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I have 2004 ford Escape 3.0. At 62K the fuel pump went out, just stopped pumping. I replaced it with a Motorcraft pump and all was well for 2 months, then that pump quit, so I replaced it again. Now it’s 2 months later and the 3rd pump has quit. The question is, is this just a bad coincidence or is there another reason for all these failures that I should be looking for? My fuses, relays and wiring seem to be ok and the car has been babied since new, including being garaged and never off road. Any help would be appreciated, thanks.
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You need to perform a voltage drop test on the circuits as follows:
Fuel System Troubleshooting and Electrical ChecksThe ProblemFuel system repairs are often performed without proper diagnosis, leading to unneeded parts and the inconvenience of doing a complex repair that does not fix the vehicle problem.
The SolutionBasic fuel system troubleshooting and diagnosis can be accomplished with a digital voltmeter and some knowledge of vehicle electrical systems. This bulletin provides some guidelines for system electrical tests.
System Components to Check FirstIf the vehicle will not start, check the following:I’m with Jacob on the voltage drop test but I was also wondering how you determined that the pumps were bad, did you check to see if they had power and ground at the connector going to them? If not the pumps might not have been the problem all along. Also if you have a lot of sedement in the tank this will also cause premature failure. Lastly make sure you follow the manufacturers recommendations when doing the install, there might be an issue there that you might not be aware of.
Do you have any way of checking to see how much current the pump is drawing? Excessive current draw could be leading to premature pump failures.
I did voltage test on the on the pump circuit and did have voltage, I don’t remember the reading now. I didn’t know about the voltage drop test and I’m not sure how to access the pins on the pump with the connectors together. The tank is very clean inside so sediment is not an issue. Here’s a new wrinkle, the pump started working again today, so I’m thinking you are on the right track, it’s not the pump at all. I’ve tried to check all the connections and grounds and used a scan tool and have no codes set. I’m going to check some more tomorrow but I don’t have near the expertise that you guys do and may have to bite the bullet and take it to the dealer. Anyway thanks a lot for the help!
I just use sewing T-Pins to probe connectors when doing voltage tests. Jacob pasted all the info you needed to do the tests. Just take your time and im sure you will find the issues.
Electrical issues are always the most intimidating at first 🙂
I don’t have a meter to measure current, but that sounds like a good thought too. Or is it possible that they pump is running too much? Anyway I’m going to try the drop test if I can access the wires. Thanks again!
It sounds like you might have an intermittent break in the wiring or connections leading down to the pump. When you replaced the previous pumps maybe the moving of the wires temporarily restored your connection? Next time the pump stops maybe you do a resistance check with a DVM to see if you see the coil resistance of the pump through the wire harness from the start.
I did another voltage test at the pump harness and came up with a steady 6.65 volts. I also tried to do the voltage drop test but couldn’t establish continuity through the connector, I’ll try again tomorrow. As far as a break in a wire, I’ve looked at that, but it’s not obvious if that is the problem .Since it’s running again, maybe I should start it and then mess with the wiring to see if it dies.
6.65? Was the battery dead or weak? Let me see something… Nope! This car does not have an external pump driver and should be battery voltage of whatever the battery storage is minus the load itself.
You should have battery voltage meaning if you check the battery and it has 12.4 your pump voltage should be the same or close to it. 1/2 a volt less is the start of a problem somewhere.
Make sure you run a test lead directly from the battery to the tester (make sure the lead is good as well) so if you are checking the pos side of the pump circuit then you need to run your lead from the negative side of the battery post thus checking the pos voltage and so on for the ground side.Note: take a reading from the battery alone with the pump energized and note that voltage reading as it is, and when you check the pump circuit it should be close to the battery voltage.
I do this test all the time without doing the voltage drop thing but I have the trained eye to determine if a voltage drop should be performed.
I have commonly seen after market alarms with immobilizer systems cause this very issue as they normally interrupt the fuel pump circuit and now the immobilizer alarm box now becomes part of the circuit.(They suck)
What is the name and model of that alarm? (That alarm isn’t doing a better job than the factory system does) I posted a diagram above.
Thanks much to jacobnbr1 for the wiring diagram, that makes things a little easier. If I’m reading it right, I am on the right wires with the black and pink black. So I think my 6.65 volt reading is correct. I was originally thinking that voltage could be variable through the PCM. I need to do the drop test and other tests jacobnbr1 suggested and see what I come up with. Answering some of the back posts, I have 12.5 volts on the battery and have switched relays to known good ones. Thanks for sticking with me guys!
No I already checked for remote mounted driver, that car don’t have that system.
Yes you are reading it right pnk/blk and blk.
Look at that diagram and look at all the voltage stops along the way and where ever there is a component there is a potential for a voltage drop starting at the fuse box feed to the fuse.
It only requires battery source voltage from the output of the fuse so if you confirm the 6.65 volts at the pump, change over to the ground wire side and run the test lead from battery positive to the fuel pump ground and if it reads 12.4 (or whatever source voltage is) then the ground is perfect but the problem is in the positive side circuit of the vehicle harness.
You can move on from there and test the voltage drop at the output of the inertia switch, relay, fuse and if you have 6.65 there, then the problem is in between that component and the pump connector.
Let me know if you don’t understand and I will break it down for you.
I mean lets make an example…
The battery for the available source for what it is of say 12.5 with the fuel pump energized (fuel pump prime, key on engine off) so we leave the battery with 12.5 and go to fuse f16 utilizing a protection of 20 amps(and still having 12.5) following that wire to the fuel pump relay and exiting (still having 12.5) then on to the s138 splice(still having 12.5) then passing through the crash safety feature inertia switch exiting with (6.65) and continuing to the pump connector (with only 6.65). In this example the inertia switch is causing the voltage drop because we should transfer the full 12.5 to the pump with the pump energized(fuel pump prime, key on engine off) but can’t because say the windshield leaks water into the cabin and down the A piller into the switch causing corrosion and a bad connection. (true story on an f series truck)
If you really have 6.65V on the pump that means you are losing almost 6V somewhere. Is there a relay that turn this pump on? If so it could have pitted contacts.
This is a four wire harness going into the pump, now I’m wondering if I’m on the right two wires? I’ve been checking the black and red w/black stripe. With the key on and the connector unplugged there is 6.65 volts across the two wires and it’s steady. Still haven’t done the drop test. There is a dealer installed Ford Vehicle Security System alarm on this escape, the one with the little red light under the dash. If I knew how to disable it I would, it has done funny things in the past. I didn’t know that it could shut down the fuel pump. An intermittent problem with the alarm would make sense. Thanks again for all the help, I’ll keep trying…
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