Conversions & Swaps LSX Engines in Non-LSX Vehicles
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Old Oct 13, 2011 | 09:37 PM
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Default no fuel pump

i'm in desperate need of help. the car is so close to being fired up, and yet it's just sitting here like a piece of crap paper weight, and i don't know where i need to look next to get it running.

the fuel pump isn't priming. the dash lights come on, the clock works, taillights work, but the fuel pump wont prime. it's a 97 240sx with a 2000 SS ls1.

i ran the battery directly to the fuel pump to see if i had connected the wires incorrectly, but when i swapped my jumper wires to the leads of the fuel pump plug, the pump still primed, so it was pumping backwards, hah? are they supposed to do that? it's a walbro pump.

i'd appreciate any help, because i have no idea how to diagnose this problem.
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Old Oct 13, 2011 | 10:48 PM
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Running backwards? Did you have the leads connected wrong?
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Old Oct 14, 2011 | 06:44 AM
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Is the fuel pump connected to the 'Supply' fuel line? What regulator are you using and where is it located? And to reiterate what Ratbox said, did you wire the pump backwards?

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Old Oct 14, 2011 | 08:15 AM
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Is the fuel pump wire from the ECU sending a signal to the stock 240sx relay? You're running a harness modified by Sikky, correct? Maybe check with them and see if that is something that you have to wire up.
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Old Oct 14, 2011 | 03:43 PM
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Originally Posted by RATBOX
Running backwards? Did you have the leads connected wrong?
do you mean when i cut the original wires to the stock pump? that's one thing i'm trying to figure out. whether i connected the power wire to the red walbro pigtail wire. one wire was red and the other was red with green stripe. i assumed that the solid red wire is the power wire.

the fuel pump cover is on, i'm just running two wires from a battery to the two prongs on top of the fuel pump cover. if i put the positive to the right prong, and the negative to the left prong, the pump kicks on. the thing that confuses me is that if i reverse that, the pump still kicks on. positive to left prong, and negative to right prong. gaw, i'm sure i'm making no sense. sorry.

Originally Posted by psiconversion
Is the fuel pump connected to the 'Supply' fuel line? What regulator are you using and where is it located? And to reiterate what Ratbox said, did you wire the pump backwards?
i'm using the corvette filter/regulator and it is right above the fuel tank.
similar to this picture. http://i55.photobucket.com/albums/g1...X/IMGP0399.jpg

i'm pretty sure i'm using this configuration.
http://img129.imageshack.us/img129/9745/inletwn8.jpg
the inside fitting(orange) goes back INTO the tank, and the outside fitting is being fed the fuel.

i wish i knew whether i wired it correctly, haha. i guess i could always remove my crimp job and swap the wires and see if that works? but see the description of the wires above and see if i made an educated guess.

Originally Posted by rigid
Is the fuel pump wire from the ECU sending a signal to the stock 240sx relay? You're running a harness modified by Sikky, correct? Maybe check with them and see if that is something that you have to wire up.
you're talking about the reverse polarity mod, right? i've called sikky twice and they said i shouldn't have to do anything.
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Old Oct 14, 2011 | 06:38 PM
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Try wiring the battery directly to it, then hit the key and see if it starts. I think you might be over complicating this.
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Old Oct 14, 2011 | 08:00 PM
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When my engine first started up I had a toggle switch running to the fuel pump and a momentary switch going to the starter. Just do whatever you can to get that thing fired up. I have a feeling once you start it once you'll quickly figure out the small bugs so you can get it on the road. If you can't figure it out, I'm sure Kevin and/or I could come over this weekend and get it started.
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