88 Ford F150 - Intermittent Ignition
#16
12-01-2016, 06:51 PM
Tuesday 11/29/16... Drove the truck in a semi jerking/vibrating state a 5 mile distance running a errand. Engine died/cut out completely, AAA tow truck carried it home.
Using a spark tester with a 7/16" air gap to test coil... spark was red, very thin, intermittent, weak. Bottom line = coil failed.
Installed new coil = Engine starts in START position. Actually starts better than it ever did, even when new.
I suspect that previously engine would not start in START position as the failing coil couldn't function properly with the starter drawing voltage away from it.
The DC voltage being applied to the coil is a full 12v in the RUN position. Resistance is the same and normal with both coils (new/old)... Suspect the old coil is arcing out to the yoke.
The spark still looks red to me but it is hot and constant, however since the truck now starts promptly in the START position, I'll hold off on replacing the ignition switch UNLESS it acts up once more, at which time I'll have to put it in the shop as I can't get into the necessary position needed to replace it... leastwise I don't think I can.
I don't understand why the spark from the new coil isn't a strong blue.
Thank you all once again for your time and advice... whatever happens, I'll be sure to get back to you.
Using a spark tester with a 7/16" air gap to test coil... spark was red, very thin, intermittent, weak. Bottom line = coil failed.
Installed new coil = Engine starts in START position. Actually starts better than it ever did, even when new.
I suspect that previously engine would not start in START position as the failing coil couldn't function properly with the starter drawing voltage away from it.
The DC voltage being applied to the coil is a full 12v in the RUN position. Resistance is the same and normal with both coils (new/old)... Suspect the old coil is arcing out to the yoke.
The spark still looks red to me but it is hot and constant, however since the truck now starts promptly in the START position, I'll hold off on replacing the ignition switch UNLESS it acts up once more, at which time I'll have to put it in the shop as I can't get into the necessary position needed to replace it... leastwise I don't think I can.
I don't understand why the spark from the new coil isn't a strong blue.
Thank you all once again for your time and advice... whatever happens, I'll be sure to get back to you.
