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Discussion Starter #1
Hey guys and gals, 1993 VR-4 here. I had my fuel pump started sounding like it was pumping gravel then quit. I bought the Walbro 255 pump and hardwire kit from 3SX because I read the 255 would do ok with stock fuel system(and it was only like $25 more than a Denso off of Rock Auto). I am installing a new line from the hat to hard lines so I cut the line behind the rubber jump line to get it out. My question is on the hardwire relay. I have included a screenshot of the 3SX wiring instructions. They seemed to not quite match up to the relay though. The black relay wire had an eye terminal on it and everything else had tube terminals. The instructions say to ground the white wire with the eye terminal, but it had a tube terminal. I cut the terminals off and used my own spades so I can switch if necessary. Can someone please check my wiring, please? Also, what do I do with the red relay wire? The 3SI thread link says to ignore it.

Last question, should I cut the hard line from pump to hat and replace with the rubber line and clamps that came with the pump? I have a flare/double flare kit if I need to cut the hard line.
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Keep'n 'em spooled
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Forgetting for a minute what connectors came already supplied on the relay wires, I think you need to at least switch the black and blue relay wires.
You would think there would be a common wiring color code for 5 conductor relays, but I did a Google search and the results were all over the place.
Common sense tells us the small relay wires (white and black) are for the coil and the thicker wires (yellow, blue and red) are for the contacts. DC relays usually work connected with either polarity, but some have a built in diode to protect the upstream circuit that powers it, specifically to reduce arcing on contacts from a coil's inductive load. So it's best to connect it properly.
Do you have a multimeter?
Also look very closely at the relay, most are marked in some way identifying the connections. Try removing the relay from the socket with the wires coming out, it could be on the bottom of the relay.
When I Googled I did see that for many wiring diagrams that the black wire was ground, which make sense since it was supplied with a ring terminal. So I recommend:
Relay Black - connect to ground (stud on the fuel hat)
Relay White - connect to black w/blue strip wire from the OEM Fuel Harness Connector
Relay Yellow - connect to new red wire from the battery
Relay Blue - connect to black w/blue strip wire to the fuel hat/fuel pump
Relay Red - not used, but must be insulated to prevent shorting out

If you have a multimeter, you can easily check the contact wiring from the relay - the yellow, blue and red wires, to check what I said above.
If you don't have a multimeter, and the above doesn't work let me know. I can tell you how to use what's there to troubleshoot and identify the correct relay wiring.

Let us know how it works out. Like I said if the relay does NOT have an internal protective diode, then it would work with the white and black wire switched, so the instructions would be correct. I would like to give 3SX feedback to update/correct their instructions in any event, since they don't match the hardware as they supplied it to you.

On your question about the metal fuel line - yes you need to cut off the end of the existing line so the hose will fit over the piece coming down from the fuel hat.
 

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Discussion Starter #3
Thanks Turbo. Hopefully I'll have a regular work load tomorrow and work on it. I have a multimeter but am a novice with it. I will keep you posted when I get a minute to work on it.
 

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I don't think I'd trust those small push-on connectors for this. They're probably rated for 10 amps, maybe 15 max.
Given how many hot-wire kits have burnt up their 30a fuse holders you're gonna want something more skookum. They're probably fine for the coil circuit but once you get it all together and are sure about the wiring you should consider going back to butt-splice connectors on the pump wires.
 

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skookum - strong, brave....

I learn stuff from you all the time Steve, LOL

Bob.
 

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LOL! Don't blame me, it's this guy's fault...
 

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Discussion Starter #7
I don't think I'd trust those small push-on connectors for this. They're probably rated for 10 amps, maybe 15 max.
Given how many hot-wire kits have burnt up their 30a fuse holders you're gonna want something more skookum. They're probably fine for the coil circuit but once you get it all together and are sure about the wiring you should consider going back to butt-splice connectors on the pump wires.
Thanks. Will do for sure.
 

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Discussion Starter #8
Forgetting for a minute what connectors came already supplied on the relay wires, I think you need to at least switch the black and blue relay wires.
You would think there would be a common wiring color code for 5 conductor relays, but I did a Google search and the results were all over the place.
Common sense tells us the small relay wires (white and black) are for the coil and the thicker wires (yellow, blue and red) are for the contacts. DC relays usually work connected with either polarity, but some have a built in diode to protect the upstream circuit that powers it, specifically to reduce arcing on contacts from a coil's inductive load. So it's best to connect it properly.
Do you have a multimeter?
Also look very closely at the relay, most are marked in some way identifying the connections. Try removing the relay from the socket with the wires coming out, it could be on the bottom of the relay.
When I Googled I did see that for many wiring diagrams that the black wire was ground, which make sense since it was supplied with a ring terminal. So I recommend:
Relay Black - connect to ground (stud on the fuel hat)
Relay White - connect to black w/blue strip wire from the OEM Fuel Harness Connector
Relay Yellow - connect to new red wire from the battery
Relay Blue - connect to black w/blue strip wire to the fuel hat/fuel pump
Relay Red - not used, but must be insulated to prevent shorting out

If you have a multimeter, you can easily check the contact wiring from the relay - the yellow, blue and red wires, to check what I said above.
If you don't have a multimeter, and the above doesn't work let me know. I can tell you how to use what's there to troubleshoot and identify the correct relay wiring.

