Fuel 99 Cobra Svt Cranks Fine But Wont Start

Discussion in 'SN95 4.6L Mustang Tech' started by Spiderwolf, Oct 4, 2012.

  1. I have a 99 Cobra SVT. The car was running fine. Pulled it in garage and it sat for a few weeks. Went to start it, it just cranks but wont start. I have no fuel View attachment 142993 pressure at the rail (used a pressure gauge) and there is no sound of pump running when the key is turned on. I checked the fuel pump View attachment 142994 fuse under the hood and its good. I also checked the inertia switch in the trunk. Its got to be some kind of relay or the fuel pump, but Im not sure what my next step would be.

    Is there a relay I need to check? Or, do I need to check for power at the pump. If so, how do I go about doing it. I was a mechanic for 20 years but got out of the business in the late 80`s and never really messed around with fuel injection too much as it just was not to popular at the time. But Im pretty handy with a wrench and a test light so if someone could give me some direction on what to check out I would appreciate it. Thanks
  2. First, have you looked at all of the fuses?


    Test for +12 volts at the trunk IFS switch with the key on. If no voltage, the problem is a blown fuse, bad CCRM, bad ignition switch, or wiring fault.

    If there is voltage, the problem needs more research. Possible bad FPDM, fuel pump, PCM problem or wiring fault.

    A full set of manuals may go a long way to help you to understand fuel injecting. If interested in getting a set for yourself I maybe able to help. PM if interested.

    Crank with no start check list;
  3. The only fuse found labeled fuel pump was under the hood. I checked it and its good. If there are other fuel pump fuses I dont know where they would be.

    I dont have a working meter but did use a test light at the inertia switch and the light comes on when the key is on when plugeed into either side of the wires which shows there is voltage going through the switch. Something I read in the forum said that if there is voltage through the inertia switch than the CCRM is good and that the problem most likely is a bad fuel pump.
  4. There is a round connector located near the center of the gas tank. Look up from under the rear bumper. This offers an easy location to isolate the fuel pump. The wires to the fuel pump are RD/BK and BN/PK. Use a probe and send 12 volts directly to the fuel pump.

    If the fuel pump does not run, this confirms the diagnosis.

    If the fuel pump runs, the problem is in the FPDM, PCM, or wiring (based upon reported symptoms).
  5. The only place I know to get 12 volts is from the battery. Do I need to run a positive and negative wire from the front of the car all the way to both those wires, one to the RD/BK and one to the BN/PK? I suppose I could just remove the battery and carry it back there but Id still need to make some wires as I dont have anything to do that with. One end of the wires would have to be a clip to attatch to the battery and the other end small enough, like a probe, to touch the pins in the connector right?
  6. On another note the wires going to the fuel pump are not the right color according to you and other other threads I have seen. On one end of the connector, there is a RD/BLK and a BN/PK, but on the other end going to the pump there is only a BN/PK. There is no RD/BK. Putting the connector back together and seeing where the RD/BK goes through the connector, the wire on the other side is just Black.
  7. I'm afraid to get the high level of detail that you need would require your own set of wiring diagrams. This will give pictures of the connector faces, pin numbers and wiring colors.

    As for were to get plus/minus 12 volts for testing there are a couple of options.
    1. Run a wire jumper from the battery.
    2. Since the voltage at the IFS switch has been confirmed, run the jumper from there.
    3. use another battery (your car or another).
    4. use a battery charger. Note, this option will not work if the battery charger as plus/minus reversal protection.
    FWIIW, if using the car's battery, the ground does not have to all the way back to the battery negative. Use a known good ground in the trunk area.
  8. Ok, I pulled the battery, set it a safe distance from the tank. I built some test leads that on one end clip onto the battery terminal and the other end are probes from a bad meter. I confirmed with a borrowed meter I had twelve volts at the probe ends and applied them to the wires BB/RD and BN/PK goint to the pump and nothing happened. I reversed the test leads and tried again. Still nothing. Im guessing at this point that confirms I have a bad fuel pump.

    I had to drop this tank half full of gas so I jacked the tank back up a bit and removed the bolts holding the fuel pump in place and placed a hose in there and am siphoning the gas into two gas containers I have to make pushing the tank back in place after installing the pump a bit easier.

    Looks like Im going to have to find a new pump next week. Should I just go to Ford and pick one up or is there a better alternative out there that is bolt in. I dont want to have to do any modifying.