I have a 92 F150 with a 302. The truck was running real rough when I pulled it in the garage. It hasn't started since. I pulled a plug and discovered the spark is hardly there. I changed the plugs, cap rotor, wires, coil and module....Same!

Can a pickup coil caused this? This is the only thing left besides the computer right?

 

A failing pickup coil can indeed cause a weak or non-existant spark.

Bad grounds can also cause a weak spark. Check the battery post, frame connection, engine block, and the small post on the radiator support right in front of the battery.

If the pickup coil is weak, it may work with some TFI modules and not others. It may work with good grounds but not bad grounds.

The computer has little to do with spark prior to engine start. The TFI generates spark on its own, by feeding back the PIP signal. To be certain, remove the SPOUT jumper and evaluate the spark quality. This prevents the computer from doing anything to the spark.

As long as you are getting at least some spark, you should at least hear a pop or fart from the engine as you try to crank it. I should think it would start, even with a weak spark. It might not run well, but it should run.

One of the other jobs of the pickup coil and TFI is to send the PIP signal to the computer. This is how the computer knows the engine is running, and how fast it is running. If the computer does not get the PIP signal, it will not fire the injectors, nor will it keep the fuel pump running.

You can test this with a well tuned ear. Turn the key from off to on. Listen for the whine of the fuel pump. It should run for 2 seconds, then shut off. Once you know what it sounds like, try cranking the engine. JUST as you release the key, and all that racket from the starter ceases, you should again hear the whine of the fuel pump for about 1 second. If the computer is not engaging the fuel pump during crank, it is because it is not receiving the PIP signal from the ignition module (or that the grounds are too messed up for it to resolve a valid signal).

If there is no PIP to the computer, the injectors will not be opened, and the engine will crank and crank without a pop. Try cranking with a little starting fluid sprayed into the throttle body. That weak spark plus a little ether should reward you with a "pop" from the engine or even a few seconds of running. This would tend to confirm the lack of a PIP signal.

 

Very good information....thank you!
The engine will pop every so often. Although it will not run if I spray fuel directly into the intake. The fuel pump will run for the two seconds when the key is turned on. I will try to listen for it after a start attempt. I will check all the ground connections that you mentioned. Are there any other ground connections that are critical. This truck is stored out doors the majority of the time (Ohio) and you can imagine the weather it has to endore. If it is a bad ground it wouldn't surprise me. Forgive me but.. what is a Spout Jumper?

Thank you again!

 

The spout jumper is the small gray jumper plug in the harness near the TFI module on/near the driver fenderwell. It is about 1/2 inch x 1/2 inch x 1/4 inch. You remove this jumper in order to set the static ignition timing without interfering "help" from the computer.