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MPI Fuse Continually Blowing

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1990EclipseGSX

20+ Year Contributor
317
16
Apr 7, 2003
Angel Fire, New Mexico
OK, so 2 days ago I installed a 3" GM MAF and MAF Translater, and yesterday I was cruising around at around 40mph waiting for my fuel trims to adjust to the translater settings. I went to turn around to head back home, and when I pulled off of the road my car died. I figured that the changes I made to the idle on the MAF-T were too severe and the car died, so I went to restart the car but it would not start. I have a TMO with a security code and the C/E light was not flashing to bypass it so I thought it had to be the CAPS on the ECU, but they are fine. Then I started checking fuses and found that the MPI fusible link was blown. I replaced it, turned the key to the on position and it promptly blew again and the MPI relay clicked off. I searched for everything that I thought could be causing it, replaced the fuse once more and it blew again. When I try to start the car with it blown, the fuel pump turns on and the MPI relay clicks afterwards, so I don't think it is anything dealing with the fuel pump. I also just replaced the o2 sensor so I don't think that could be causing the fuse to blow either. Any ideas as to why my MPI fuse keeps blowing?
Thanks,
Chris
 
Well, I went out the next day and towed my car back home, and the ride was a little bit bumpy from the rope losing and gaining tension going down hills. When I got the car home, we disconnected the MAF-T, O2 Sensor, MPI relay, and the fuel pump harness. I put in a new fusible link and it didn't blow. I then plugged each sensor back in one at a time from the front of the car to the back, and it didn't blow all of the way through the MPI relay. At this time I figured it had to be the wiring to my 255 so I pulled the pump and redid the connections. I put the pump back in, connected the harness and the car fired right up. The next day I took the car out for a drive to see if the problem was truly fixed, and the car ran great and pulled hard for about 15 minutes, then after a 3rd gear pull the fusible link blew again. I put in a new fuse, disconnected the MAFT, etc. again, and the fuse blew when the MPI relay was plugged back in. I left the car for the night, came back the next day, and started following the wiring harness back from the pump because I figured the short had to be in the wiring after the MPI relay since the fuse blew blew when the relay was plugged in. I pulled out the rear interior panels and found no sign of a short anywhere. I pushed and fiddled with every little relay and connection behind the panels. I decided I would put another fuse back in just to see if anything had changed and magically it didn't blow. I carefully drove the car home, and then rewired my fuel pump w/ 10g wire to see if that would fix the problem. The next day I took the car out for a spin again to see if my problem was fixed and the MPI fuse blew about 1000 yards down the road. I rechecked the harness from the pump back and again found no signs of a short. I also fidgeted with all of the relays again. I pulled out my coil to see if any of the wires from my MSD install were shorting, and they were all fine too. I put in another fuse and it blew as soon as I turned the key to the on position. I think that somehow slight movements are causing the short to come and go. Could the MPI relay or fuse block be causing the short? Please help, I am stumped at this point... What would cause a fusible link to blow randomly?
Thanks,
Chris
 
I went through everything and found a few wires that quite possibly could have been causing my problem and I covered them all with tape. I think I have it fixed this time, at least I hope.......
 
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