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Fuel pump problems

3K views 10 replies 7 participants last post by  whynotthinkwhynot 
#1 ·
I'll try and keep this short and sweet.

Car is a 2002 SE/Auto. The car has now sat for ~13 months. Ran perfect when parked. I undid some mods, put it back to stock including swapped the cat, reinstalled EGR accessories, swapped AC compressor, AC line, and installed a new battery. On crank the car turns over, starts, and runs very rough for ~10-20 seconds then dies. After it dies it will not start again. I let the car sit over night, tried it again in the morning and it did the same thing, ran for ~30 seconds and then stalled with the same problem.

This is what i have done to troubleshoot it. I know i have spark. Assuming it may be gas i dumped some fresh gas with some "Start!" and this did not help. I unplugged the fuel rail line and cranked and it didn't spray gas. Doesn't spray gas from line BEFORE the fuel filter either. I made sure to press down on the inertia switch in the kick panel just in case. Fuse is good, i'm not sure about the relay but i don't know how to test that. I do not hear the fuel pump prime when i turn the key on. I don't even recall hearing the fuel pump when it starts but i wasn't really listening either. Also using the cluster i can tell the car is not throwing any DTC.


What can i do to further diagnose this before i drop the tank and replace the pump? I know i need to test the relay. Is there any point in the wiring harness i can connect a 12V source to test the pump? Obviously i cannot reach the connector as it is between the tank and the floorboards. Any help would be greatly appreciated
 
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#4 ·
Find the relay, then find another in the bay that is the same one. Swap them. See if that helps or if the other system controlled by the same relay now doesn't work with the swap. You'll eliminate the relay as a problem. There should be several of the same ones under the hood.

I can get you some relays from the yard if need be...
 
#5 ·
In case the inertia switch is bad for some reason- which is doubtful- unplug it, and use some wire to bridge the 2 points on the connector. That will bypass the inertia switch completely.

The fuel pump module is under the back seat on the passenger side. There's not a whole lot you can do here except check to see that there is 12v on the input side when the key is ON. The fuel pump connects to it on the side that goes through the floor.

Problems with the fuel sender might cause issues, but I'm unsure how to diagnose. I would expect a DTC from that one. I wouldn't expect a DTC from a bad fuel pump, or inertia switch.

Your start problem- runs for up to 30 seconds then dies- seems to me like the fuel system is allowing some fuel to get in the lines, then it when that runs out the engine dies. Since you've opened the lines up to air now- it might not do that again.

Um, for future reference, I don't recommend disconnecting fuel lines, and then cranking the engine to see if fuel comes out. I'm sorry I don't have pics, but I do have a friend who can tell you that the smallest spark you can't see from a bad spark plug wire will ignite that fuel and give you 3rd degree burns quicker than you can figure out how to put the flames out. He can also tell you how someone blasting an ABC extinguisher on you can give you lung problems even if it does stop the flames. Keep that stuff in mind next time you want to test fuel and use the electronic odometer trick to find fuel pressure- look for the reading [FP 111] in kpas. If you need to double check the fuel sensor for whatever reason, then get another under-hood fuel line and cut in a mechanical FP gauge.
 
#7 ·
Let us know how the diagnosis goes so we can continue to help you. You're inspiring me to eventually write a "Safety First" How-To once we get done with some re-arranging. Don't feel bad, safety is now my job at work in an industrial chemical setting, so I think about that stuff a lot. Sometimes those "old fashioned" diagnostic ideas aren't as smart as you'd think. There's no sense in sticking your face up a horses butt to see what it's been eating when you can just wait for it to poop on the ground.
 
#8 ·
The voltage to the pump works like the , the 12 volt hot is hot all the time so if you check the 12v + side it will show good

The Focus fuel pump works off a ground base and the ground is regulated so you would need to check both the + and the - side to confirm you have both at the fuel pump wiring after the fuel pump module

Tom
 
#9 ·
this is what i believe is my issue as well, it will start for a bit then die.

have you had it keep running for any amount of time? i had mine start but stutter while driving(accelerating and when getting on it) then would idle down and die at stops.
 
#11 ·
1turbofocus is right, datalogging would help you figure out if your problem was the same as the OP. You might be better off starting your own thread because even though symptoms are similar- the causes might be different. The first thing you should do is see if you can hear the fuel pump when you turn the key from OFF to ON. If you can, then you're better off diagnosing with another angle more towards checking the coil pack and it's power wiring.
 
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