weird ignition problem
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Freshman User
Joined: Dec 2006
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I put a 10 gauge wire from the + side of the battery to the + (top) terminal of the coil and tried to start it. just like before, it started just fine, but died when the switch returned to "run"
New User
Joined: Jan 2008
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It shouldn't be doing that.
It should stay running.
What happens is:
The Igntion switch is powered all thr time from the battery .......with the key in start..12v power runs to coil at the same time power goes to the starter solenoid.
once the key moves to RUN..... Power is cut to the solenoid and then resisted power from the switch runs to the coil energizing the ignition system thru the switch RUN position.
as per the illustration I posted above
With power to the coil coming directly from the battery.... by-passing the resistance wire from the switch....the engine should stay running.
My first thought is to try another Ign. switch ......
How many volts are at the coil + terminal with the key in RUN?
It should be more than 8.5v.
The ignition system requires 8.5v to operate.
It should stay running.
What happens is:
The Igntion switch is powered all thr time from the battery .......with the key in start..12v power runs to coil at the same time power goes to the starter solenoid.
once the key moves to RUN..... Power is cut to the solenoid and then resisted power from the switch runs to the coil energizing the ignition system thru the switch RUN position.
as per the illustration I posted above
With power to the coil coming directly from the battery.... by-passing the resistance wire from the switch....the engine should stay running.
My first thought is to try another Ign. switch ......
How many volts are at the coil + terminal with the key in RUN?
It should be more than 8.5v.
The ignition system requires 8.5v to operate.
New User
Joined: Jan 2008
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Likes: 24
That may be the problem.
That switch is for a late 78 and newer.
What is the number stamped on the aluminium casing.
D8TB- 11572-AA ?
What are the last 6 digits of your truck VIN# ?
Here's the list of switches for 1976
MOTORCRAFT SW-944 IGNITION SWITCH
Note: built after serial g90,001
http://www.rockauto.com/catalog/x,ca...,parttype,4516
It may look like this.
http://info.rockauto.com/SMP/SMPDetail3.html?US85.html
That switch is for a late 78 and newer.
What is the number stamped on the aluminium casing.
D8TB- 11572-AA ?
What are the last 6 digits of your truck VIN# ?
Here's the list of switches for 1976
MOTORCRAFT SW-944 IGNITION SWITCH
Note: built after serial g90,001
http://www.rockauto.com/catalog/x,ca...,parttype,4516
It may look like this.
http://info.rockauto.com/SMP/SMPDetail3.html?US85.html
Last edited by Mil1ion; Dec 10, 2006 at 06:55 PM.
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Thread Starter
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Freshman User
Joined: Dec 2006
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Hey Dennis, that's the number on the original switch which worked just fine for so long. I would have to pull the new switch to check its number, but it looks identical to the original. The last 6 digits of the ID number written on the inspection sticker looks like C66559. I don't know where the VIN number plate is on this thing. I thought it would be on the dash like most other vehicles, but it's not.
New User
Joined: Jan 2008
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The ignition switch with 9 pins like the prove out shown above is for the switch shown on the right.
This switch was started in use later in the 78 year.
The earlier 78's used the switch on the left which was a carry over from 1977 ....this switch is a 6 pin.
This switch was started in use later in the 78 year.
The earlier 78's used the switch on the left which was a carry over from 1977 ....this switch is a 6 pin.
Thread Starter
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Freshman User
Joined: Dec 2006
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Dennis, I feel like a damn fool. The inspection sticker says it's a '76, but everything else I just looked at to find a VIN number says it's a '78. I'm sure that makes a difference in what we are talking about. The number on the ignition harness is D8UB-14489-AB (or ...88-AB, it's hard to read). There are 11 slots in the fuse box with a 12th that is not being used, not even wired.
Postmaster
Joined: Aug 2005
Posts: 2,760
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From: Gadsden Purchase
Originally Posted by Torque1st
Have you tested the ignition module, magnetic pickup and the power wires (red and white) feeding the module? Testing modules is free at most parts stores.
Anyway... I swear Sailor I had the exact same symtoms you are having with my '75 F150 back in about '78. I put a new Blue Streak module in it then and it ain't acted like that since.
I figure I screwed up the original module because I couldn't afford a battery even tho the battery was bad i was jumping it etc and the alernator you know can make some really high voltage when the battery isn't there to "draw" it back.
So what kinda monkey business you done with the electrical lately? ...just before it started acting up? ;)
It acts as if the resistor to reduce the voltage to the coil while running and is bypassed during starter cranking is bad or at least intermittent right? The module is still kinda working just needs more voltage is my guess. Mine was getting full voltage just that it -wanted- more after it went half-bad?
Alvin in AZ
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Re-check the 1st (6) in the inspection sticker.
C66559.
78's would start with CA,CC,CE,CG,CJ
I suspect yours is CG.
You thru me off with 1976 in the initial post.
Nice
Now I have to get Eric to remove 10 of my posts
C66559.
78's would start with CA,CC,CE,CG,CJ
I suspect yours is CG.
You thru me off with 1976 in the initial post.
Nice
Now I have to get Eric to remove 10 of my posts