i have a 78 80 hp thunderbolt. last week i was running wide open and it just stopped. got it home and found that there was no spark on #3 and #4 cylinders. i used a timing light to check. it will run but only if the fast idle is all the way open. i checked the stator and it seems to be ok except the resistance readings are about 20% higher that what the manual says. the trigger is brand new, i replaced a month ago because of bad wired. all wires seem to be fine but no spark on 3 and 4. all 4 coils resistance are great, and the plugs and wires are new.could the fact that i have spark on 1 and 2 but not 3 and 4 stear me to a specific part?
Your description makes me think you have ADI distributorless style ignition rather than Thunderbolt with a distributor.
At any rate, you need to test everything all over again and take nothing for granted, and don't assume that because something has been replaced it can't be faulty again.
Alternator Driven Ignition, your engine should have 4 coils. It probably is the stator but heres a simple test for it, just swap the red and red/white and the blue and the blue/white wires at the box and if it's stator the problem, the spark will goto 3&4 cyls. and will stop on 1&2.
Alternator Driven Ignition, your engine should have 4 coils. It probably is the stator but heres a simple test for it, just swap the red and red/white and the blue and the blue/white wires at the box and if it's stator the problem, the spark will goto 3&4 cyls. and will stop on 1&2.
That'll work.... if the fault don't move, it's the switchbox....
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1978 mercury 80 thunderbolt ignition problems
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