Fuel pump short


sd359

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Rocky Mount, Va
Vehicle Year
1994
Make / Model
Ford
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4.0
Transmission
Manual
I have a late year 1994 Ranger 4wd 4.0l extended cab. Form time to time when I turn the ignition switch on you don't hear the fuel pump run. Normally a few turns of the key and it starts and everything is fine. Today I tried to start engine just spun, after about 10 tries of not cranking I popped the hood. The ignition was still in the on position when I pulled the hood latch I heard the fuel pump come on and it cranked right up. It seems I have a loose connection or short under the hood. Any ideas where to start?
 


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RonD

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canada
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The fuel pump relay in the engine fuse box, pull it out and check connections, pins and slots
Also Fuel pump fuse, same thing check for corrosion

The computer activates the FP relay by grounding it
You can do that manually on a 1994 and older Ranger to test the system

Go here: https://therangerstation.com/tech_library/OBD_I.shtml

2nd drawing shows Fuel Pump slot in the OBD connector
This connector is next to the engine fuse box on the firewall side
GROUND that slot with jumper wire
When you turn on the key, FP relay should Close and FP should start
Pull out the jumper and FP relay should Open, repeat as you see fit to see if its activating each time its grounded, key on
 

engine

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Ashe Co NC
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2002
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I'm not sure this will help, but I had intermittent starting problems for a long time. A fuel pump, a replacement under warranty, and then a fuel pump relay, each time seemed to fix the problem. But then it recurred again, and again. I used up all four of my AAA tows in the process and the fancy dealer diagnostic did not reveal any problem and I drove it home again. When it happened again, I was blessed with a home visit from our local Ford service manager who by shifting the relays started it again. He said if it happens again, I can shift the relays or beat on the fuse box. If that doesn't help, the fuse box needs to be replaced. And it happened again. It is not a Ford replaceable part but our dealer was able to find a salvage. Splicing the wires of the harness seemed to be a big job to me but it was, done, in maybe someone's spare time at the dealer. and all seems to be well now. Our dealer's motto is "We want to make friends for life". And they do!

This probably would not have happened in the big city and I would have lost my Ranger!
 

sd359

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Rocky Mount, Va
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1994
Make / Model
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Engine Size
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Transmission
Manual
I had the problem again and checked all the connections on the driverside fenderwell just made sure they were all connected. The problem had not happened since. I have started the truck probably 10 times since. I just replaced the intake gasket about 2 weeks ago. I thought maybe the wires weren't connected good but I had this problem before that but not very often. As of right now everything seems good. But who knows when it will happen again. When it does I'll check what you guys have suggested. I might replace the FP relay just to be on safe side. Thanks for your responses. The members here are so knowledgable about rangers it is a great resource.
 


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