Fuel Pump (new) Wiring

MitchFromPEI · January 28, 2010

I ordered a fuel pump through my local parts store and got a spectra premium, that is why it was cheap I guess. But the connector won't fit so you have to wire your own. The colour seems to match up, so I wired it for colour, purple to purple, black to black grey to grey, etc and it still won't go. How do I know if i'm wiring it right?

MitchFromPEI · January 28, 2010

Update, I tested the new pump with a battery pack on two leads and the pump fired. So I put my wire with the voltage on it to the pump, and the other wire I tried on all other 3 leads with no pump going. I'm only getting 5V at the wire from the truck. My battery is run down, but I should see 12v at that purple wire? Keep in mind I know the old pump is bad, becuase I had to bump the tank to get it going before it just quit all together. Also, there is no fuel pump fuse marked on my fuse layout, under the hood or inside the truck. WHich one is it?

Where is the fuel pump grounding? I checked the purple wire to the frame and still just 5 V. Man i'm confused here as to why my ignition won't fire this pump. Maybe I am just wiring it wrong, but without a wiring diagram for the connector. I'm lost.

The way I have it hook up, colour for colour, and wire guage for wire guage. My fuel guage is reading the correct amount of fuel. I just can't see to get 12v to the pump, only 5 is coming in on the purple wire.

I'll take some pictures tonite when the camera gets home.

I have 5V on the purple wire coming from the 4 wire loom, to where I had to wire in the new harness. But when I put the wires together as per colours, I lose the volt reading on the purple wire to ground.....

Nytemare · January 29, 2010

Update, I tested the new pump with a battery pack on two leads and the pump fired. So I put my wire with the voltage on it to the pump, and the other wire I tried on all other 3 leads with no pump going. I'm only getting 5V at the wire from the truck. My battery is run down, but I should see 12v at that purple wire? Keep in mind I know the old pump is bad, becuase I had to bump the tank to get it going before it just quit all together. Also, there is no fuel pump fuse marked on my fuse layout, under the hood or inside the truck. WHich one is it?

Where is the fuel pump grounding? I checked the purple wire to the frame and still just 5 V. Man i'm confused here as to why my ignition won't fire this pump. Maybe I am just wiring it wrong, but without a wiring diagram for the connector. I'm lost.

The way I have it hook up, colour for colour, and wire guage for wire guage. My fuel guage is reading the correct amount of fuel. I just can't see to get 12v to the pump, only 5 is coming in on the purple wire.

I'll take some pictures tonite when the camera gets home.

I have 5V on the purple wire coming from the 4 wire loom, to where I had to wire in the new harness. But when I put the wires together as per colours, I lose the volt reading on the purple wire to ground.....

Sounds like you have it wired properly....usually we just chop the connector off the old pump and wire that in.

The fuse for the fuel pump is ECM B under the hood, its a 20A fuse. And the Relay is F/PUMP

MitchFromPEI · January 29, 2010

Update, I tested the new pump with a battery pack on two leads and the pump fired. So I put my wire with the voltage on it to the pump, and the other wire I tried on all other 3 leads with no pump going. I'm only getting 5V at the wire from the truck. My battery is run down, but I should see 12v at that purple wire? Keep in mind I know the old pump is bad, becuase I had to bump the tank to get it going before it just quit all together. Also, there is no fuel pump fuse marked on my fuse layout, under the hood or inside the truck. WHich one is it?

Where is the fuel pump grounding? I checked the purple wire to the frame and still just 5 V. Man i'm confused here as to why my ignition won't fire this pump. Maybe I am just wiring it wrong, but without a wiring diagram for the connector. I'm lost.

The way I have it hook up, colour for colour, and wire guage for wire guage. My fuel guage is reading the correct amount of fuel. I just can't see to get 12v to the pump, only 5 is coming in on the purple wire.

I'll take some pictures tonite when the camera gets home.

