Possibly detonation...help

Discussion in '1994 - 1995 Specific Tech' started by Ryleighsdad, Feb 4, 2013.


  1. modulistic

    modulistic Member

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    wow sorry man, i was feeling confident that it was a timing thing. thats crazy.
     
    #21
  2. Ryleighsdad

    Ryleighsdad Member

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    Well now that you bring it up it does use a little oil (low oil light comes on after about 2 months). I never see it smoking and dont smell burning oil, and I have ZERO leaks. I have looked everywhere.

    No offense taken. Im looking at the timing pointer as shown in the photo below (not my engine).

    Shear key looked fine and new balancer went on smoothly with no force needed.

    [​IMG]
     
    #22
  3. WhiteCobra95

    WhiteCobra95 Member

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    Yep, you got the right mark so I think you have the timing set correctly. From what you’ve posted, I don’t think there’s much left to test on the ignition system side.

    For the oil consumption, there are a couple of things to chase after: 1) Replace the PCV valve and see if the line has a significant amount of oil in it, there's always a little bit but if oil pours out it's probably too much. Check to see if the old valve is stuck open. If the PCV is bad then you're intake probably has a bunch of oil in it, and it might take a couple of drives/warm-up cycles to clear it out. 2) Pull the plugs and see if they look like they've been burning oil. See if they're black and wet (like sludgy). If they're tan then it's perfect, and even they're a dry black carbon color that's good too (and a sign that you're having fun with your car!). 3) If they are sludgy black and the PCV valve doesn't fix it, then it's time for a compression and leak-down test to make sure that your rings are still good. 4) If those two tests check out, it might be the stem seals but I don't think the symptoms line up with that failure mode.

    Keep us posted and good luck.
     
    #23
  4. ratio411

    Founding Member

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    It's been a while since I posted on this thread.
    Did I ask about your spark plug heat range? Or has that been covered at all?
    Too hot on the spark plug heat range can cause detonation in itself.
     
    #24
  5. Ryleighsdad

    Ryleighsdad Member

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    I got the motorcraft plugs recommended by the haynes manual. Not sure what the heat range is or the part number, Ill have to look. Its only doing it sometimes now. I ran it today and it pulled hard all the way through 2nd and 3rd with no pre-ignition. I think Im getting there.
     
    #25
  6. WhiteCobra95

    WhiteCobra95 Member

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    Too hot of a spark plug will cause pre-ignition but not knock/detonation. Thesse get confused all of the time. Knock is bad and pre-ignition is much much worse. Pre-ignition sounds like mega-knock and an engine will only tolerate a couple of them before it blasts a hole in the piston. Long term knocking however can result in pre-ignition by building a hot spot in the chamber, but that's usually more toward the periphery of the cylinder away from the plug.
     
    #26
  7. WhiteCobra95

    WhiteCobra95 Member

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    That's great news! Hopefully it won't come back.
     
    #27
  8. Ryleighsdad

    Ryleighsdad Member

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    This was just like a ticking, sometimes it was worse, sometimes not so bad.
     
    #28
  9. Ryleighsdad

    Ryleighsdad Member

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    Ok, so its back with a vengance. It used to be kinda random when it started, but now anytime I go over about 1/2 throttle at low RPM and 3/4 throttle at high RPM. I am getting some serious noise.

    Its not super loud, more like a Rhythmic ticking.

    I hooked up a vacuum gauge today and I am getting 18in at idle, but its not steady. It fluctuates between 18 and 17. If I do the snap test it goes up to 27 then slowly down to 16, then back to 18 and resumes the fluctuation. I think it has always done this because it has always idled rough with a very slight surge. IIRC this hints to an ignition issue or a fuel pressure issue.

    I will test fuel pressure at idle and running tomorrow to see if the pump is headed out the door. I hope its not because I dont have money to replace something that wont fix this problem.

    I will also have a friend of mine put it on an ignition monitor and see whats going on with that side of things.

    Also today I got ****ed off and ran the hell out of it in 1st gear sliding. At about 5500 RPM, it started backfiring out of the intake again.

    Im sick of this ****! Bout ready to sell this thing.
     
    #29
  10. Ryleighsdad

    Ryleighsdad Member

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    FOUND THE PROBLEM!

    I just read on another forum that if you unplug the MAF, the computer will compensate and run a "safe" tune. So I unplugged it and went for a ride. NO MORE PINGING! So the MAF is either dirty or bad!

