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Old May 24, 2020 | 07:39 PM
  #16  
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Originally Posted by F1001975
5V at run. 8V at start. Using the blue wire.




That is not right.
Below is the wiring for the Black module. So be sure we are talking about the same blue wire.


 
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Old May 24, 2020 | 07:47 PM
  #17  
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From: St Albert, Alberta
Originally Posted by F1001975
Coil numbers.
The numbers in the box to the right are 4KBA


Coil looks to be orginal Ohm it out to verify it is in spec.
Primary on the 200 Scale 1.0 - 1.7Ω
Secondary on the 200 Scale 6.5k - 14.5kΩ
 
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Old May 24, 2020 | 07:56 PM
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From: SWPA

 
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Old May 24, 2020 | 08:14 PM
  #19  
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it will be on the 3 Wire plug. And should be as below.




 
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Old May 24, 2020 | 08:31 PM
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OK thanks. I will check tomorrow.
 
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Old May 25, 2020 | 05:29 PM
  #21  
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From: SWPA
4 at run.
-.25 at start



When I ground to the chassis I get
11.3 at run
8.1 at start


Coil
1.7 primary on the 200.
nothing secondary on 200
8.7 secondary if I use the 20k scale
 
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Old May 25, 2020 | 05:53 PM
  #22  
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Where were you grounding for the first test? And what are your readings at the battery during the same times?
Your voltage readings are all over the place, which I would think means there is a wiring issue more than a component issue. But I'm not good on electrical theory stuff like the others are, so wait for cooler minds to prevail.

But 11.3 initially is maybe ok for the resistor wire (it has to heat up sometimes before it settles down to it's low voltage reading) but it's too low for the battery if that's what you're reading. If the engine turns over quickly with the starter though, the battery and cables seem to be good.
The 8.1 at START seems off too, since it should go UP during start. That's why I asked about what your battery is reading while the starter is cranking.

Paul
 
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Old May 25, 2020 | 05:57 PM
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When I did the first test I just put my probes directly into the slots I put the red wire Into the Blue slot and I put the black wire into the black slot.

on my second test the one with the higher numbers I put the red one Into the Blue slot and I put the black one on the chassis.
 
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Old May 25, 2020 | 06:04 PM
  #24  
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Battery reads 12 at run.

10 at start
 
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Old May 25, 2020 | 06:10 PM
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Well bummer. But at least that's not part of a no-spark problem.
Either the cables are getting old, the battery is going dead (in spite of a 12v reading), the starter relay is going bad (very common) or the starter itself is getting old.
Many new parts get old before their time nowadays, due to poor quality.

The only other thing that I can think of that might be related to the two things together, would be if the ignition advance was suddenly so far advanced that the starter was having a hard time turning the engine over. But that's usually noticeable when cold, because you'll at least hear the starter try to crank the engine before you hear the clicking.

By the way, is it just a single click at the relay? Or are you getting the multiple fast machine-gun clicks?

Paul
 
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Old May 25, 2020 | 06:17 PM
  #26  
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It's a single click but it's sort of intermittent now. I can get it to crank.
 
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Old May 25, 2020 | 06:30 PM
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Here's another weird one and I'm wondering if the ignition switch has something to do with it I just noticed now that even if you turn it off and pull the key out the low fuel economy light stays on ....don't mind the alternator gauge is never moves from where it is.


 
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Old May 25, 2020 | 06:37 PM
  #28  
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And here's another thing when they key is out of the ignition and it's definitely off the electric fuel pump is building pressure.


I'm really starting to suspect the ignition switch... or is this a common occurrence with the ignition module going bad???


I have a battery switch I always disconnect whenever I'm not around the truck so I'm not worried about electrical fires when I'm not here
 
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Old May 25, 2020 | 06:51 PM
  #29  
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Originally Posted by F1001975
4 at run.
-.25 at start



When I ground to the chassis I get
11.3 at run
8.1 at start


Coil
1.7 primary on the 200.
nothing secondary on 200
8.7 secondary if I use the 20k scale

Ok lets be clear here. You are having a No start issue NOT a NO crank issue. Correct ?


As for your tests The blue should be tested to chassis ground or Bat Negative. NOT the ground in the plug.

But you seem to have a ground issue in the harness. The Black is the ground for the module and it grounds in the Dist. So do a continuity test between the Dist housing and the plug. You may need to fix that ground Lose that ground and the module may quit working.

Looks like you are getting the correct voltage on the blue wire though.

And since you are getting other issues that would be related to an ignition switch issue, I would suggest you fix that first. Likely the switch is toast. Not an uncommon. thing. You will need to pull the tumbler from the switch when you replace it. They are not expensive so I would go that route. They are available from multiple sources

https://www.cjponyparts.com/f-100-ig...itches/c/4789/
 
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Old May 25, 2020 | 07:12 PM
  #30  
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Originally Posted by matthewq4b
Ok lets be clear here. You are having a No start issue NOT a NO crank issue. Correct ?


As for your tests The blue should be tested to chassis ground or Bat Negative. NOT the ground in the plug.

But you seem to have a ground issue in the harness. The Black is the ground for the module and it grounds in the Dist. So do a continuity test between the Dist housing and the plug. You may need to fix that ground Lose that ground and the module may quit working.

Looks like you are getting the correct voltage on the blue wire though.

And since you are getting other issues that would be related to an ignition switch issue, I would suggest you fix that first. Likely the switch is toast. Not an uncommon. thing. You will need to pull the tumbler from the switch when you replace it. They are not expensive so I would go that route. They are available from multiple sources

https://www.cjponyparts.com/f-100-ig...itches/c/4789/
okay at first I was getting a no-start issue then during all this disconnecting wiring and everything I got a no crank issue but I rechecked all my connections and that it seemed is going away.
So it cranks fine now.

as for the continuity I checked between the black plug slot and dist housing and I do not get 0..
 
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