ignition switch problem?
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Senior User
Joined: Mar 2010
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From: western ks
ignition switch problem?
I have a 79 with 400 and when I go to start it , I turn the key to start and it cranks fine, however it wont fire and run untill I ease up on the key till its almost back to the run position. It has gotten worse over the last year till its getting really hard to find that sweet spot on the switch that will let it fire and run. Now its about flooded befor I can hit just that right spot. I have put in 3 different key switches and 2 coils. Anybody run into this and know the fix or at least where else to look.
Lead Driver
Joined: Nov 2006
Posts: 5,217
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From: Pa.
I have a 79 with 400 and when I go to start it , I turn the key to start and it cranks fine, however it wont fire and run untill I ease up on the key till its almost back to the run position. It has gotten worse over the last year till its getting really hard to find that sweet spot on the switch that will let it fire and run. Now its about flooded befor I can hit just that right spot. I have put in 3 different key switches and 2 coils. Anybody run into this and know the fix or at least where else to look.
MSEE
Joined: Apr 2004
Posts: 10,386
Likes: 35
From: Austin, TX
Remove the RED with BLUE stripe wire from the 'S' post of the solenoid so that you can hold the key in START without turning the starter. Measure the voltage at the positive terminal of the coil while you hold the key in START, and report your results.
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Joined: Nov 2007
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From: Denver Metro Area, CO
The DuraSpark II module has two power sources - one in START (I believe the white wire) and one in RUN (I believe the red wire). The module retards the ignition timing a few degrees in START, making a hot engine easier to start.
Might get out your multimeter and check for power at those wires (under the hood, at the module) in the respective key positions.
Typical wiring diagram:
Might get out your multimeter and check for power at those wires (under the hood, at the module) in the respective key positions.
Typical wiring diagram:
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Senior User
Joined: Mar 2010
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From: western ks
I tested voltage today. I had 6.6 volts to the hot side of the coil with key in run position and 6.5 to 6.6 with key in crank position. I then ran a jumper from the battery to the hot side of the coil and checked to make sure I had 12 volts there, and it did the same thing ,it tries to start just before the key releases from crank to run position.
Put on a used ign module that I had in the shop and made no difference.....
Put on a used ign module that I had in the shop and made no difference.....
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