I have a 1991 F150 that just quit running. I have put on a new coil, distributor cap, rotor & module. I show voltage at the cap from the coil but not out of the cap to the plugs. Could it be the voltage is enough to show up on a meter but not strong enough to jump the gap from rotor to cap? I was told that the condenser has nothing to do with strength of the spark. Is this true? KCF
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check the voltage of the coil ( stamped on the bottom
if it has 7.5 volts then the problem is the run circuit from the ignition switch to the coil or distributor
It turns over and fires on the start circuit as that is straight 12 volts but when you release the key to the run position it goes through a resistance wire or block to drop it to 7.5 volts or the coil will burn out
with the key in the run position connect a multimeter to the coil wire and read the voltage ( if it is not there you have not connected up the circuit properly
if you have a voltage there and it is 12 volts make sure the coil is a straight 12 volt coil
Set the engine to the number one compression,and bring the timing mark to zero on the harmonic balancer.(or just bring the timing on the harmonic to zero). mark to match the plug wires to cap,remove the cap.(if you can remove the cap without removing plug wire) mark the rotor position to the engine using a scribe, mark the rotor to the distributor, mark the distributor to the engine using a scribe,Take the lock down bolt out and pull out distributor. when you reinstall line up all your marking and check timing.
Several things can cause this problem, cracked distributor cap, old ignition rotor. Or if you have coil packs, cracked coil pack, ignition control module, crank position sensor, cam position sensor. Coil pack parts and sensors can be checked by autozone, cap and rotor will have corrosion on the rotor, however a small crack in the distributor cap can be next to impossible to see, replacement is usually best option.
Check pickup ring inside the distributor sounds like the wire is broken and make sure you have power going to ignition module. If you don't go to library and use their all-data services for test procedures for no spark condition. If you have power to ignition module i would say its the pick up coil in distributor. This system is a pretty reliable one. I have seen new modules that where bad so you might have yours tested by your local parts store most of them will test them for free or a small charge.
Good luck I hope this helps get you back running agian
There are 3 possibilities. 1 the coil. 2 the ignition module. 3 the pick up coil. In my experience the ignition module is the most common cause. It is in the distributor held in with 2 screws. The coil and module can be tested at any parts house. Good Luck
I had the same problem with my 85 cj7 this week, I relpaced the ignition control module, plugs, wires, cap, rotor and the the coil; still had no fire to plugs. the problem turned out to be my distributor, replaced it today and she fired right up. Most likely it was the pick up module in the distributor that went bad.