This is topic Fuel pump issues.... in forum Tech Talk at Northern California Ford Owners  .


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Posted by NEIGHT (Member # 8741) on :
 
So I finally finished building my fox and now when I'm trying to start it up my fuel pump is not turning on at all. Is there anything I should be checking for? I have a new 255lph fuel pump installed and I changed out the whole motor harness for a new one to avoid electrical problems. I'm sure it's something simple but I'm kinda frustrated at this point because the fuel pump will not turn on at all. I want to check other things before I drop the tank and all that because I have quite some fuel in there which makes it hard for me to do it all myself like I've been doing.
 
Posted by jo_arce02 (Member # 11777) on :
 
inertia switch, and or fuel pump relay???
 
Posted by i (Member # 12534) on :
 
quote:
Originally posted by jo_arce02:
inertia switch, and or fuel pump relay???
+2 Double check the wiring since you're running new wiring. Do you hear your fuel pump on when you try to crank it from the ignition? I'm myself about to get my shit running hopefully my fuel pump turns on the first try.
 
Posted by NEIGHT (Member # 8741) on :
 
quote:
Originally posted by i:
quote:
Originally posted by jo_arce02:
inertia switch, and or fuel pump relay???
+2 Double check the wiring since you're running new wiring. Do you hear your fuel pump on when you try to crank it from the ignition? I'm myself about to get my shit running hopefully my fuel pump turns on the first try.
I've reset the inertia switch and tried starting it after every time I pressed it, no luck. No the pump never turns on no matter if its the second click or I try to crank it'll just crank and crank with no pump action. [Frown] I guess my next step is to follow all the wires thru the car but I was kinda hoping people would know common problems when this happens so I can check that out first.
 
Posted by hurting your feelings (Member # 13641) on :
 
Grab a test light and test for power at the fuel pump harness at the back of the car.
 
Posted by Blind (Member # 3052) on :
 
I don't know the background on the car, but if this was a 4 banger conversion, the fuel pump relay under the drivers seat on my `89 4 banger was just a dummy empty black box, once I swapped in a real relay from the donor car the fuel pump worked.
 
Posted by NEIGHT (Member # 8741) on :
 
quote:
Originally posted by Blind:
I don't know the background on the car, but if this was a 4 banger conversion, the fuel pump relay under the drivers seat on my `89 4 banger was just a dummy empty black box, once I swapped in a real relay from the donor car the fuel pump worked.
No it's not a conversion, I've owned this car for 5 years and drove perfectly fine I just wanted to go a lot faster so I swapped motor and suspension. I'm going to buy a new fuel pump relay today just to see if that maybe fixes it, if not it's only $20 and I'll have a new relay not to worry about later. I hope it's something this simple. When yours didn't have the relay connected the pump never turned on?
 
Posted by Blind (Member # 3052) on :
 
quote:
Originally posted by NEIGHT:
quote:
Originally posted by Blind:
I don't know the background on the car, but if this was a 4 banger conversion, the fuel pump relay under the drivers seat on my `89 4 banger was just a dummy empty black box, once I swapped in a real relay from the donor car the fuel pump worked.
No it's not a conversion, I've owned this car for 5 years and drove perfectly fine I just wanted to go a lot faster so I swapped motor and suspension. I'm going to buy a new fuel pump relay today just to see if that maybe fixes it, if not it's only $20 and I'll have a new relay not to worry about later. I hope it's something this simple. When yours didn't have the relay connected the pump never turned on?
that's pretty much how relay's work. Relay's are $1.50 though, not $20

At the fuel relay junction, you can test for voltage when the key is on to see if you have power to that point.

Then you can test for voltage outside the tank at the tank harness juction before it goes to the top of the tank and connects to the pump to see if you have power there. You can also test for voltage at the cutoff inertia switch by the taillight, and you can test if that switch works by hitting it with a small hammer - you'll see the button pop up.

At any of these points, once you identify what is +12v and ground going to the fuel pump, you can run wires to a 12v battery and test if that will make the pump turn on. It's really a very simple process to test everything.

[ 2016-03-24, 04:44 PM: Message edited by: Blind ]
 
Posted by NEIGHT (Member # 8741) on :
 
Ok I'll do that. Thanks
 
Posted by Martinna (Member # 12493) on :
 
Find the underhood EEC diagnostic connector near your drivers side shock tower and ground pin A to turn on the fuel pump manually --- http://www.supermotors.net/getfile/245234/fullsize/dlc-eeciv.jpg This will also make the green relay under your seat click if you have someone hold it to feel the click.
 
Posted by SIC9250 (Member # 8216) on :
 
quote:
Originally posted by hurting your feelings:
Grab a test light and test for power at the fuel pump harness at the back of the car.
This.1st thing you always do in this situation lol
 
Posted by SLOWSN95 (Member # 8269) on :
 
Trace back the wiring. Start from the back and see if you have power.. if not, go down the line. Process of elimination before you start throwing parts at it. Also, not sure if it applies to your car, but there should be a relay under your driver seat I believe. See if it's clicking over.
 




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