I have 5V on the purple wire coming from the 4 wire loom, to where I had to wire in the new harness. But when I put the wires together as per colours, I lose the volt reading on the purple wire to ground.....

Sounds like you have it wired properly....usually we just chop the connector off the old pump and wire that in.

The fuse for the fuel pump is ECM B under the hood, its a 20A fuse. And the Relay is F/PUMP

shouldnt I have more than 5v at the pump? If I can manually start the pump with my battery pack, then the pump should be fine right. As for that fuel pump test wire under the hood, you say its in that connector connected by the wheel? pull it apart and send 12v down the red wire?

Nytemare · January 29, 2010

Update, I tested the new pump with a battery pack on two leads and the pump fired. So I put my wire with the voltage on it to the pump, and the other wire I tried on all other 3 leads with no pump going. I'm only getting 5V at the wire from the truck. My battery is run down, but I should see 12v at that purple wire? Keep in mind I know the old pump is bad, becuase I had to bump the tank to get it going before it just quit all together. Also, there is no fuel pump fuse marked on my fuse layout, under the hood or inside the truck. WHich one is it?

Where is the fuel pump grounding? I checked the purple wire to the frame and still just 5 V. Man i'm confused here as to why my ignition won't fire this pump. Maybe I am just wiring it wrong, but without a wiring diagram for the connector. I'm lost.

The way I have it hook up, colour for colour, and wire guage for wire guage. My fuel guage is reading the correct amount of fuel. I just can't see to get 12v to the pump, only 5 is coming in on the purple wire.

I'll take some pictures tonite when the camera gets home.

I have 5V on the purple wire coming from the 4 wire loom, to where I had to wire in the new harness. But when I put the wires together as per colours, I lose the volt reading on the purple wire to ground.....

Sounds like you have it wired properly....usually we just chop the connector off the old pump and wire that in.

The fuse for the fuel pump is ECM B under the hood, its a 20A fuse. And the Relay is F/PUMP

shouldnt I have more than 5v at the pump? If I can manually start the pump with my battery pack, then the pump should be fine right. As for that fuel pump test wire under the hood, you say its in that connector connected by the wheel? pull it apart and send 12v down the red wire?

No...its not connected to anything...its just a bypass lead, there is nothing connected to it other than the fuel pump.....If I had a picture I'd show you.

The 5V you are getting at the pump is a signal....not a drive voltage. That's the reference voltage that tells the pump to start, and also the voltage used to register how much fuel in in the tank.

You probably popped the fuse when the pump finally went.

Check the ECM B fuse.

You will only get a 12V reading when the truck is running and when the key is turned to the run position for 3 seconds...that's the prime feature...other than that you will get a 5V signal to the pump....at least that's how its supposed to work.

MitchFromPEI · January 29, 2010

Well of course we would have, to have a 20cm storm today. Went out and snapped pictures quickly.

Here is what I know, The purple wire from the loom to the pump is the 12v supply from the relay. And is a smaller gauge. The black larger gauge from the loom is is the fuel level sending unit signal. The gray from the loom is fuel level sending unit ground, and is also larger guage. And the final black with white stripe, smaller gauge is the ground.

As for the new pump connector, I know the larger guage black and grey, if 12v is directly applied from my battery pack, it will fire the pump. Any ideas? I had color for color before and all I would get is a gas guage reading with no pump turning on. ECM B fuse is good. Relay has been tried from another relay the same from the fuse box, there is like 4 of the same kind.... Which is strange, because the purpler wire from the loom, is smaller than the wires i'm applying 12v too, to get the pump to fire separately from the truck circuit....

MitchFromPEI · January 29, 2010

Still storm here, but got a chance to sneak out. I put my voltage tester on the relay (lifted it up a hair). I got 11v on the passenger side of the relay, and 5v on the drive side. I'll check with someone turning the key over the weekend. As I hooked my meter to the purple and ground, turned the key off and on a few times, and got no voltage change on the purple wire. (for the 3seconds). Just a solid 5V. Even with the key back. Even without the pump hooked up, I should have 12v on that purple wire for a few priming seconds and when the engine turns... Right?

