HELLPPP!! FUEL PUMP WILL NOT WORK

Will Rey

New Member
Joined
Aug 12, 2020
Messages
34
Reaction score
1
Location
North Carolina
Hey guys I’ve literally tried everything to get my mustang to run. So I’ll fill you guys in to see if I missed anything. I bought a 1996 Mustang 3.8 with a 4.6L swap. The day I went to buy the car the guy dropped it on his jack trying to put the tires back on and dented the oil pan. But I still insisted to ask to run the car even tho it prob was hitting the crank. The car ran for about 3 seconds and then I turned it off. Then I let the car sit for about 2 weeks until I had money. I got the parts to replace the pan and did it and when I went to crank the car, the car wouldn’t turn over. So I took off the fuel line and started the car and little to no fuel came out. So I suspected the pump was bad so I replaced the pump and still the same issue. I attached the negative lead to the negative side of the battery that was connected to jumper cables and checked the fuse box and I’m getting 12v and I checked the plug to the fuel pump and I’m getting the proper readings. I checked the side of the passenger door for the fuel pump relay and I saw it was missing it so I bought a relay and plugged it in thinking that was the issue but it didn’t solve it. Then I read somewhere that I should check the FPDM but I looked where it is suppose to be and it’s not there so I think my car doesn’t have one. My last bet is to replace the CCRM but I thought I would hop onto the threads to see if I missed anything. Also I took it to a shop and they also told me the fuel pump was bad and that’s why I replaced it but I’m guessing that wasn’t the issue so if anyone has any input that can give me that would help :))) I’ll also upload videos and pics tm for references
 

96blak54

Legend
Joined
Feb 21, 2011
Messages
7,950
Reaction score
1,250
Location
Ky
That inertia switch is somewhere! Go fish!

My 96 is located trunk tail light wall to the left. Youll need to remove some wall interior, possible trunk latch beauty panel. Dig in and find it!

Be sure to report back if it was the inertia switch
 

RAU03MACH

Well-Known Member
Joined
Apr 23, 2019
Messages
3,079
Reaction score
2,504
Location
NEW MEXICO
First you should not disconnect the fuel Line to check for fuel
Thats what a fuel psi gage is for testing
Like @96blak54 said check the trunk for your inertia switch
Pink with blue stripe positive wire
 

96blak54

Legend
Joined
Feb 21, 2011
Messages
7,950
Reaction score
1,250
Location
Ky
Might want to double check power flowing thru the switch. Then maybe apply power straight to the pump just to see if it will in fact run.
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
27,669
Reaction score
3,589
Location
Evansville Indiana

apsmith49921

Active Member
Joined
Aug 5, 2020
Messages
695
Reaction score
564
Use a car battery with leads attached to the terminals.

Edit: just realized it's possible the fuel pump doesn't run off a full 12v. Can someone chime in?

My suggestion is to start at the plug that plugs into the pump. Check for voltage and make your way backwards until you find power.

Sent from my SM-G955U using Tapatalk
 
Last edited:

Benni614

Member
Joined
Jul 6, 2017
Messages
215
Reaction score
149
Location
Delaware
I already checked the inertia switch and reset it and still nothing. I forgot to mention that.
Ok. Did u check signal to the inertia switch
Fuse relay. Can u manually prime the pump if so the u know wires you tested are good up to the component you bypassed

Sent from my SM-N975U using Tapatalk
 

lwarrior1016

Mr. Secondary Timing Chain
Staff
Joined
Sep 22, 2014
Messages
6,187
Reaction score
1,238
Location
South Mississippi
You said you checked the wires at the pump and got a proper reading? What exactly did you check? If you have voltage and ground at the pump connector but the pump doesn’t run, then the pump is bad or has a bad connection inside the tank.
 

ttocs

Post Whore
Joined
Oct 9, 2009
Messages
27,669
Reaction score
3,589
Location
Evansville Indiana
Ok. Did u check signal to the inertia switch
Fuse relay. Can u manually prime the pump if so the u know wires you tested are good up to the component you bypassed

Sent from my SM-N975U using Tapatalk
this is easy to do there should be 12v on both wires. If the switch was either bad or had a bad connection it would do this
 

