Some electrical issue..

[skyline084]

When the car is switched off or unplugged it's 12v.
When I turn the Ignition ON, it drops to 10v, than continues to drop as long as I keep the Ignition ON for.
The motor fires, and will start , but then immediately dies.
What could cause that voltage drop?
Any

[ghost_22_47]

Well the most draw on the battery is from the Starter, but did you check you alternater?

[skyline084]

I haven't yet, but I will. I just don't understand why power is being drawn just with ignition ON.. It won't lose any voltage with the key out. The motor doesn't idle or anything.. For me to even start this thing, I have to run a battery charger to it just to get enough voltage, because it will drop from 10v to 8v in 5mins.
I just need to know a 'general' reason to why voltage would drop

[gmac708]

When the car is switched off or unplugged it's 12v.
When I turn the Ignition ON, it drops to 10v, than continues to drop as long as I keep the Ignition ON for.
The motor fires, and will start , but then immediately dies.
What could cause that voltage drop?
Any

Usually big current draw. Unplug some non essential fuses can be a big help troubleshooting. Start with the big ones.
Also try swapping out/testing the battery, does it run with jumper cables? Also check ground points and terminals for good clean contacts. They can cause some high resistance/high current draw. Can you here the fuel pump run?

[skyline084]

Okay, I'll check all the fuses tomorrow. It's a fairly new battery, and holds a little bit over 12v.. it normally would be around 12.30, but I've been cranking it without starting it to do tests so it drained just a bit.
It doesn't run at all right now. I need cables to just get enough voltage to start it, because as soon as I switch the key to ON, it drops.
I checked grounds, added a jumper cable from the battery to the block too.
Fuel pump primes good, Fuel pump relay's good too.
Got spark, fuels spitting

[skyline084]

Also
I'll be checking all the wires again tomorrow.
What number of ohms should I be receiving when I run tests for continuity between all the wires?

[Carl H]

battery sounds toast...believe it or not just because its 'around 12v' doesnt mean its good.
infact i believe if your voltage is around 12.3v its actually classified as dead.

[skyline084]

It's always been around 12.3 and ran perfect though?
I'll try throwing this battery in my other car and see what happens.
This is the problem my car's facing though after reading through the wire harness for hours and finally understanding it.
o2 sensor got unplugged which is where the code 54 was coming from. (A/T circuit and o2 tie into one another)
Because of this, air/fuel ratio was retarded, and it made me run super Rich.(Plugs are black,wet)
I cleaned plugs, got o2 connected, but it fires, and immediately dies. Giving it gas does nothing.
It's also very low voltage, possibly b.c I completely disconnected the system when I removed power from lower and upper harness's.
Today I am going to check for power/signal/grounds at the CAS, AFM, o2 sensor.
I get fuel and get spark.
Question: Could I be getting spark with plugs that are shot? Even if they are shot, wouldn't it be enough to make the motor start and idle, even if it's rough.. It was a pretty solid blue spark.
Any info is appreciated.

[Carl H]

just because you get spark does not mean its a good spark, a nice powerful spark is almost violet in colour.
it sounds like its a combination of things, mainly a weak battery...but also timing is most likely retarded as its a auto ecu.
o2 and autologic are completely different circuits; o2 has no code where autologic does.
put a new battery in the car (12.6-12.7v when tested) and once it runs check base timing...also depending on who did the wiring check for blown fuses, as power routing can cause weird issues if a fuse is blown.

[skyline084]

Okay, I switched batteries because mine was def. weak and on the way out, which is why i needed cables to charge.
Wouldn't that spark be enough for the car to at least start and idle though?? even if it's a rough start and idle?
Reason I thought o2 was connected to A/T was b.c it says in service manual that o2 wire number 3 goes to ECU pin #15, which is Engine A/T control input signal(DT3)(A/T)

[Carl H]

dunno what fsm you're referencing but in all the harnesses i've ever torn apart i have never run across the o2 sensor and autologic being mixed.

[skyline084]

I got it from here, http://www.nicoclub.com/FSM/rb/R33_All_ ... Manual.pdf
I don't understand what's going over in the A/T section there,but look at diagram on page EN-321

[skyline084]

I didn't do anything besides unplugging the 2 relays next to the ecu (Pump, and Ecu) and plug them back in.
Car actually turned over and idled for a minute, than died as soon as I gave it heavier gas.
It seems that the spark is coming and going
I'm always getting fuel though