Any Help....[ignition misfire]


  #1  
Old 12-18-05, 11:01 AM
carriendoug
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Any Help....[ignition misfire]

I have a 93 chevy cavalier with an ignition misfire on cylinder 4. Its a 3.1 liter 6 cyl engine with three coils. The number 4 cylinder has had the wire replaced, but it still get no signal from the coil,, its had the coill replaced even though the number one cylinder with it fires fine, i have also replaced the module, and still no signal to the number 4 cylinder, i have checked for a tight engine ground, and am now officially out of ideas. Any help would be so greatly appreciated..
thanks
 
  #2  
Old 12-18-05, 02:03 PM
M
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question

I see you have done a wire swap and coil swap How about the spark plug itself have you replaced it?
 
  #3  
Old 12-18-05, 02:14 PM
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You should try grounding the plug wire on the opposite wire on the same coil .That system needs to have a complete circuit to operate properly
 
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Old 12-18-05, 11:12 PM
Z
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im not sure if im missing something here, but are you sure it is the spark, have you held the plug against the engine while someone cranked it to see if it is sparking. Could it be a bad injector, do you know if it is getting fuel?
 
  #5  
Old 12-20-05, 01:19 PM
carriendoug
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Thanks for the ideas everyone, but still have the same prob..lol i changed out the plug and the weird thing is that when i have a plug attached to the wire and watch for spark, it sparks fine, but when i place it in the engine, the wire has intermittant signal, per my test light, and all the other wires read great, did the module and yep changed the plug and the wire, and the coil. I had ths prob about a month ago with the 3-6 and when i replaced the coil the prob was fixed, but not this time on the 1-4. out of the engine good spark and signal to the wire, and plug, in the engine, cant see plug obviously, but intermitant signal to the wire goign to the plug. arghhh
 
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Old 12-23-05, 11:00 PM
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you should check number one wire as mentioned above by proworker, it can affect cylinder 4 as when the coil fires it actually is firing both plugs as the spark exits one terminal on the coil and reenters the coil on the other terminal to complete the circuit, the best way to check a wire without a scope would be to check resistance with an ohmeter it should be under 10,000 ohms per foot of wire.
what are you using to determine that you are losing spark when the plug and wire is installed and engine is running, if it is some sort of inductive device such as a timing light or a tester that you hold against the plug wire it is not an accurate way to check for spark and may be misleading you and the problem may not be spark related at all.
you should use a spark tester that clamps to ground and allows you to visually see the spark, the gap will be much larger than that of a sparkplug the reason for this is to add resistance similiar to what the coil has to overcome when its firing a spark plug under cylinder compression.
 
  #7  
Old 12-24-05, 05:06 AM
M
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just a bit of info

Many many years ago when I was in aircraft maintenance school we had a box thet we could pressurize it was a clear box.I think we were in iginiton systems.
Anyway in this box we would thread a known bad plug and it would fire fine with no pressure.When we applied pressure the plug would not fire.
This is what might be going on in your case
 
  #8  
Old 12-25-05, 05:33 PM
carriendoug
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thanks again for all the answers, this is way more help then i expected. I was told to never ground the 4 wire to the 1 wire, but i dont rely to much on the info i was given by this person. How would i go about grounding one wire to the other?? and what exactely does that mean, ground one wire to the other?? worth a shot, you all know more then me obviously..lol
 
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Old 12-26-05, 07:04 PM
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you just need to test cylinder 1 wire or replace with a known good one if you dont have an ohmeter to test resistance of the wire.
and you may need to get a spark tester if you continue to have problems after doing the above if you are going to confirm if it is a ignition related problem or if the misfire is related to something else.
 
  #10  
Old 12-26-05, 08:43 PM
carriendoug
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thanks again, today i did replace al lthe wires with new ones, and the same problem exists:-( there is a fuel smell coing out of the tailpipe, which could mean an open injector i guess, but i thought that would set off a code on the check engine, had a buick that did that when the number three injector went bad, and i have no codes at all which lead me in any direction other then igniton, but then, im so deep into this, i cant tell which way is up anymore..lol
 
  #11  
Old 12-27-05, 09:37 AM
Rick m
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Hope this ain't considered advertising...but this might be helpful.

Do a search for a "Cricket" under eBay Motors > Parts & Accessories > Automotive Tools > Diagnostic Tools / Equipment :
Diagnostic Tools / Equipment

This tool has helped me more than once.
 
 

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