I have a 1986 F150 302 EFI. The timing light is dark when my ignition key is at start. When I let it go to run, the engine is winding down but my coil sends a few spark signals. Sometimes the engine catches and turns over, sometimes not.

I've replaced the Hall Sensor and checked out the TFI module. The module has similar resistance readings compared to a new module. I have battery voltage at the "run" pin on the TFI connector. I do get a slight voltage drop at the "start" pin on the connector as compared to the battery voltage. Is this acceptable?)

When the engine catches and turns over, the spark is solid and timing is spot-on. Does this prove my module is okay or can it be defective?

Any other troubleshooting?

 

I would take the module to a shop and have it tested. I work at O'Reillys, and though I'm not sure if all the locations have it, ours has a pretty decent tester by Borg Warner. Funny enough, of three brand new TFI modules I tested, the only one that tested good was the Motorcraft one I ordered for myself. Two of Borg Warner's own part tested bad, along with a cheapy 'Master Pro' one.

 

Pull the codes.

 

I happen to have 3 modules from different stores...and prices (El Cheapo $18, $33, and expensive $86).

Guess you get what you pay for. I'll try them to troubleshoot...unfortunately, there isn't anyone around here that can test the modules.