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86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

Left key on, now won't start

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Old Sep 20, 2013 | 01:19 PM
  #21  
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Thank you all for your replies. The coil is within spec when I checked it's resistance. Is it possible to have a bad coil that checks okay with an ohm meter? I will check the timing and compression, but I don't think it's mechanical since it ran fine before my boneheaded move of leaving the key on. My fsm states not to leave the key on for more than ten minutes but doesn't say why. Thank you for the education. Most of my experience is with carbureted engines.
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Old Sep 20, 2013 | 08:42 PM
  #22  
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Generally, no, a coil will not test okay with an ohm meter and be bad. The voltage across it, and the resistance in the coil is what generates the high voltages to create sparks at the plugs so if the coil is good, the only other thing that can be wrong is the igniter module not giving proper voltages.

The igniter acts like a switch, connecting the coil (-) terminal to ground in order to charge the coil, then breaks the connection to fire the spark plug. If the igniter is 'on', charging the coil, it is carrying current to ground- multiply the resistance of the coil by 12v to arrive at the Amperes it is delivering. Without the airflow driving gives it, and the off periods where it's not grounding the coil, it will overheat and degrade.

This degradation means that instead of connecting the coil (-) to ground, "ground" will slowly become 1v, 2v, 4v, 8v ... above ground, and that means less current in the coil and a weaker spark.
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Old Sep 21, 2013 | 10:18 AM
  #23  
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Thank you Abecedarian.
I ordered an igniter. I Love this forum. My fsm doesn't explain how my ignition works nearly as well as you do.
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Old Sep 21, 2013 | 10:44 AM
  #24  
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Somebody buy that man a beer. He's the hero we've been waiting for. Let us know when you get that coil installed.
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Old Sep 21, 2013 | 11:59 AM
  #25  
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Originally Posted by jameslc9
... My fsm doesn't explain how my ignition works nearly as well as you do.
No substitute for Abecedarian, but check out http://www.autoshop101.com/ (Technical Articles / Ignition system) for good background information.
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Old Sep 21, 2013 | 05:04 PM
  #26  
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Originally Posted by abecedarian
Generally, no, a coil will not test okay with an ohm meter and be bad. The voltage across it, and the resistance in the coil is what generates the high voltages to create sparks at the plugs so if the coil is good, the only other thing that can be wrong is the igniter module not giving proper voltages.

The igniter acts like a switch, connecting the coil (-) terminal to ground in order to charge the coil, then breaks the connection to fire the spark plug. If the igniter is 'on', charging the coil, it is carrying current to ground- multiply the resistance of the coil by 12v to arrive at the Amperes it is delivering. Without the airflow driving gives it, and the off periods where it's not grounding the coil, it will overheat and degrade.

This degradation means that instead of connecting the coil (-) to ground, "ground" will slowly become 1v, 2v, 4v, 8v ... above ground, and that means less current in the coil and a weaker spark.


Just fantastic posting. Makes me cry a little...
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Old Sep 21, 2013 | 09:40 PM
  #27  
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Honestly, no one will know if I'm correct until the igniter arrives and the engine fires.

If it doesn't, I'm in trouble.
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Old Sep 21, 2013 | 09:52 PM
  #28  
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Old Sep 21, 2013 | 10:11 PM
  #29  
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Originally Posted by Kiroshu
Okay, you're scaring me.
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Old Sep 22, 2013 | 09:40 AM
  #30  
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^-- Haha.



Its cool. More or less just hovering around waiting on results.
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Old Sep 24, 2013 | 05:22 AM
  #31  
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Lol. I'll let you all know as soon as the ignitor is installed. I love this forum. : )
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Old Sep 29, 2013 | 07:20 PM
  #32  
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Hell, I've read this whole thread and I'm wondering what will happen
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Old Sep 30, 2013 | 11:59 AM
  #33  
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I'm still waiting on the ignitor to arrive. The first part that came was wrong. It should be here tomorrow. I'm so ready to have my truck back.
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Old Sep 30, 2013 | 08:13 PM
  #34  
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Originally Posted by jameslc9
I'm still waiting on the ignitor to arrive. The first part that came was wrong. It should be here tomorrow. I'm so ready to have my truck back.
Queue suspense music....

/me grabs popcorn.

Last edited by abecedarian; Sep 30, 2013 at 08:30 PM.
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Old Sep 30, 2013 | 08:42 PM
  #35  
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Is there some kind of afterparty if this thing works out? /me grabs popcorn
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Old Sep 30, 2013 | 09:21 PM
  #36  
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Originally Posted by vasinvictor
Is there some kind of afterparty if this thing works out? /me grabs popcorn
Here, have some of mine.




Last edited by abecedarian; Sep 30, 2013 at 09:26 PM.
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Old Oct 1, 2013 | 01:17 PM
  #37  
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Unfortunately not yet. I installed the new ignitor, but it still won't start. I tried another coil (used), but the results are the same. The distributor air flow meter check out okay with an ohm meter. Dang
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Old Oct 1, 2013 | 01:23 PM
  #38  
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the distributor "and" air flow meter check out okay with ohm meter
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Old Oct 1, 2013 | 05:19 PM
  #39  
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I'm still leaning toward a "flooded" condition.

Hook-up a jump box to the battery and or another source to aid your trucks battery in excessive cranking time, and try to clear out the engine VIA "cranking and throttle application several times."

It may take several attempts.
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Old Oct 2, 2013 | 12:43 AM
  #40  
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Yellow spark, different coil, different igniter, cranks at 'normal' speed.
Spark should be bluish, and if the coil tests okay, and a substitute performs the same, that leaves the igniter not delivering proper voltage (or rather ground) to the coil... and if that doesn't work...?

I'm seriously at a loss here.
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