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High RPM Pinging

Discussion in '2011-2014 V6 Mustang Tech' started by Dave Stone, Sep 30, 2014.

  1. Dave Stone

    Dave Stone New Member

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    Hello, I have a 2007 4.0 which recently had the heads resurfaced, the thermostat housing replaced ( again ) and the O2 sensors replaced. It just passed smog but the idle is still a little rough and it pings at high RPM's. Someone mentioned to me the knock sensor and I was thinking of also changing out the spark plug wires for the idle possibly. Looking for any suggestions. Thanks.
    Dave
     
  2. Phil II

    Phil II Cone Destroyer Staff Member

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    Welcome Dave. We'll try to help you out.

    I've some questions up front:

    1) manual or auto?
    2) what isn't factory?
    3) how many miles on the chassis?
    4) please elaborate a little on the "pinging"- when, what it sounds like....?
    5) what octane of fuel do you normally use?

    I'm surprised that you didn't hit the periodic maintenance items as the heads went back on. The spark plugs and wires do degrade over time. Swapping those out and paying special attention to plug gap can help, The coil pack also has a limited life span. I'd change the fuel filter too.

    You might consider a colder spark plug. When the heads were resurfaced your static compressions was bumped a little bit up. I'd not normally think this necessary, but the pinging has me wondering.
     
  3. Dave Stone

    Dave Stone New Member

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    1) Auto
    2) I've put in a cold air intake and also recently changed the coil pack
    3) original chassis
    4) the pinging is a higher pitched ping and happens either when I'm parked or right before it shifts gears
    5) I usually use 89

    I had the car repaired by a friend of a friend out of his garage..full time mechanic doing side jobs.. He did replace the plugs but not the wires, I'm going to do that today. As I mentioned, I replaced the coil pack a few months ago but ever since this car blew it just hasn't quite been the same, I'm surprised that it passed smog. The plug gaps are set at .052. I've had two compression checks on it..all good. I've had a leak test done..also all good. The cat is fine so I'm going to change the plug wires for now and hope for the best.
     
  4. Phil II

    Phil II Cone Destroyer Staff Member

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    Pull one of plugs and check the part number. It might be nearly the right heat range.

    If you used 93 octane does the pinginig still happen?
     
    Last edited: Oct 1, 2014
  5. Dave Stone

    Dave Stone New Member

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    I put 91 octane in it today, added some Lucas oil and changed the wires and the pinging went away. Interesting. If it comes back I'm going to change the plugs again like you suggested.
     
  6. Dave Stone

    Dave Stone New Member

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    I do have another question; as I mentioned, this is the second time that the thermostat housing cracked which tells me that one, it's cheap plastic and two, that I have a overheating problem. Would changing to an aluminum radiator improve this situation or am I wasting my money? I want to do everything possible to prevent this from happening again.
     
  7. Phil II

    Phil II Cone Destroyer Staff Member

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    The radiator should already be aluminum. It may have plastic shrouds and side tanks, but the business end is aluminum.

    A couple of things to consider are:
    -degraded water pump performance
    -blocked radiator passages
    -a non-ideal mix of anti-freeze and coolant
    -cooling fan issues
    ....I could go on throwing stuff out there.

    I think the biggest thing was stepping from 89 to 91 octane. I suppose you're in California? The higher octane fuel will burn better and deliver more power and efficiency over the 89 octane. There will also be less waste heat for the cooling system to deal with. I don't know what the difference will be in your wallet, however I encourage you to consider running only the 91 octane. This article may pique your interest.

    As for the thermostat housing, you might look at this thread and this product. I found this with google, use your judgement.
     
  8. Dave Stone

    Dave Stone New Member

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    Yes, I'm in California, about an hour north of San Diego. Thanks for the links and suggestions I'm going to proactively stay on top of this and check each of these possible issues that you mentioned. Thanks again for the help.