Let us know how it works out. Like I said if the relay does NOT have an internal protective diode, then it would work with the white and black wire switched, so the instructions would be correct. I would like to give 3SX feedback to update/correct their instructions in any event, since they don't match the hardware as they supplied it to you.

On your question about the metal fuel line - yes you need to cut off the end of the existing line so the hose will fit over the piece coming down from the fuel hat.
I changed the wiring according to your recommendation Turbo. Will put it in momentarily. The pump didn't look secure the way it was so I installed 2 zip ties to make sure it doesn't move.
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Discussion Starter #9
Ok so I figured out how the 3SX relay is supposed to be wired. The relay clicks and the pump works. However I am not getting any juice from the stock relay hot wire(black/blue stripe). I can activate the relay and pump via jump wire from bat feed(red) to relay activation wire(white). Fuse/relay blown?
YouTube link to video of relay/pump test:
 

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Keep'n 'em spooled
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The fuel pump doesn't get power by just turning on the ignition. The engine has to be cranking.
If that's what you tried and no voltage on that wire then yes, fuse or wiring problem.
 

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Discussion Starter #11
The fuel pump doesn't get power by just turning on the ignition. The engine has to be cranking.
If that's what you tried and no voltage on that wire then yes, fuse or wiring problem.
Yes. I set my multimeter, set my phone to video it, then got in and cranked a few times. MFI is clicking, is there somewhere else to check? I was under the impression that the MFI was immediately up current from the pump
 

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Discussion Starter #13
I am not able to read diagrams atm, will have to do a little self learning.

So going down the list of things I do know:
Fuse 12 is powered
MFI clicks when key turned to START, then again a few seconds after key turned back to RUN.
Fuel pump is powered. I have video of it.
Plugs smell like fuel.

I haven't checked the injectors but I am getting full power to spark plugs. So I have fuel and spark, air should be a given.

This is what it's doing now though
 

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Keep'n 'em spooled
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It sounds like your Hot Wire Kit install is successful, but now your car won't start. How long has it been since it ran? My car has taken quite a long time cranking over before starting when it has sat for many months. Do you have a battery charger? If yes then let the car crank for a long time, like 20-30 seconds.
If that doesn't work I suggest you research threads for car not starting and/or start a new thread of your own "car won't start".
 

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Discussion Starter #15
Ok will do. I'm going to take my battery to auto zone and have it properly charged then I'll try the long crank. Car almost backfired once when I first cranked it after priming the pump for a few secs.
 

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Discussion Starter #16
Turbo, I hooked some jump cables to another car to hold charge and cranked for about 20sec three times and it sure enough fired up. Thank you so much for your help and advice during this job. Correction, thank all of you. Now to button up and go let it run for a while.
 

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Turbo, I hooked some jump cables to another car to hold charge and cranked for about 20sec three times and it sure enough fired up. Thank you so much for your help and advice during this job. Correction, thank all of you. Now to button up and go let it run for a while.
Glad to hear it and you're welcome for the help. It drove me crazy trying to figure out what was wrong with my car (nothing) first time it took a long time cranking to start.
 

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Hey guys, we've updated the design a few times ( inconsistent relay suppliers) and have since updated the instructions from the OP of this thread.

Here are the official wiring instructions for the newest kit, using the power map from the relay supplier:

  • Remove the 30-amp fuse from the fuse holder for installation.
  • The included 10-gauge power wire runs from the battery to the fuel pump under the hatch. Connect the pre-terminated o-ring terminal (the fuse end of the long wire) to the positive battery terminal. Run the power wire to rear hatch area. You will find the fuel pump sender cover in the rear right side of hatch under the spare and cargo tray - remove cover panel.
  • Cut the 10-gauge power wire to the proper length and connect it to the pre-terminated RED power wire on the relay harness.
On the fuel sender lid you will find a black-with-blue-stripe wire. It runs into the fuel pump harness plug. Cut this wire in half.

* Connect the pre terminated BLUE relay wire to the black-with-blue-stripe wire leading to sender lid (TO FUEL PUMP side of the cut wire).
  • Connect the pre terminated WHITE relay wire to the black-with-blue-stripe wire leading to the fuel pump harness plug (TO CAR HARNESS/SUPPLY side of the cut wire).
  • Ground the pre-terminated BLACK relay wire with the o-ring terminal.
Re-install the supplied 30-amp fuse into fuse holder at the battery

  • Check install by running car to ensure the pump is getting power.
Notch out fuel sender cover to allow space for wires. Reinstall cover.

286427
 
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