Nytemare · January 29, 2010

Still storm here, but got a chance to sneak out. I put my voltage tester on the relay (lifted it up a hair). I got 11v on the passenger side of the relay, and 5v on the drive side. I'll check with someone turning the key over the weekend. As I hooked my meter to the purple and ground, turned the key off and on a few times, and got no voltage change on the purple wire. (for the 3seconds). Just a solid 5V. Even with the key back. Even without the pump hooked up, I should have 12v on that purple wire for a few priming seconds and when the engine turns... Right?

If the purple is the 12V supply to the pump you should have 12V on it when the key is put in the run position for about that first 3 seconds....the wurrrr sound that comes from the pump just before you start the truck.

place your meter on the Blk/wht wire and measure resistance to ground (chassis). I bet you have a break in that ground wire.

MitchFromPEI · January 30, 2010

Yikes it's nasty out! Snuck out again. I got continuity between the black/white and the frame. (meter rings out, 1ohm) But not continuity to frame from the other wire that is marked as a ground in my book..... Should that be grounded to the frame? IE is that the problem? I took the wires coming from the pump connector (off the pump) and I can get continuity from the larger black wire and grey wire. (that is the wires I apply 12v manually from a seperate source). And I can ring out the other smaller pair between each other. So, i'm thinking. Maybe that purple wire isn't the wire that sends down 12v, and just has a constant 5v for fuel guage...... Let me know what you think, i'll do some more testing when the weather lets up. *UPDATE* I looked @ the schematics in the back of my haynes manual. Click on the link and then the magnify glass at the top right, and click and hold mouse down to drag image around. http://picasaweb.google.ca/MitchTheGreat/D...533684508974050

Shouldn't that 12v wire be the gray then?

MitchFromPEI · January 30, 2010

*UPDATE* sorry to over flood this thread with information. But it could be handy to someone else who has the same problem. Got the fiance to turn the key forward and got 12v from the gray wire to the frame!! I was on the wrong wire (the haynes book in the fuel pump section say's it is the purple) But the schematic straightened that out. So now I know that second ground, is not grounded. It should always be grounded correct. The book shows two wires in that connector, ground for 12v and ground for fuel guage. I can just run a ground do that wire to the frame?

MitchFromPEI · January 30, 2010

Well in between white conditions letting up, I managed to get it going. You were right, I was missing a ground. Also, my book has the colors wrong in the fuel pump chapter. I had it wired correctly, just the thicker black wire (the ground for the 12v pump circuit) wasn't grounded. I must have broke it when I lifted the bed, or maybe it was on with one of the rear tail lights ground screw that was removed. I just drilled a tek screw into a cross section of the frame and ran a ground too it. Thanks for all your help.

Any tips for getting that black plastic holder off the fuel filter and fuel lines? I frigged around with it for a bit, I got the bolt off. But I can't get the lines free from the clamps.

Nytemare · January 31, 2010

Well in between white conditions letting up, I managed to get it going. You were right, I was missing a ground. Also, my book has the colors wrong in the fuel pump chapter. I had it wired correctly, just the thicker black wire (the ground for the 12v pump circuit) wasn't grounded. I must have broke it when I lifted the bed, or maybe it was on with one of the rear tail lights ground screw that was removed. I just drilled a tek screw into a cross section of the frame and ran a ground too it. Thanks for all your help.

Any tips for getting that black plastic holder off the fuel filter and fuel lines? I frigged around with it for a bit, I got the bolt off. But I can't get the lines free from the clamps.

I assume you mean the ones that hold the lines to the frame??

Never used it again...always go get a new clamp. I use the ones that are metal on the outside and have rubber on the inside...they're used for wiring in houses and buildings. The name of them escapes me right now.

I dont like disturbing those plastic clips as they usually remove a part of the line with them due to rust you guys get out on the east coast....(I am originally from Newfoundland).