Another no spark conundrum...

[Kody165]

So...87 with a 2.9 liter....it's now my dad's truck. He was driving home one night and it just died....no sputter, just cut out like the key turned off.... We've about flipped the truck just searching for a problem....New ignition coil, cap and rotor, wires.... it needed the tune up regardless.....we have spark at the coil but none after the distributer...I swear it's like it's just eating the spark.... The coil has 12 volts, getting it's switching signal, etc.....could it be the TFI not sending an accurate timing signal? We have great fuel pressure and it turns over. The dizzy is also spinning so the timing chain is still in 1 piece btw. Tried unplugging the SPOUT still no avail.....

 

[bronco2fan]

If you've never replaced the TFI, that's probably your best bet. They can be tested too. But chances are if it's that old it needs replaced.

 

[Kody165]

Yea...I'm fairly certain it's the original....I'll give that a shot Monday or so

 

[RonD]

Wait a minute..............if coil is sparking(on it's own) then all that's between the coil's spark and the spark plugs are the cap, rotor and spark plug wires.

TFI module reads the Hall effect sensor in the distributor, TFI module then grounds and ungrounds the Coil to spark it at correct time, very simple system.....when it works.

There is also a START and RUN power source for the Coil/TFI system
When using the starter motor battery power comes from a different place than when engine is running.
But that wouldn't explain engine dying while running

 

[Kody165]

It literally just did on him a week or so ago and it hasn't started since... it's seriously as if the cap and rotor aren't connecting...but they are...that's why that sensor being had makes sense. ..it may be hesitating to send a signal at the right time, only sparking when the rotor is between points

 

[Kody165]

Sorry for the long wait... my neck of the woods in Colorado hasn't been too conducive to outdoors work....After installing the new tfi module, getting the timing right and all that, it runs like a top...thanks for your help!

 

[RonD]

Good work

Thanks for the update