laurentj23

iTrader: (27)

Hey all,

Im doing a lsx swap for my nissan 240sx. I purchased the wiring harness from wiring specialities. The project is almost completed. What stopped me is the wiring issues that I have. Here are the problems.

1. I bought a distributor block and route the positive battery to the block and the 2 outputs are for the starter and fuse box. So far my interior lights light up.
I grounded the negative battery cable to the chasis. Do i need to have another wire and ground it to the block? Where does the other end of the wire goes? the chasis?

2. When I tried to crank the first time, the fuel pump prime and the engine turned one time. Now, I tried to crank it again, the starter just click and the fuel pump did not prime. What is going on here? I check the the fuel pump relay and it did click. Do I have no power to the ecu?

PleSE help! thanks!
The battery, cables and starter are all new.

33willys

iTrader: (1)

The battery circuits require large wires and good grounds. For the positive side run a wire such as welding cable (Tractor Supply) to your distribution block, then run the same size wire to the starter solenoid. For the ground wire use the same size wire as the positive and run it to the starter mounting bolt with jumpers to the frame and body. I recommend star washers and crimped lugs. Sounds like you have a "choke" point somewhere, maybe a to small wire or poor ground.

Nissan LS240

iTrader: (1)

starter is case grounded, meaning it uses the block to go to ground, and if you have no ground wires going from block to chassis, it will try to find ground through trans, driveshaft axles bearings wherever it can go to find ground, which is why it worked for a little then probably burned something in its path, most likely in the wheel bearings, whatever size wire youre using to feed the starter ground the motor to the chassis, doesn't have to be grounded right next to the starter but its better to keep it close, I have 4 grounds on the motor, one on each head, and one on each side of the block, overkill maybe but don't want any high amperage electricity going through bearings

laurentj23

iTrader: (27)

I think i figure out what the issues are. I have no ground at all from the the block to the chasis. The only ground i have is from the harness to the drivers head.

Can i just ground it from the cylinder head straight to the chasis or do i need to ground it from the starter which is going to be 3 wires on the starter. Constant wire from alt,positive cable that goesn into the distributor block and ground cable?

Heres a diagram on how i route it.

laurentj23

iTrader: (27)

This makes a lot of sense! Thanks

6speediroc

iTrader: (5)

Run the battery negative straight to the block or head. Also run a ground strap from the block or head to the chassis, and from chassis to body if not a unibody car.

My factory battery negative cable goes direct to the head, and also has a 8ga lead to the fender (unibody car).

Nissan LS240

iTrader: (1)

I guess we should ask where is the battery located, I put my battery in the trunk and grounded it in 2 places in the trunk, if your battery is under the hood then grounding the battery to chassis and block is a better choice than just the chassis, as well as another ground wire grounding the block to the chassis

laurentj23

iTrader: (27)

Ok this is how I grounded it.

Passenger's side head



Driver's side head


This is how I did the cable to the distribution block


Turn the ignition, still click. Keep turning and now it won't click and no power at all. Fuel pump did not prime. and relay did not click.

I've checked fuses and everything is good.
Battery is at 12.6 v
Gonna test the starter today

Any other suggestions?

laurentj23

iTrader: (27)

Just an update,
I check the volt reading on the ignition switch. O when its not turn off except for 1 wire than 0 reading on all wires when turn the key to on.

rouseyss

Did you try what NissanLs240 stated? It sounds like he knows a lot about this topic and he has completed that exact swap so that's a good start. Let us know when you find the issue. And show some pics of the swap, it looks like its pretty nice!

Nissan LS240

iTrader: (1)

The only problem is I ditched the factory wiring and ran my own fuse block, so if he has a problem with the wiring I'm not sure what wire goes where, all my ignition switch does is unlock the steering.

laurentj23

iTrader: (27)

Pretty much. Im gonna ground the neg battery to the block tomorrow.
I've a build thread. But everything is on hold till I get this wiring thing sorted out. Are you using an aftermarket starter button?

Nissan LS240

iTrader: (1)

yes, one switch for fuel one switch to power everything, and starter switch, have some extra switches that have to be in a certain position to start the car, just to keep someone from driving off in my car

laurentj23

iTrader: (27)

How do you wire it up to the switch for the starter?...Im using Jegs switch

Nissan LS240

iTrader: (1)

tap into a 12 volt source, I wanted mine to be able to turn over with everything powered off so I tapped into the feed wire for my fuse block that stays powered all the time, and run the other side to your starter remote wire, smaller of the 2 wires on the starter, I added 5 switches before the starter switch that have to be in a certain position to send power to starter, lots of people have access to my keys don't think anyone steal it but don't want anyone going for a joyride, also have a hidden switch for the fuel pump

laurentj23

iTrader: (27)

Pics of the wiring? Can i just tap the wiring on the ignition switch and add the wiring for the aftermarket switch? And I grounded the neg battery to the block as well. still no power. Im 95% sure is the ignition switch.

Nissan LS240

iTrader: (1)

I don't have original dash, and factory wiring is removed, so not going to be much help

laurentj23

iTrader: (27)

aH DANg it. OK so I tested the starter and when I put my positive lead on the multimeter on the hot side, the motor will turn. I checked the harness that plugged in to the ignition switch and it doesn't read 12v battery plugged in. Is that normal?

Nissan LS240

iTrader: (1)

on the ignition switch, one wire should always have 12V, if you have a wire feeding the fuse block under the hood then you either have a broken or bad connection, a blown fuse, or no fuse, I know you said you checked all the fuses so I would double check the you have all the fuses installed in the correct location, and when you said checked fuses you use a test light or volt meter or did you pull out and checked them visually? just asking because just because a fuse is not blown doesn't mean there's power going to it,

laurentj23

iTrader: (27)

I checked the fuses with test light and visually as well. Here's a video I made