Bone stock 87 GT car ran and drove fine last fall when I put it away for the winter. I replaced the battery this spring. Fuel pump does not prime when I turn key to On. When I jumper the fuel pump at the test port, the pump runs, and the car fires right up. I do not want to drive the car with the test port jumpered, and ignore the problem.
What I find unusual is that when I check the wiring at the fuel pump relay (with the relay removed) the Tan/Light Green wire has continuity to ground with the key on, and the engine not cranking. It seems that the ECM is sending the ground signal as long as the key is on, even if the engine is not cranking or running. I have removed the 60 pin ecm connector, and the ground signal at the fuel pump relay connector goes away, so I believe that the Tan/Lt Green wire is ok. This leads me to believe that the trouble is within the ecm. It is the original Ford ecm, with seal still attached.
I suspect the relay is fried, at this point, but I am concerned that just replacing the relay, and not diagnosing the constant ground at pin 22 will just fry the next relay.
I have read MANY threads on here about fuel pump and relay issues, but have not found any threads relating to constant ground signal at pin 22 of ecm. I'm new to Stangnet, I'm not new to Mustangs.
All suggestions appreciated.
What I find unusual is that when I check the wiring at the fuel pump relay (with the relay removed) the Tan/Light Green wire has continuity to ground with the key on, and the engine not cranking. It seems that the ECM is sending the ground signal as long as the key is on, even if the engine is not cranking or running. I have removed the 60 pin ecm connector, and the ground signal at the fuel pump relay connector goes away, so I believe that the Tan/Lt Green wire is ok. This leads me to believe that the trouble is within the ecm. It is the original Ford ecm, with seal still attached.
I suspect the relay is fried, at this point, but I am concerned that just replacing the relay, and not diagnosing the constant ground at pin 22 will just fry the next relay.
I have read MANY threads on here about fuel pump and relay issues, but have not found any threads relating to constant ground signal at pin 22 of ecm. I'm new to Stangnet, I'm not new to Mustangs.
All suggestions appreciated.