Misfires detected but getting spark.. Need ideas

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Nov 28, 2018 | 03:23 PM
  #1  
So I had misfires in Cylinders 5 and 8 and I discovered that both had wires that were bad. So I have replaced the wires and spark plugs. Now I'm getting misfires in 2 and 8. But when I put my spark adapter on them, they are both getting fire and the plugs are brand new. It is sputtering a and I can tell it's not firing, but my spark tester indicates that spark is getting to those plugs.

I've also added compression numbers I got today in all cylinders. 8 seems low and 1 seems high. But it shows there should be no worries of a head gasket problem, doesn't it?

ALSO, I have a P38 Range Rover engine in this Disco2 and not the terrible head gasket Discovery 2 engine.




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Nov 28, 2018 | 04:45 PM
  #2  
Bad injectors? How did the old plugs look? New plugs? Are they coming out wet? Black?
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Nov 28, 2018 | 05:18 PM
  #3  
8 and 7 most likely for blown HG. Low comp can be cause of misfire, but 2 and 8 are on the same coil and on the side of the internal winding on the coil. My guess is you have a bad coil.
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Nov 29, 2018 | 10:06 AM
  #4  
Quote: 8 and 7 most likely for blown HG. Low comp can because of misfire, but 2 and 8 are on the same coil and on the side of the internal winding on the coil. My guess is you have a bad coil.
The cylinders are getting spark from the coil. I thought maybe the coil was the culprit because I was getting misfires in #5 and #8. So I changed it out and got misfires in #2 #7 and #8. When changing out the coil I found the #5 and #8 plug wires were burnt sitting against the exhaust and that caused them to break. So I returned the coil and bought wires instead.
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Nov 29, 2018 | 08:57 PM
  #5  
Quote: The cylinders are getting spark from the coil. I thought maybe the coil was the culprit because I was getting misfires in #5 and #8. So I changed it out and got misfires in #2 #7 and #8. When changing out the coil I found the #5 and #8 plug wires were burnt sitting against the exhaust and that caused them to break. So I returned the coil and bought wires instead.
Swap the coils left to right and see if the codes move.
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Nov 30, 2018 | 09:26 AM
  #6  
Misfire does not mean there is no spark. It is not "miss spark"
Misfire means the combustion chamber did not ignite its compressed air/fuel mixture. Whatever be the cause. With coils producing proper voltage at the correct moment, still can have a broken/shorted spark plug, a disconnected spark wire, leaky insulation, coolant in the cylinder, no injected fuel, valve stuck, no compression...

Example : an injector with a loose intermittent connection can fail to inject fuel the moment it has to and there will be no combustion; or misfire.
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