Help! RB25DET won't start

Discuss the RB20, RB25 and RB26 series engines.
droptopsf98
Posts: 45
Joined: Fri Oct 02, 2009 2:22 pm
Car: 1989 240 SX SE pending RB25 swap

Post

I have an S2 RB25DET engine in my S13. Car is an 89 SOHC Auto Non-ABS chassis if it matters. I'm fairly certain I am lacking spark. My compression is good. I took my coilpack/boot/plug and set the plug threads against the turbo manifold to see if I have spark when cranking....I do not have spark when doing that.

I'm not really sure on how to check where everything is sourced. I've opened the FSM and done what I can from my limited ability to read the thing. I've managed to prove that I have +12v on my white wires on the coil packs, and that my grounds are all working on my ignition harness by checking OHMs. I got .04 OHMs consistently across all 6 wires. I assume the pink wire is where my signal comes in to fire the coil. I have looked all over for the "ignition relay" and I honestly have no idea where it is. There's what appears to be a small relay in the vicinity of where the ignition harness plugs into the upper harness but it only has 2 wires going into it. I noticed several S1 ignition harnesses having a ring terminal ground on it...mine does not have that. (Might be missing it, might not need it since I'm an S2 engine)

I bought this car as a chassis, and I bought the motor used so I'm learning everything by just putting it together. Unfortunately I didn't get to take it all apart which makes this challenge quite difficult :(

If someone could just tell me what I need to read with my meter to help me get going that would be GREAT.


droptopsf98
Posts: 45
Joined: Fri Oct 02, 2009 2:22 pm
Car: 1989 240 SX SE pending RB25 swap

Post

I just verified voltages at the CAS.

White wire gave me 8v with the key on, and 5v while cranking.

The 2 blue wires each gave voltage that varied from .15v to ~4 volt while cranking. Any idea what else I can check?


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