1999 F150 does not start
Asked by Tomasaur Aug 08, 2017 at 07:26 PM about the 1999 Ford F-150 XL 4WD LB
Question type: Maintenance & Repair
My F1 50 used to run fine, but it's been parked for
a while and now will no longer start.
The engine turns over and the battery is strong.
I'm not getting spark at the spark plug although I
am getting power to the coil pack that sits on top of
the engine.
I'm not getting any trouble codes from the code
reader.
Suggestions as to where to go next?
Thank you, Tom
4 Answers
beatupchevy answered 6 years ago
if the coil's getting a signal and there's no spark coming out of it I'd say the coil is bad
Ah yes, I forgot to mention one more diagnostic bit. The connector to the coil has four pins. 1 pin has 12V positive when the key is turned on. The other three pins should each send a 12V pulse to fire the coils. I'm not getting the triggering signal when The engine is turning over. This makes me think that the problem is upstream of the coil, particularly relating to the firing signal. That's where I'm stuck. Sorry for not being clear before.
beatupchevy answered 6 years ago
I know enough auto elec to get by and that's about it , I don't think the signal goes "to" the coil , it's a primary field and a secondary , the build up/collapse of the primary creates the spark in the second one so there's a switch "down stream" from the coil going on and off , thats the ignition module , these signals can be relayed,amplified who knows , the small batt. from a multi tester can burn out the computer and other sensitive circuits , you may get some questions with each answer if this is a learning experience ,a wiring diagram would help,
Thanks! I never really understood what was going on in the coil. This certainly is a learning experience, and I may wind up hiring a pro in the end, but so far it's been interesting...