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No power to hardwired fuel pump

2928 Views 10 Replies 4 Participants Last post by  Enoki_X
Running into an issue and hoping for some guidance. I have a hardwired Walbro 450. The OEM signal wire is used to turn the pump on/off.

I recently installed a Radium fuel hanger and moved everything over to that. Once the swap was done, it fired up right away without issue. I had installed the fuel level sensor arm incorrectly, so I took it back out to fix that. After putting everything all back together, I am no longer getting power to the signal wire for the fuel pump.

I've pulled fuse 23 and 24 from the relay box under the hood, neither appear to be blown. I've also swapped all of the fuel pump relays (I have an extra set). Still not getting anything

My next step is to bypass the signal wire and get power directly from the battery to see if it cranks.

Is there another fuse or something obvious that I am overlooking here that would prevent the signal wire from getting power?

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Also, as a note - my ECU starts up fine and is not throwing any codes
This is what I used to wire my walbro 450 pump and has a relay . It connects to the battery . Then you give a ground abs take the thick blue wire underneath the seat and splice into that triggering the relay . The red wire will connect to battery with a fuse
I use the same kit. Power/ground to the pump is coming from a relay that is connected to the battery. The blue signal wire for the OEM pump is still used to turn the relay on/off though

I just disconnected the blue signal wire and ran a connection straight from the battery into the relay, pump powered up immediately and was able to pressurize the system

Any ideas what could prevent voltage from coming over the signal wire when I turn the key? There has to be a fuse or something that I am missing here?

I have pulled fuses 23 and 24 from the relay box under the hood, and swapped all relays. Is there a fuse under the kick panel that I should look at?
hmmm the blue wire wasn't even touched when I removed the hanger again. it goes from the the OEM connection straight to the relay and completely bypasses the fuel hanger (just tucked off to the side). multimeter shows 0 voltage on the pump signal when cranking

ground wise:
-there's the fuel pump ground, which is good, as I can get the pump to fire if I provide voltage into the relay from the battery
-there's the ground which is shared between the fuel temp sensor and the fuel level sensor, but both of those appear to be functioning
aha, got it!

looks like there is a ground fault on my fuel temp sensor. as soon as i disconnect it, everything works as expected and it fires right up

looks like the basket is coming back out, but at least it should be an easy fix

thanks for your help!
I am having something similar and can’t figure it out. Randomly car won’t won’t start and fuel pump won’t kick on. Which ground wire was shorting on yours? And how did you find it?
it was the shared ground for the fuel level sensor and fuel temp sensor. i found it by taking out the basket and checking every single connection

i have the radium hanger where you have to cut the connector off and splice this wire
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