    Woooooooooooooooooot!

    I "cleaned" the MAF sensor by spraying it with cleaner, but Im not sure that was good enough. Tomorrow I am going to remove and clean it to see if that fixes the problem. If not, time for a new sensor!
     
    #30
  11. toyman

    SN Certified Technician

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    I believe it's called "limp mode" but "safe mode" conveys the same meaning. The MAF signal is the number 1 priority sensor as the signals from the MAF and the AIT are used by the computer to calculate the fuel load so as to maintain the correct AFR. Without a proper/accurate MAF signal the computer adds extra fuel. Better rich than lean strategy.
     
    #31
  12. Ryleighsdad

    Ryleighsdad Member

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    Ok, well I was wrong...I cleaned the MAF, and put the timing back to 10*. Problem is still there...fuel pressure test next I guess.
     
    #32
  13. Ryleighsdad

    Ryleighsdad Member

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    I think I may have found something. I realized that this particular problem didnt start until after I installed the new distributor. So I pulled up a picture online.

    I have made a yellow line on the two pictures showing where the #1 plug wire is pointing on the engine. Mine and the other picture are drastically different! Please ignore the numbers written on my cap. I know they are wrong. The wires to go the right place!

    IS MY DISTRIBUTOR STABBED WRONG?

    Photo of an engine I found on google.
    [​IMG]

    Photo of my engine.
    [​IMG]
     
    #33
  14. SableSal

    SableSal Member

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    Dude, looks like it's 180 off? My #1 is closer between the two bolts at the intake plenum... I'll have to check tomorrow morning, but I think it's stabbed wrong. Do yourself a favor and turn the crank to TDC and then take the distributor cap off and re-stab it. See where it lies.

    Everything is correct on this write-up minus the 10deg BTDC. Just mark it RIGHT AT TDC.

    http://forums.corral.net/forums/5-0-5-8-engine-tech/1291083-stabbing-distributor-101-a.html
     
    #34
  15. ratio411

    Founding Member

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    No!
    Don't go by other people's engines!

    You are probably on, don't worry if you are not in the same place as 1 on other cars.
    If you clock the wires, number 1 can be ANYWHERE on the distributor you like, and does not have to be one set spot!
    Stand down and look at this with a clear head.

    Check your placement of number 1 to confirm you are correct, before pulling the distributor.
    If you are on, no harm done, you have just taken the time to confirm.
    If you are off, then start from scratch and expend time on resetting the distributor.
     
    #35
  16. ratio411

    Founding Member

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    Oh, and if you do find that your rotor button is significantly off of the posititon of #1 wire, you can just move all your wires in the same direction to make a 'new' #1 position on your distributor cap that meets the rotor button on TDC. This is quicker than restabbing the distributor, and does the exact same thing.

    HOWEVER, I doubt you will find anything.
    The fact that your spark going to plug #1 mechanically lines up with the timing pointer means that this is almost impossible. You would have to be EXACTLY 180* out of time for this to happen, and you can bet a little detonation would be the least of your issues if that was the case.
     
    #36
  17. ratio411

    Founding Member

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    Are these 2 pics supposed to be showing us they are different, or the same???
    Are you saying there is a 3rd pic with the #1 wire in the yellow line position?
    I am having trouble following you.

    How about showing us a pic of YOUR distributor cap like it is now, with a yellow line added to show your current #1 spark plug wire in that picture?

    The bottom pic is yours, correct?
    Repost that same pic, with a mark showing us which wire is #1...
     
    #37
  18. ratio411

    Founding Member

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    Your pics have me confused as to the fact that the yellow line in both seems to point to #5 cylinder...
    You do know that #1 is the first cylinder on the passenger side of the car, correct?
    If you are timing #5 spark plug wire while looking at the timing marks on the balancer, you are going to have your timing advanced about 15* more than you think, which will cause detonation.
    Edit:
    That is with the 289 firing order... 15426378.
    The 351 order (5.0 HO), is different, and it would surely be more than 15*, so take this with a grain of salt.
     
    #38
  19. ratio411

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    Depends on how far out of range your plug is.
     
    #39
  20. toyman

    SN Certified Technician

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    That can only be true if the crankshaft and camshaft are also correct with the piston at the top on the compression stroke with both valves closed. Since it came from the factory with the rotor pointing at about 1'oclock under these conditions the OP is best advised to maintain the same orientation.
     
    #40

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