99 Gt Blown Fuel Pump Fuse #14

Discussion in 'SN95 4.6L Mustang Tech' started by Sam Kosorl, Nov 20, 2013.

  1. Sup guys, I just got this 99 GT from my brother. Its been running great. Until recently..I left a friends house at night and was not paying attention..I drove the car in a small ditch in front of the house. Impacted the front passenger side wheel and most likely the rear passenger side too. Car drove for about 1 block and then sputter. If I gave it anymore then a 1/4 gas. Came to a stop and idle was low and rough, then it turned off. After an hour figuring what had happen..I found the fuel pump fuse (20amp mini) to be blown. replace and car fires up, drove for about several miles and it blows again. pulled over replaced drove on the freeway for about 5 miles and it blows again, but I just kept on driving it since I was close to home. It did not turn off but was idling low and rough as before. I got home and suspect that maybe the alarm wiring that was in there before I got the car may have caused it. So I got the alarm removed and all wires repaired. Drove the car the next day for about 20miles miles and I felt the stumble again. Check fuel pump fuse and it is blown again. Why would the car still stay on and drive if the fuel pump fuse is blown, and what do you guys think is causing the fuse to blow. Bumps are not causing it, as I had drove the car over some bumpy roads before hitting the free way. Engine harness has been checked, O2 harness checked. Battery ground terminal was loose after the impact, but has since been tighten properly. Inertia switch checked. Most people have issue with blown fuse the sec they turn the engine over, I'm having the fuse blown while driving and I can continue to drive so as I dont give it too much gas, also smells, like running rich or something when this fuse blows.
  2. Normally the motor should run for only a few seconds should the fuel pump fuse (F1.14) blow. The fact that the car continues to run tells me either the fuse is not the fuel pump fuse or there is a short somewhere that's powering the fuel pump from a different source.

    Since the impact damage (right front fender) is were the CCRM is located, my vote is either internal damage to the CCRM or wiring damage around the CCRM. Consider starting with a visual inspection.
  3. wmburns, What fuse do you think is blowing then? Its a mini 20 amp fuse on the top left. Fuse cover shows its F1.14. I can reproduce the symptoms by removing the fuse and driving the car. If the fuse is removed prior to starting the engine, the engine will not start. Yesterday I drove it to work and back home with no incident. Today I drove it to work with no incident. My friend who does electrical work said he checked the CCRM for any wire damage and did not find anything. This is driving me nuts. I do know that the issue only started after the car ran into the ditch. I guess we can double check the CCRM location again.
  4. At the CCRM pin #5 (DG/YE), measure the key off voltage. Post. Should be zero. Now measure the key on voltage. Should be battery voltage.

    Now pull fuse F1.14. Voltage should go to zero.

    It might be easier to perform these tests at the trunk mounted IFS switch as the IFS switch is the first down stream component on the 1999-2004 SOHC GT.