Aarrgggghhhhhh!! Duraspark lll problem
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Joined: May 2003
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From: San Francisco Bay Area
Aarrgggghhhhhh!! Duraspark lll problem
My 83 Bronco 351 has a crank trigger ignition system. When #1 is at TDC, and the damper pointer is at TDC, where should the crank trigger be?.
On my setup the trigger point is about 10-15 degrees of rotation past the sensor.
To me this looks like the system is told to fire the ignition about that much early, and then the Duraspark lll computer figures out when the actual event will take place.
There is no way to advance or retard timing by moving the dist.
I am fighting a runnability bug where there is slow, poor accelleration,low power, heavy missing at medium power demand. Every ignition component including the dura lll computer has been changed.
It isn't a fuel delivery problem.
The engine is in good mechanical shape with 145-160# per cylinder, and the cam is timed to the zero mark.
This occurred out of the blue about 10,000 mile after a complete rebuild.
Any ideas?
ZARTT(No Email Addresses In Posts!)
On my setup the trigger point is about 10-15 degrees of rotation past the sensor.
To me this looks like the system is told to fire the ignition about that much early, and then the Duraspark lll computer figures out when the actual event will take place.
There is no way to advance or retard timing by moving the dist.
I am fighting a runnability bug where there is slow, poor accelleration,low power, heavy missing at medium power demand. Every ignition component including the dura lll computer has been changed.
It isn't a fuel delivery problem.
The engine is in good mechanical shape with 145-160# per cylinder, and the cam is timed to the zero mark.
This occurred out of the blue about 10,000 mile after a complete rebuild.
Any ideas?
ZARTT(No Email Addresses In Posts!)
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Joined: Aug 2000
Posts: 1,984
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Aarrgggghhhhhh!! Duraspark lll problem
Zartt, welcome to FTE!
Do you have the TFI module type that is attached to the distributor? If so, that would be the first suspect, but you've probably already changed it......what color is it, black or gray?
What about the SPOUT connector? Make sure it's getting a good connnection.
Do you have a MAP (manifold absolute pressure) sensor mounted on the firewall? This sensor affects the timing advance. try unpluging it and see if it changes anything.
I think you're correct in that the crank trigger should give 10-15 degrees of advance. It also sounds like an ignition advance problem.......
Do you have the TFI module type that is attached to the distributor? If so, that would be the first suspect, but you've probably already changed it......what color is it, black or gray?
What about the SPOUT connector? Make sure it's getting a good connnection.
Do you have a MAP (manifold absolute pressure) sensor mounted on the firewall? This sensor affects the timing advance. try unpluging it and see if it changes anything.
I think you're correct in that the crank trigger should give 10-15 degrees of advance. It also sounds like an ignition advance problem.......
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