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Infiniti I35 Maintenance and Repair

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Comments

  • wilson16wilson16 Posts: 20
    It usually is happening at acceleration. I always heard using Premium gas was a waste money but if that's my problem what gas would you recommend using
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    edited May 2011
    If it sounds like a chain dragging under the car when you accelerate, this could be detonation (pinging) and it is *very bad* for your engine, if it persists and is frequent and loud. (a little 'ping' for a split second is okay).

    Just buy the best gas you can for starters, like Shell or some other name brand, and see how it affects the noise. If it diminishes or goes away, you are on the right track. If it doesn't, you'd best see a mechanic to determine if it is really severe detonation requiring engine adjustments, or if it's some other noise not related.

    In any event, don't postpone acting on this. Severe detonation will punch a hole right through the tops of your pistons. :cry:

    The noise you are hearing are the internal parts of your engine rattling around---literally.
  • atma97atma97 Posts: 47
    Knocking sound in acceleration is a symptom of gas with low octane or engine running too lean. One should always use a premium gas for I35. If knocking sound exists after a couple premium gas tanks, then knock sensor need to be replaced ($50 part). For saving on gas, I am adding 3 oz of pure acetone into a 14 gal gas refill and saw mpg increase more than 3 mpg. I am doing this with my own risk but the car is running at its best. At 160,000 miles with a luxury and smooth ride, I could not find a just reason to get rid of this car and get a more luxury and trendy one. Hope not to keep driving this one for another ten years.
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    edited May 2011
    Acetone has been shown in rigorous clinical tests to have no affect on gas mileage, and is also corrosive to paint and rubber, so you could confidently abandon it with no worries. I personally never recommend using it. Probably you're experiencing normal variations in MPG and most of us don't have the patience to really measure and calculation out all the variables.

    Your suggestion about a knock sensor is definitely worth looking at and thanks for mentioning it.
  • wilson16wilson16 Posts: 20
    I have heard there may be more than (1) knock sensor in the 03-I35
    Can you tell me where the location or locations would be and is it something I can change myself
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    edited May 2011
    No just one. Looks like a bit of a job. Book says 3.5 hours for a mechanic. It seems to sit (from the diagram I've got) in the valley between the two cylinder heads--so under the intake---about 2/3rds of the way back. It's also a pricey little devil--not something you'd want to be guessing about. List price close to $200 bucks tho' I'm sure you could shop around and do much better.
  • wilson16wilson16 Posts: 20
    Well as such as all the parts for Infiniti. If the premium gas doesn't fix the knocking that I'm getting what would the signs be for a knock sensor going bad or about to. Are there any other places I might check to solve this problem
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    edited May 2011
    Well it would be good to get a "second ear" on this noise to make sure we're barking up the right tree...unless you are POSITIVE it's pinging.

    Anyway the knock sensor is supposed to correct for pinging--it's supposed to "hear it" and retard the engine timing. The question then becomes--is the knock sensor working or not, and if it IS, why isn't the engine responding to the signal?

    DESRIPTION: The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. This pressure is converted into a voltage signal and sent to the ECM.

    So in theory we could also have an electrical connector issue, or an ECM issue.

    Unfortunately I cannot find any description of how to diagnose and test for a bad knock sensor. I would presume a good repair shop with a CONSULT-II scanning device knows how to do this.

    They used to say "you don't have to be a rocket scientist to figure THAT out"--but you know, sometimes I wonder :sick:
  • atma97atma97 Posts: 47
    edited May 2011
    There are other reasons for the engine to knock when the car has high millage. Car might run too lean or too hot. Lean might due to dirty fuel injections or weak fuel pump. Hot might be caused by back up pressure from bad catalytic converters. I would exam spark plugs to figure out how lean the engine runs.

    Knock sensor is bolted to the center of the engine, underneath intake manifold body. As soon as removing the intake manifold upper and lover parts, you will see the knock sensor sitting right on the engine. You will need a new set of manifold gasket though. It might be a good idea to change valve cover gaskets and spark plugs when you have full access to these locations. The whole tedious job requires patience, try not to over tighten the bolts on this engine block. Hope you will have another 100k miles on your car after this job.
  • wilson16wilson16 Posts: 20
    Do you think the noise I may be hearing could be the timing chain getting loose or already that way. I've noticed that when you rev the motor you hear a clanging sound or when you shut the motor off
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    Sure could be chain noise from a bad tensioner. Usually you'd hear this more when the engine is 'slack' than when it is being revved but this could be diagnosed with a mechanic's stethoscope.
  • melansonmelanson Posts: 1
    Hi,I do not understand who you were talking to.I think they all just wanted your money or didn't want to help!We have gotten our tires for our I35 everywhere and were never told that!We have never had Bridgestone tires either. Firestone,townfair tire and sears have all put tires on for me within a half an hour:)Like i said,never heard of that and have never had a problem and our car is used for delivery all day everyday so we go through tires!
  • I have a similar issue w/ my '04 I35 (130K miles). I've noticed that the knocking sound happens mostly when I am only local roads probably on 2nd gear coasting at 2000rpm. I do not hear it when I'm on the highway. The interesting part is that this morning I had the "service engine soon" light come on. What do you recommend that I look at? Thank you
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    Well pinging only occurs under engine load. You wouldn't be getting pinging if you were coasting leisurely. In any event, scanning for a trouble code might give you some hints.
  • I changed the oil and found that it was low on oil even though the dip stick indicated otherwise. Drove about 5 miles to Autozone and had them scan the code and it indicates the camshaft sensor (P0011). Now I'm trying to find a diagram to locate the camshaft "A" sensor
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    I sent a diagram to you via e-mail.
  • wilson16wilson16 Posts: 20
    I have tried the premium gas and I still get the pinging or valve rattle which ever it might be
    I know the car has high mileage but it has been very well maintained.
    What I'm asking is what would anybody advise to look at next? knock sensor , camshaft semsor etc...
    Thanks
  • MrShift@EdmundsMrShift@Edmunds Posts: 43,633
    Yes could be any of those---you can have the timing checked with a timing light---but cam sensor, crank sensor and even a bad ECM can cause this problem. Also the timing chain could be worn, which would be unusual, but...

    The knock sensor is attached to the cylinder block. It senses engine knocking using a piezoelectric element. A knocking vibration from the cylinder block is sensed as vibrational pressure. This pressure is converted into a voltage signal and sent to the ECM.
  • I had the same problem turned out I just had to replace the timing chain/belt.
  • wilson16wilson16 Posts: 20
    That solved the problem completely? How many miles did you have on it when you had this done. This sounds costly!
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