How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site. Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask Ron Your Own Question
Ron, ASE Certified Technician
Category: Ford
Satisfied Customers: 23821
Experience:  23 years with Ford specializing in drivability and electrical and AC. Ford certs and ASE Certs
Type Your Ford Question Here...
Ron is online now
A new question is answered every 9 seconds

I have an 02 E150 4.2L. No power to fuel pump. If you jumper

Customer Question

I have an 02 E150 4.2L. No power to fuel pump. If you jumper it fuel pump will run but van does not start. Died going down highway like I shut the key off.
Submitted: 1 month ago.
Category: Ford
Expert:  Jared D replied 1 month ago.

Good morning,

Have you checked to see if the inertia switch has been triggered yet? It's located behind the passenger side front kick panel.

Customer: replied 1 month ago.
switch is down.
Expert:  Jared D replied 1 month ago.

Do you have a multimeter to do some electrical testing?

1. Monitor the Dark Green/Yellow (DG/YL) wire at Powertrain Control Module (PCM) pin 40 when the ignition switch is cycled to the Run position. The circuit should indicate battery voltage for 1-2 seconds when the PCM activates the fuel pump relay for the 1-2 second prime of the fuel pump.

2. After 1-2 seconds of reading battery voltage, the DG/YL wire should drop to a reading of close to 0 volts after the PCM releases the fuel pump relay from activation.

3. Watch the circuit while cranking and with the engine running. Again the circuit should indicate battery or charging system voltage when the engine is cranking/running.

4. If the engine does not start due to the lack of fuel pressure, and the voltage on the DG/YL wire doesn't drop below a reading of 5.0 volts unless the ignition switch is turned off, it suggests that the circuit from the fuel pump relay to the inertia switch is open, the inertia switch has tripped, the Pink/Black (PK/BK) wire is open between the inertia switch and the fuel pump, the fuel pump is defective, or the Black (BK) wire which supplies ground to the fuel pump is open.

Customer: replied 1 month ago.
No power to fuel pump. No 2 sec. Prime.
When I turn the key on it blows #8 fuse under the dash.
Expert:  Jared D replied 1 month ago.

You may need to run through a few fuses testing:

If you remove the fuel pump relay does the fuse blow?

If you unplug the MAF (mass airflow sensor) does it blow?

Expert:  Jared D replied 1 month ago.

If you remove fuse 17 in the under hood box does it blow?

Customer: replied 1 month ago.
A wiring diagram would help so I know what's on the #8 fuse circuit.
Customer: replied 1 month ago.
There is no fuse in the #17 position under the dash.
Customer: replied 1 month ago.
How do I know which one is 17 in the under hood box?
Expert:  Jared D replied 1 month ago.

Here is the diagram for the whole fuel control system:

Customer: replied 1 month ago.
if I remove #17 maxi fuse 30amp under the hood #8 under dash still blows when I turn key on.
Expert:  Jared D replied 1 month ago.

So it's not a problem with the fuel pump or pump wiring.

What about if you remove the PCM relay?

Customer: replied 1 month ago.
I just tried that ,#8 still blows at key on.
Customer: replied 1 month ago.
When you pull pcm relay,and turn the key on #8 fuse blows.
Expert:  Jared D replied 1 month ago.

So that means the problem is between the #8 fuse, and the under hood fuse box.

Expert:  Jared D replied 1 month ago.

Pull the #8 fuse and check for resistance to ground. Most like you will find low resistance to ground on one of the terminals.

Customer: replied 1 month ago.
No, it was a shorted wire conning off the coil pack. Short to ground. Thanks anyway.
Expert:  Jared D replied 1 month ago.

Ok cool. Glad you got it sorted out. The coil shouldn't be on the fuse #8 circuit, but maybe we're talking about two different fuses or maybe my diagram is wrong.