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Kenny Z.
Kenny Z., Ford Senior Master Tech
Category: Ford
Satisfied Customers: 5235
Experience:  Auto Trans, Drivability and Electrical Specialist
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Replaced non serviceable rely on 2004 expedition and fuel pump

Customer Question

replaced non serviceable rely on 2004 expedition and fuel pump is still not running
JA: Thanks. Can you give me any more details about your issue?
Customer: 2004 5.4 expedition would not start checked fuse box and rely that is part of circuit board was blown replaced and fuel is not working still
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Submitted: 7 months ago.
Category: Ford
Expert:  Kenny Z. replied 7 months ago.
Hello, my name is***** and thanks for your question.Do you have power at the inertia switch on the green/yellow while cranking the engine?
Customer: replied 7 months ago.
no it does not
Expert:  Kenny Z. replied 7 months ago.
Are you familiar with the CJB connector for the internal fuel pump relay?
Customer: replied 7 months ago.
probably but I I'm very inclined
I did replace the303 relay on circuit board it was burned
Expert:  Kenny Z. replied 7 months ago.
So you disassembled the CJB and replaced the fuel pump relay? Very impressive. There is a four wire connector on the CJB, close to the large connector that has the sliding lock. Diagram of it in the link below. First make sure fuse 9 has power on both sides in the run and start positions. If OK then disconnect that 4 wire connector and jumper between the green/yellow and the blue wires and see if the engine starts. Let me know...https://www.dropbox.com/s/jcvtbn818yjzoz1/pump.pdf?dl=0
Customer: replied 7 months ago.
fuel pump did not start
I do have fuel pump out of tank and connected
Expert:  Kenny Z. replied 7 months ago.
You might have more than one issue, jump green/yellow to any power source just to verify pump runs
Expert:  Kenny Z. replied 7 months ago.
Assuming fuse 9 good with power on both sides also
Customer: replied 7 months ago.
jumped green and yellow directly to battery and pump worked
Customer: replied 7 months ago.
could it be another bad relay some where
the test I just did tells me with g harness okay. must be in the cjb
Customer: replied 7 months ago.
still
Expert:  Kenny Z. replied 7 months ago.
Ok that's good, the blue isn't actually involved in relay operation, just used it as a power source, probably needs to be plugged in to be hot then. the coil side hot of the relay and the load side hot are both buss fed internally so hard to verify power there. You can but you would need to get on the terminals directly where that 4 pin plug seats in the CJB. Two of those pins should be hot in run and start. One comes off fuse 9 buss and one comes off PCM relay buss. If Ok then this leaves the ground pin. The PCM grounds this pin which energizes the coil and closes the contacts. You know the load side to the pump is good. If you have power on two of those terminals in that cavity then all that is left is ground from the PCM. Assuming the CJB is reassembled correctly. You can reassemble all plugs then apply ground to the pin in the link below and see if the pump runs. Its in a different connector. I will be offline until later this evening.https://www.dropbox.com/s/rqzerdvzxp2muh7/RELAYGROUND.pdf?dl=0
Customer: replied 7 months ago.
ok thx
Customer: replied 7 months ago.
just one more thing if this works what do I do then?
Customer: replied 7 months ago.
fyi didn't work
Expert:  Kenny Z. replied 7 months ago.
If you have power on 2 of the pins and grounding the other pin in the other connector I gave you does not run the pump then the problem is still in the CJB fuel pump relay.
Customer: replied 7 months ago.
okay I manually hooked up the battery to the fuel pump and it is running and pumping gas.
everything is plugged in to the cjb tried to start but no luck
Customer: replied 7 months ago.
I grounded the #12 pin and ran power to the fuel pump and it started and ran
Expert:  Kenny Z. replied 7 months ago.
Ok that really doesn't confirm what the failure is. Running power to the pump eliminated the entire relay control system. I just wanted to know if grounding that pin caused the pump to run without adding any power to the pump.
Customer: replied 7 months ago.
it did not run with ground hooked up
Expert:  Kenny Z. replied 7 months ago.
You never mentioned if there was power on both sides of fuse #9 in the run and crank positions.Fuse 9 is one of the buss feeds for the relay, The other is off the PCM relay. The PCM relay also feeds buss fuses 32,33,34. So if fuse 9 has power on both sides run and start then that feed to the relay is good. If fuses 32,33,34 are good run and start then the other feed is good. You substituted your own ground from the PCM. That is all that is needed for the relay to close and run the pump. So to sum up if all the above is good then the issue is still in the CJB. Either an assembly issue, further damage to one of the busses, or the relay not clocked right on the board.
Customer: replied 7 months ago.
I think I'm just going to replace the cjb because I think the circuit board might be bad
Expert:  Kenny Z. replied 7 months ago.
It could very well be.
Expert:  Kenny Z. replied 7 months ago.
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