Starting problem
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New User
Joined: Feb 2009
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From: Deep Gap, NC
Starting problem
Hello, when I have my truck in the "start" position it runs( of course I don't do it long because it's bad for it). But when I let go and it switches back to the "run" position it cuts off. Please help!!! Also I AM getting gas and spark.
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Joined: May 2009
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From: Oregon
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Hi, I'm having the same problems with my 1976 F150 4x4 w/360 2B
In response to fmc400, what should the volts be at coil & ground with key in run position? Any and all reply would be helpful. Thanks,
Hi, I'm having the same problems with my 1976 F150 4x4 w/360 2B
In response to fmc400, what should the volts be at coil & ground with key in run position? Any and all reply would be helpful. Thanks,
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Certified Thread Hijacker
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The voltage at the coil should be between 7-9 volts. Most manuals state 7.9 volts is optimal.
What I will do to test the start and run positions is to disconnect the starter cable from the starter solenoid and then ask my lovely wife to turn the key to "start" and hold and then left off to "run" all the while having my DMM leads hooked up to test.
Josh
What I will do to test the start and run positions is to disconnect the starter cable from the starter solenoid and then ask my lovely wife to turn the key to "start" and hold and then left off to "run" all the while having my DMM leads hooked up to test.
Josh
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MSEE
Joined: Apr 2004
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From: Austin, TX
Depending on what version of Duraspark you have, you may see 7-9 volts, or you might see 12 volts, with the key in RUN. It depends if the coil is grounded or not. If the coil does ground, current flows through the resistive wire, there is a voltage drop across the resistive wire, and you see 7-9 volts at the coil. If the coil does not ground, there is no flow of current through the resistive wire, therefore no drop, so you effectively see the battery voltage which is 12 volts. A '76 might have Duraspark I or II, it's hard for me to say. I believe it's Duraspark II that keeps the coil grounded with the key in RUN regardless of the motor running, so in that case you would see 7-9 volts. But if you have Duraspark I, you might see 12 volts because it ungrounds the coil a few seconds after they key is turned to RUN if the motor isn't actually running.
If you have breaker points (your '76 shouldn't), whether or not the coil is grounded depends where the points rubbing block is resting on the points cam, which would dictate whether the points are open or closed.
If you have breaker points (your '76 shouldn't), whether or not the coil is grounded depends where the points rubbing block is resting on the points cam, which would dictate whether the points are open or closed.
New User
Joined: May 2009
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From: Oregon
No points, pick coil... Stator!! Check coil to ground w/key in the run position and got 6.8 volts. Need to do more checking... From what I have read on the forum, resister wire, brain, stator, key switch?????
Thanks FMC400 and Bullitt390 for your reply... appreciated
Anyone with any thoughts or suggestions, Please chime in.
I live in Oregon and it is raining here now... So it might be a few days befor I get back out to it.
Thanks
Thanks FMC400 and Bullitt390 for your reply... appreciated
Anyone with any thoughts or suggestions, Please chime in.
I live in Oregon and it is raining here now... So it might be a few days befor I get back out to it.
Thanks
Certified Thread Hijacker
Joined: Aug 2001
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Well it's slightly low on voltage, but it does mean you ARE getting voltage to the coil in RUN.
I would test to see if you are getting voltage in RUN to the module which would be the red/blue wire at the connector.
Josh
I would test to see if you are getting voltage in RUN to the module which would be the red/blue wire at the connector.
Josh
MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
Less voltage across the coil primary winding means more of it is dropping across the resistor wire in the dash, which could mean the coil winding resistance is below the specification. Disconnect the coil harness, and measure the resistance between the BATT and TACH terminals; it should be about 1 ohm.
While 6.8 volts is slightly low; it will not prevent the truck from running. Try this test: keep the coil connected, and run a test light from the TACH terminal of the coil to ground (unpainted metal on the engine). Use the key to crank the motor over, and the light should BLINK. Post back with your results.
While 6.8 volts is slightly low; it will not prevent the truck from running. Try this test: keep the coil connected, and run a test light from the TACH terminal of the coil to ground (unpainted metal on the engine). Use the key to crank the motor over, and the light should BLINK. Post back with your results.
MSEE
Joined: Apr 2004
Posts: 10,386
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From: Austin, TX
Good point; in which case I agree to test the module for power in RUN as you have described above. Since the coil is receiving power in RUN, the ignition switch is likely okay. Since the motor can fire in START, it's likely the ignition module is able to run when powered from the WHITE wire. Given this information, my first assumption would be to suspect an internal fault in the module that prevents it from being powered from the RED whire when the key is in RUN.
Ejay - you can also take the module to a parts store and have it tested. The tester is not good at identifying modules that experience intermittent heat-related failures, but it can rule out any permanently damaged modules.
While you're in there, disconnect the distributor connector, and measure the resistance between the PURPLE and ORANGE wires on the distributor-side of the connector. It should read between 400 and 700 ohms. This tests the pickup module in the distributor.
Ejay - you can also take the module to a parts store and have it tested. The tester is not good at identifying modules that experience intermittent heat-related failures, but it can rule out any permanently damaged modules.
While you're in there, disconnect the distributor connector, and measure the resistance between the PURPLE and ORANGE wires on the distributor-side of the connector. It should read between 400 and 700 ohms. This tests the pickup module in the distributor.