Will Rey

New Member
Joined
Aug 12, 2020
Messages
34
Reaction score
1
Location
North Carolina
So here the updated the first picture is the reading from the fuse and the video is when I put the negative lead and positive lead into the fuse it gives me a mV reading that goes up to 400 mV then drops and goes back up. Then I checked the plug into the fuel pump in the next two videos. One prong gives a mV reading that goes up then back down and repeats. One prong gives me a .4 V reading. One prong gives me a 11 V reading and the last prong gives me a 6.7 V reading. I don’t know how to check the volts coming out the inertia switch. Another thing to mention I don’t have a FPDM where it should be. I’ll attract a photo. All that is plug into there is my keyless entry in the back. There’s on wire that is suppose to be plug into something but I can’t find what plugs into it anywhere online.
 

Attachments

  • B0202C43-AA05-4B73-BAFD-A99DA2ED3660.jpeg
    B0202C43-AA05-4B73-BAFD-A99DA2ED3660.jpeg
    318.1 KB · Views: 9
  • 6E7D4B98-9C45-476F-A475-EED144247F3F.jpeg
    6E7D4B98-9C45-476F-A475-EED144247F3F.jpeg
    300.8 KB · Views: 9
  • D863AA8D-FC06-4409-BD98-1887BE8E802C.png
    D863AA8D-FC06-4409-BD98-1887BE8E802C.png
    1.7 MB · Views: 9
  • 885946FA-7315-49CE-9BCF-2F0D28C09CF0.png
    885946FA-7315-49CE-9BCF-2F0D28C09CF0.png
    1.8 MB · Views: 9
  • BFC226B9-9FEC-415B-B371-C502A14DFB5F.png
    BFC226B9-9FEC-415B-B371-C502A14DFB5F.png
    1.8 MB · Views: 9
  • A8D413F0-2120-4325-8756-8F0914F23C3B.png
    A8D413F0-2120-4325-8756-8F0914F23C3B.png
    1.8 MB · Views: 9

RAU03MACH

Well-Known Member
Joined
Apr 23, 2019
Messages
3,079
Reaction score
2,504
Location
NEW MEXICO
I have 1 question
When you removed the oil pan that you stated
Was there a wire harness under the front oil pan
 

bigmike636

New Member
Joined
Jun 7, 2020
Messages
35
Reaction score
32
I’m not sure why you would check the fuse by inserting the negative lead and the positive lead into the fuse. If I were you, I’d keep the negative lead on the negative battery terminal. Then I would place the positive lead on one side of the top of the fuse, where the metal extends above the fuse. Then place that same positive lead on top of the other side of the fuse. If you have 12 volt power on both, it would appear that the fuse is good. If you actually pull the fuse, you can test it by placing the VOM into the resistance mode. Then you would take one lead and place it on one leg of the fuse and place the other lead and place it on the other leg of the fuse. If the fuse is good, your resistance reading should read close zero ohms of resistance. If however the fuse is bad, you would see a high resistance value.


Sent from my iPhone using Tapatalk
 

RAU03MACH

Well-Known Member
Joined
Apr 23, 2019
Messages
3,079
Reaction score
2,504
Location
NEW MEXICO
What I'm thinking is he might have created a similar problem
With wire harness at the bottom of the oil pan
All those wires are at the side by the battery and fuse box
 

bigmike636

New Member
Joined
Jun 7, 2020
Messages
35
Reaction score
32
I know that I may be comparing apples to kumquats here, but my daughter had an issue with her Mercury Mariner (3.0 Liter V6) not starting. When I checked the connector to the fuel pump for voltage, I thought I had 12.6 volts to it. But before I replaced the pump, I checked to make sure that she had a good ground to the pump connection and I found that she didn’t. I had 12.6 volts power, but no ground. It wound up being the crappy aftermarket fuel pump driver module that I replaced on it three weeks prior. After I replaced it with a new Motorcraft one, the pump fired right up.


Sent from my iPhone using Tapatalk
 

Latest posts

Forum statistics

Threads
74,876
Messages
1,452,435
Members
13,561
Latest member
ffpletch

Members online

Top