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Misfire, Compressions good, new wire & coils, Now What?

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  #11  
Old 04-01-2014, 09:29 PM
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You make a good point about the connector. Which connector would just affect one cylinder?

But it happened the afternoon after the engine cleaning, which is very suggestive. It would make me very slow to think worn lobe or another mechanical issue. Electrical is much more likely.

Injector is a good place to start. I'd also probly break out the wiring diagram to check all the wiring that affects the spark and fuel flow to #5.
 
  #12  
Old 04-02-2014, 08:05 AM
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If you have it narrowed down to one cylinder then i'd say swap the plug wire too and see if that changes the missfire... if not and the plug/coil/spark and compression are good, it leaves the injector.

i was suggesting putting the dielectris in the cps sensor. plug or anything else down there that might often get wet.
 
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Old 04-02-2014, 08:44 PM
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Its the Bosch plugs. If you check the resistance on them, they will be all over the place. Go with an Autolite/Champion/NGK plug with low impedance. less than 2500 ohm's. I like the Autolite Xtreme Performance Iridium. XP3924 is the number for disco 2's
 
  #14  
Old 04-03-2014, 12:43 AM
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He hasn't been back for 2 or 3 days now. I'll bet it dried out good and returned to normal. I dont wash my engines...Who cares if its dirty? I'm not about to enter a car show... and who needs an extra headache that getting all that stuff wet could bring on...
 
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Old 04-03-2014, 02:34 PM
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No nothings dried out and the Rovers still down. I haven't had time to try the injector yet but I'll probably get started tonight. I'm going to try new plugs first though
 
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Old 04-03-2014, 10:19 PM
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Ive done literally all you did and my CPS was bad, worked then didn't, then did, then didn't.... drove me insane


I did wires, plugs, coil, and CPS was the last piece. Its like 60 bucks, fail rate of every 5 or so years I heard on here. My 2 cents.
 
  #17  
Old 04-04-2014, 01:18 AM
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I know of a guy who had misfire issues. He swapped plugs, wires, etc but the problem stayon on the same cylinder. After some more trouble shooting he replaced all of the injectors but still had the same misfire. He finally noticed that the back of one of the fuel injection wires, close to the injector, was rubbing and it was shorting out.

Once he repaired that part of the wire his misfire was gone.

Something to consider when trouble shooring your misfire, pay really good attention to the wires for the injectors.
 
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Old 04-04-2014, 09:33 AM
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Originally Posted by GURU06
I know of a guy who had misfire issues. He swapped plugs, wires, etc but the problem stayon on the same cylinder. After some more trouble shooting he replaced all of the injectors but still had the same misfire. He finally noticed that the back of one of the fuel injection wires, close to the injector, was rubbing and it was shorting out.

Once he repaired that part of the wire his misfire was gone.

Something to consider when trouble shooring your misfire, pay really good attention to the wires for the injectors.
Thanks for the advice I will definitely go through the harness before I put everything back together

Originally Posted by gpelite
Ive done literally all you did and my CPS was bad, worked then didn't, then did, then didn't.... drove me insane


I did wires, plugs, coil, and CPS was the last piece. Its like 60 bucks, fail rate of every 5 or so years I heard on here. My 2 cents.
If the injector and wire harness check out, then this is my next step
 
  #19  
Old 04-05-2014, 10:15 PM
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Ok found the problem, almost. My exhaust valve is not opening on cylinder 5.
When I was checking the fuel injector I figured I'd pull the Valve cover and rotate the engine. My intake side opens but the exhaust side doesn't. I was able to move the valve with a pry bar and watch it come back up so it's not a stuck valve. Now I'm down to a bent push rod, hydraulic tappet is bad, a clogged channel going to the hydraulic tappet or a worn lob on the cam.

I don't think its a worn cam as this was sudden and the I don't think its a bent rod but I'm going to pull them just to make sure. I'm leaning towards the tappet or a clogged channel to the tappet.

Do you guys know how I can check the channel to the tappet?
 
  #20  
Old 04-06-2014, 01:13 AM
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And there it is....(see pic) Pulled the lifter out and its worn bad. Turned the engine around 3 or 4 times (just to be sure) and the lobe on the cam is gone too.

I'm guessing the valve was stuck closed and caused this..? Whatever it was it happened quick. Anyways... the Rovers done. I'm not going through the crap to replace the cam. Parting out a Land Rover in Denver, CO.
 
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