I can have the fuel pump wired direct but I rather have it wired through the ECU for safety.

Two pins on the ECU relate to the fuel pump. Pins 11 and 15. Pin 11 says 'Fuel Pump signal to relay ground' and pin 15 says fuel pump control.

Basically I wired the positive directly (with a fuse for safety) and of course the pump comes on if I ground it. But Im not sure how pins 11 & 15 relate to this and how im supposed to wire them so the pump primes when you turn the key to ON then stops after like 2 seconds like stock. Is a relay absolutely necessary for this?

 

read post 22 and 23, hopefully this helps

http://forums.maxima.org/showthread.php?t=513525

 

J, a relay is way more important than getting signal from the ECU. Very slim chance the ECU could supply enough amperage to run direct power to the pump. What isn't safe about running the pump on a seperate switch? May I assume that you're worried about a crash or roll? In this instance the ECU will still be getting power and thus still be pumping fuel. So you would be no less or more safe for running through there. The truely safest method would be to utilize an inertia or rollover switch to all the power systems. I've been looking into that lately.

 

Yeah Ill just use the stock relay as it is meant to be OEM. I tried to fire it up today and unless im on crack it really seemed that it wanted to start till the pump started to act funny. Needs REAL big wires I think. The Walbro demands it.

BTW the engine bay wiring+dash wiring weighted 32 pounds off the front end alone.

 

^Wow! 32Lbs! Holy t!ts! I was thinking maybe 15lbs but d@mn.

Right now I'm only running 12 awg wire to my A-1000 and it doesn't get hot at all. Fuel pumps don't have a huge draw.

 

Yeah well I was worried because I have a Walbro. Now the fuel pump seems to works fine now and has its own relay for safety. Its not wired through the ECU at all. Really, unless im nuts the engine sounded like it was on the brink of firing up till the starter blocked it and ended the attempt right there.

I had one nut and one washer on the two bolts between the starter and the pan as a spacer but it doesnt look like its enough. What distance exactly is yours spaced out? The bendix doesnt seem to pull out or its just altogether too close... I think im gonna try two nuts and no washer.

 

Well Im not nuts, the S13 just fired up! Ran for like 2 seconds then stopped, alternator belt screaming and all - but what the hell, that means my 'from scratch' custom main wiring harness actually works! I gotta tear it back down for the water pump seals and still have about a week's worth of work to get it to roll, not to mention all the troubleshooting, hood customization, interior, body wiring harness, etc. but this proves that the harness works fine.

 

I'm confused, why wouldn't you use the wire from the stock fuel pump relay to trigger the new relay that sends 12 -13 volts right from the battery to the walbro pump??

 

She's alive! Nice. Its so satisfying when that happens.

My starter is spaced out with one monster @ss nut. I have no idea how thick it is.

I would definitely think a Walbro should have less draw than an A-1000. I think you're totally fine in that arena.

How did you go about making the harness. Did you totally depin the ECU plug? Or did you splice into the wires just out of the main plug? I'd like to do this as well.

He has no stock relay anymore Krab.

 

I cut all 125 wires about 6-7 inches from the ECU plug. I have 2 and a half spare harnesses or so so finding all the plugs was no problem. The 95 ECU only needs around 60 out of those 125 wires to run smoothly. That includes the 6 coil packs, 6 injectors, 3 main crank-cam sensors, MAF, TPS, Coolant Temp sensor, Knock Sensor and all 3 oxygen sensors.

Once done its gonna look pretty clean in the bay.

Back in June 06 the front of my car looked like yours now (saw this on a drag S13), with the two tubes running from the top of the shock towers down onto the frame - then a straight tube and about a foot of cut frame:



Saw this one on your cardomain a few days ago. I wised up this winter since mine is a street car prone to inspections. So I keep the two shock tower tubes, but cut the straight one and made a bent one that bends on both sides and angles down 6 inches (for the radiator support). Then I welded the shock towers back on, and will weld some thin sheetmetal under the shock towers to hide the tubes, and stock plastics for the transverse tube.

From the engine bay the tube disappears behind the stock shock tower and reappears at the bottom. The upper portion will be hidden by relay boxes if it passes an inspection.

Ill post a thread with pics and impressions in a week or so when it actually rolls...

 

thumbs up twice, buddy!! hope to see this beast running this summer, give me a notice, gonna come to your home to check it out!!

 

Thanks! The car is gonna stay on the lift for the next few weeks (i.e not gonna drive it a half hour to my place till I know its reliable), but I will start hitting the tracks in the second half of April.