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Misfire #7 again, again, and again...

4.6L (1996-2004 Modular) Mustang Technical discussions on 1996-2004 4.6 Liter Modular Motors (2V and 4V) within.

Misfire #7 again, again, and again...

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Old 09-16-2009, 12:11 AM
  #11  
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Originally Posted by sxynerd View Post

Snake Oil, stuff that claims to be miracle cures like hair tonic being sold by gypsies. lol
I've seen it work a few times, I'm not sure if there is any adverse affects though.
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Old 09-16-2009, 03:25 AM
  #12  
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OK I have to ask a question. What is the purpose of a oscilloscope? I have used volt-meters, noid lights compression gauges etc to diagnose misfires but never even heard to use an o-scope. I read a little about it but don't completely understand it for use on an engine. Seems like it would only work with sophisticated electronics. Do you use it just to see if the coil is putting out the same current/spark pattern as the other coils?

From my experience it's probably an intermittent wiring short, possbly even a faulty ecu. Both of which are fairly common with ford and dodge vehicles.
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Old 09-16-2009, 09:29 PM
  #13  
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Originally Posted by FrankenStangNPD View Post
OK I have to ask a question. What is the purpose of a oscilloscope? I have used volt-meters, noid lights compression gauges etc to diagnose misfires but never even heard to use an o-scope. I read a little about it but don't completely understand it for use on an engine. Seems like it would only work with sophisticated electronics. Do you use it just to see if the coil is putting out the same current/spark pattern as the other coils?

From my experience it's probably an intermittent wiring short, possbly even a faulty ecu. Both of which are fairly common with ford and dodge vehicles.
Well, with a scope you could examine the pulse going to the Cop or injector. if there's a resistance problem in the wiring the pulse might not be sharp (Square) causing the useable pulsewidth to be compromised.
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Old 09-17-2009, 03:54 PM
  #14  
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Originally Posted by marcuskeeler View Post
Well, with a scope you could examine the pulse going to the Cop or injector. if there's a resistance problem in the wiring the pulse might not be sharp (Square) causing the useable pulsewidth to be compromised.
You can measure parade and many other types with the scope. Not to mention depending on how much resistance there is, it will change how long or "big" the firing line is. It will tell you if there is a miss fire. The harder it is for the spark plug to ignite the fuel the bigger the line is the more dwell\resistance there will be. It's a magical tool

The analog ones are much more accurate than the digital but good luck finding one.
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Old 09-17-2009, 04:09 PM
  #15  
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It must have been the hand of god that made it go away but it has. IDK how. I'm going to do the compression test this weekend. The wife doesn't want me touching it till then, just in case she gets more bad news and I tell her she can't drive it till I replace another expensive part, lol.
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Old 09-17-2009, 04:40 PM
  #16  
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There is a good chance it will be back.
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Old 09-17-2009, 05:04 PM
  #17  
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Originally Posted by BOSTANG View Post
There is a good chance it will be back.
I don't doubt it, lol.
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Old 09-18-2009, 12:28 AM
  #18  
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my sugestion...i had some screwy connectors on my car. Wiggle all the wires on the injectors and the cops, i had 3 bad ones that inadvertanly would cut out whatever it was attached to, just wiggle and tug. Altho it caused short term problems then went away completly shortly after...musta created a better connection lol.
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