R31 [RB20DET] No Start

[colata]

Hey guys, first post so make sure if its incorrect, etc. drop a comment down below showing my how to fix in the future.

 

Got a no start on my RB20DET R31.

Information prior to the no start condition:

Car was idling, has been running for weeks fine, recently fixed a leaking o-ring at the fuel rail, and while it was idling after the repair i was attempting to get the cluster temp guage working from an RB30e temp sender to the single spade connector on the factory 20det harness. Accidentaly tapped/bumped the spade (connected to the harness) against the block / thermostat plumbing and the engine just cut out and died instantly. No sputtering, etc. died as if the key had been turned off, very strange and could only imagine its some voltage serge situation.

Information relating to my diagnosis that may or may not be relevant but i thought id include:

- Fuel pump can be heard running on "ignition ON", FPR reads 0kg/cm fuel pressure, but increases to around 1-2 (30-40 or so psi) when the hose is squeezed.

- Secondary ECU has been trialed that is believed to be healthy but haven't tested for myself, only word of mouth.

ECU Pins: 

50/60 - Closed circuit 

10/20 - Closed circuit

107/108/116 - Closed circuit 

26 - Closed circuit 

58/49/59 - 12v + (ONLY WHEN PIN 16 IS MANUALLY GROUNDED)

109 - 12v + 

45 - Believed to be possible open circuit, will be re-checking and updating asap.

Extra notes: 

ENGINE CRANKS FINE.

- Pin 16 has 12v to the ECU harness but does not activate ECCS relay when "ignition ON". BUT when manually grounded to chassis (bypassing ECU) ECCS relay activates and pins 49/59 recieve 12v+ to the ecu harness.

- CAS has ground and 12v+, when spun by hand 1 degree wire cuts 5v respectively (per 1 degree), but the 180 degree seems to be all over the place, more like 20 degrees separation. Also when spun by hand, injectors and coils CAN NOT be heard firing.

- Injector 6 has been tested with a noid light on crank and revealed NO pulsing, entire rail has also been tested out of manifold with no injectors visibly firing on crank.

- Coil 6 has been tested with a plug in the boot, out of the head and no spark was seen.

P.S Ignore the scribbles on the photos, most are there when i've gone on tangents and probably reveal nothing about the problem, just me trying to clear the diagrams in my head, I included them simply for reference in the event they are incorrect / outdated, etc.

Any help is appreciated at this point, it's probably really obvious but i'm driving myself crazy over the past couple weeks with this and as im beginning to take on more work i have less time to goose chase and need to regain a sense of direction for what i should be investigating, thanks!

- Sam

 

[GTSBoy]

Surely it has to be a fuse?

[colata]

50 minutes ago, GTSBoy said:

Surely it has to be a fuse?

If you could point me to where i would be finding fuses for the ECU, etc. on an RB20 swapped 31 / rb20 loom that would be appreciated, the engine cont. fuse (factory fuse box) under the wheel is good and as far as ive been able to find, the rest related to the ECU would be the fusible links, which i have checked and are all ok 

[GTSBoy]

Nope.  Sorry.  Not my cup of tea.  Just seemed like you had the "Shorted something (your temp gauge wire) out.  That something is not directly connected to the ECU, so probably didn't burn anything in the ECU" type of event that usually then leads to a fuse popping.  Some parts of your system still have power, but others don't.  Sounds like a fuse.

[colata]

Update to my findings.

Found that the ignition relay (pin 1) had no continuity, so manually grounded it, completed the relay circuit but still did not change the no start condition.

Pins 43/45 Also had low/no voltage, but unsure if that should be the case or not, pointers would be helpful.

 

Edited November 2, 2018 by colata