Hello first time posting .I have a 87 150 with a 300 6 . I have power to the coil but not going out to the distributor when i put my test light on the neg side of the coil the light stays on . installed a new coil and ignition switch , a little stumped hope someone can help <Tony

 

Sounds like a faulty TFI module on the distributor.

 

thanks i will give that a try

 

It's most likely the ignition module bolted to the side of the distributor. You will need a special tool to remove it. Check the automotive parts stores to find this tool.

Another possibility is the pickup coil inside the distributor. You need to remove and disassemble the distributor to replace this. I'm betting on the ignition module though.

The coil would have been another possibility, but you already eliminated that.

 

Ok thanks .the truck has been running great just wouldn't start yesterday morn ,does that seem odd ?

 

Odd maybe, but not unusual for the ignition systems of this vintage.

 

This tells you the coil is more than likely good as you have continuity through the coil windings but the NEG side is not being pulsed to ground.

The odds are you have a bad ICM on the side of the distributor but as said above it could also be the PIP sensor inside the distributor.

But before you change out any parts and spend more money do a few checks.
First unplug the EEC computer and see if the spark returns. If it does make sure you have good grounds on the ground pins and power on the power pins of the computer. If you do then more than likely you have a bad computer.

If spark did not return when you unplugged the computer then take the ICM off the distributor and take it to an auto parts store and have it tested. If it tests good then buy a new distributor or a stator and install the stator in your distributor. Do not buy a rebuilt or re-manufactured distributor as you will get a bad one most of the time.
The PIP sensor is mounted on the stator so you have to replace the stator for a bad PIP sensor.

 

Most auto parts stores can test the module for you.