Hello everybody,
I recently purchased a 1989 Mustang GT, and it has a check engine light. I don't have any history on the car, so I'm really starting at step one. I followed jrichker's post here on the process for checking the CEL codes but unfortunately the CEL light never flashes. It just remains solid.
This morning after some more Googling I discovered post #8 on this thread (https://www.stangnet.com/mustang-forums/threads/check-engine-light-on-after-eec-iv-switch.772570/). I removed my ECU and opened it up to discover that this trace was less than optimal. I installed a bodge wire which seems to have fixed something because now when I attempt to perform the code pull the vehicle recycles the fuel pump and relays after I turn the key on. This was not the case before.
I attempted to leave the negative battery terminal unhooked for approximately 30-60 minutes multiple times now to clear the CEL. However, this also didn't work. I'm not sure if there is another procedure.
This is my first OBD1 Ford; I'm usually running around in an OBD1 Honda so I'm more familiar with their acronyms and verbiage. So I'm not sure which sensors will trigger a CEL like this. I apologize if I'm doing something completely wrong and I appreciate everyones time and advice. Thank you in advance.
I have recorded a video since I believe it will further help troubleshoot the issue. You can view it here
I recently purchased a 1989 Mustang GT, and it has a check engine light. I don't have any history on the car, so I'm really starting at step one. I followed jrichker's post here on the process for checking the CEL codes but unfortunately the CEL light never flashes. It just remains solid.
This morning after some more Googling I discovered post #8 on this thread (https://www.stangnet.com/mustang-forums/threads/check-engine-light-on-after-eec-iv-switch.772570/). I removed my ECU and opened it up to discover that this trace was less than optimal. I installed a bodge wire which seems to have fixed something because now when I attempt to perform the code pull the vehicle recycles the fuel pump and relays after I turn the key on. This was not the case before.
I attempted to leave the negative battery terminal unhooked for approximately 30-60 minutes multiple times now to clear the CEL. However, this also didn't work. I'm not sure if there is another procedure.
This is my first OBD1 Ford; I'm usually running around in an OBD1 Honda so I'm more familiar with their acronyms and verbiage. So I'm not sure which sensors will trigger a CEL like this. I apologize if I'm doing something completely wrong and I appreciate everyones time and advice. Thank you in advance.
I have recorded a video since I believe it will further help troubleshoot the issue. You can view it here
Last edited: