starts and stalls

[Tools R Us]

:whoops: I missed this part.

... So I tried jumping it from the diagnostic port and it runs fine...

The diagnostic port supplies ground signal to the relay. If it runs on the diagnostic jumper, your problem is in the AFM or wiring to/from it. Possibly a bad ground at the point where the AFM ground is connected.

 

[Straydog]

I'll start looking for the ground.
My diagram looks like that a little, but what I'm trying to say is there is no circuit opening relay in my relay diagram. Like a road map to their location. Thats where my issue is. Its not in the pass. kick panel. Only things there are the Ecm and light reminder. I'm just trying to narrow the search.

 

[Tools R Us]

I'll start looking for the ground.
My diagram looks like that a little, but what I'm trying to say is there is no circuit opening relay in my relay diagram. Like a road map to their location. Thats where my issue is. Its not in the pass. kick panel. Only things there are the Ecm and light reminder. I'm just trying to narrow the search.

I don't know where they hid it on the '87 trucks, but the '85 FSM shows it above the ECU. If it works with the jumper, turn the key on and any noise makers (stereo, fan, etc) off, install one side of the jumper in the check connector, have a helper touch the other end to the other side of the check connector repeatedly. Each time it’s touched you should hear the relay click and the pump run, look, feel around under the dash until you find the clicking box!

If it runs with the check connector jumper in, then the relay and wiring to the check connector are good and it’s not getting the ground signal from the AFM to turn it on. It’s one of a few things, the AFM switch isn’t working. The wire connected to the E1 AFM terminal, isn’t grounded, isn’t making a good connection, is broken. Or the wire between Fc AFM terminal and the check connector has an issue.

You can find the problem and repair it, or just install the check connector jumper and drive.