f-150 no spark at plugs fixed

thanks for all the replies, the truck belongs to my BIL and I was trying to help him get it going, it was getting to me as nothing I tried would increase the spark enough to get it to the plugs, so after some research I found out that a condenser on a conventional ign. system does more than buffer the arch between the points to help prevent tracking of metal across the contacts, to put it in my lay mans terms it also helps force the ign. coil to discharge at high voltage, then the light can on some part of the TFI system has to do the same thing as the coils are basically the same, so even though dist. assy. was a newly rebuilt and I was getting a trigger signal to the coil I replaced the module and it fired up in less than 2 revolutions.

Don't you just love all this electronic stuff?

NOT sure of your analogy between a condenser (which that vehicle doesn't have) and a failed ignition module, but, "what the hey"!

Did you (as I suggested) "Ohm out" the spark plug wires to make sure none are "open" after your "saga" (as they say) of a couple of failed modules?

I had an '87 F-150 with 300-6 and an '88 Mustang with 5.0L HO and BOTH went down within a day of each other with the Thick Film module in the distributor failing. And I thought the Dura-Spark ignition my old '78 F-150 300-6 had was junk!

Thanks for the reply!

I built a TFI tester I don't remember the last time I used it, why because I keep a couple old distributors around now just hook them up and spin the dist by hand and check spark... The same with GM HEI its a quick and simple test. If you are going to keep a ford with this dist keep a look out for a junker you can rob the dist off of any with TFI will work for diagnosing spark issues even one off a 4 cyl. The last one I did I had to rob a original TFI off a junk dist because new aftermarket modules keep failing...

I hope it came with the correct grease (heat sink compound) to mount the module :wink: Heat is a killer.... I never remotely mounted a module ford did in later years remotely mount them now that I think about it I never replaced a remotely mounted TFI module...

A diagnostic nightmare get a hold of one were they put the trigger wheel in upside down.... Maybe that was a dura spark but its a real curve ball...

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You have me a little confused You originally said you installed a rebuilt distributor. Didn't that already have a new module? I know my 1995 F150 has the module attached the distributor.

rebuild dist was installed about a month before because of no trigger signal to the coil then this problem arose, and yes I tested everything, replacing the coil wire with 2 known good ones all ohm about the same, even though the test reading were in spec on the modules and the pip module in the dist was sending a trigger signal to the coil the output of the new coil would sent fire to the dist but wasn't strong enough to fire the spark plugs even with new cap and rotor, after the new tfi module was installed it started right up with the old cap rotor and coil wire, to better explain the condenser used in a breaker points system in relation to the electronic which doesn't have one except for one used as a noise suppressor, take a coil that is use on a points system hook it temporary without a condenser then flash the grd side to a grd and see how much of a discharge you get, then install a condenser on the grd side flash the grd again and see if there isn't a difference in the discharge of the coil, the coil on the tfi system is basically the same except for its outward design, however it works something in the module has the same effect on the output of the coil

Inline spark tester that uses a light... I do not like them but that does not mean I do not use them they do have some value. The value is it does show the event is happening and in some cases like yours once you get use them you can see strong/weak firing events such as in your case. New aftermarket module failers are not uncommon in most cases you will see the tester light be bright and intermittently go dim when the engine stalls. That is if you are lucky enoufh to be able to duplicate the event in the shop...

I would be looking for a deal on a OEM are stock up on used OEM modules they are not that hard to plug and play it sure beats hours of diagnostic time..

One more thang its worth the price to know you have the fight heat sink compound...

Google: Arctic Silver 5

GBS, you have learned something about a condenser I have been telling people for years, but it is amazing how many do not believe it. They were told a long time ago a condenser only kept the points from burning and just do not believe it has an additional purpose.