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S1 rb25/s14 starting problem

25zenki

By 25zenki,
in Engines & Forced Induction

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25zenki Rookie

25zenki

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48 minutes ago, MBS206 said:

Check the injectors flow evenly, and are actually flowing what you and the ECU think they should be flowing.

If it's starting up on starter fluid, you have a fuel issue.

Is it possible under cranking your fuel pump is turning off?

 

The harness you replaced, is that the whole engine harness?

Do yourself a test, and drop the old harness on and plug it into the Z32 ECU. It's possible they've wired things different.

From memory S1 to S2 is different in RB25 and you may have a wrong loom

Harness is for a s1 Rb25det, and it is engine and lower harness.  the old harness had broken off plugs and was in very rough condition/exposed wires and splices etc. it is not able to be put back on the car, I could visually inspect to see if they had rewired any pins on the ecu plug. The fuel pump definitly isn’t turning off it’s an external pump and very loud you can hear it. Will look at the other harness tonight, am also going to pull the fuel rail and watch the injectors spray, will update here with what I find. Pretty sure at this point it has to be something to do with injectors because car will fire up on starting fluid and cas is clicking the Injectors. Fuel pressure is steady 43psi 

Duncan Grand Master

Duncan

Posted
Posted

Depending on how long the car sat it is very possible for injectors to be stuck open or closed, I'd get them cleaned and flow tested.

Other than that, obviously when the loom changes and the car doesn't start any more....the loom is suspect so some tracing / comparing may be required

MBS206 Grand Master

MBS206

Posted
Posted
1 hour ago, Duncan said:

Depending on how long the car sat it is very possible for injectors to be stuck open or closed, I'd get them cleaned and flow tested.

Other than that, obviously when the loom changes and the car doesn't start any more....the loom is suspect so some tracing / comparing may be required

I'm with you here.

It's either loom has an issue, OR, injectors are not functioning properly. It could even be they're just constantly dribbling, hence the wet, but not firing.

GTSBoy Grand Master

GTSBoy

Posted
Posted

Check the Nistune doco. There are a few assumptions being made here that might not be valid. I will list the things that occur to me:

  • Base map.
    • Base map for what? Base map for Z32? Then the cranking pulse width is probably wrong for an RB25. The extra 500cc of capacity might well be enough to prevent it from catching.
    • Base map for RB25? I don't think you can load one of those into a Z32. You have to just make the settings correct for an RB25 in the Z32 base map. That is either K or the TIM to get the pulsewidth right.
  • Loom.
    • You bought a loom for an RB. And you plugged it into a Z32 ECU. Did you make sure that any iwre differences were swapped. From memory, there's at least a couple.

And as per the others, I would suggest making sure that the fuel pressure is correct while cranking and that the injectors are actually flowing as expected. They really must come out and go on the bench, unless you do find that you have messed up as per above points.

I would also suggest watching in Nistune to make sure that everything is reading correctly. That the correct binary flags are raised at the right time (like the crank signal), that there's no stupid values in K or TIM. That you have not got mismatched firmware for the ECU and/or a wrong image loaded.

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