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Injectors Constant Power

SiR_RB

By SiR_RB,
in Engines & Forced Induction

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SiR_RB Grand Master

SiR_RB

Posted
Posted

Since i got my new GTR I noticed with ignition off, the injectors were making a buzzing sound and showing 6-8v, today we spent all day trying to find the issue, what we came up with so far:

Disconnect ecu and injectors still have power

Disconnect ECC relays behind ecu, injectors still showing power

Disconnect each relay in engine bay one at a time, no luck

Battery is in the boot and has an isolation switch in the engine bay. If we turn that off they dont get power and everything is good (as expected)

Has anyone experienced this before ? Is there anything else I can check ?

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https://www.sau.com.au/forums/topic/463835-injectors-constant-power/
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XGTRX Veteran

XGTRX

Posted
Posted (edited)

Someone may have directly wired the injectors not through a switched source. Alternatively the loom may have been damaged somewhere - need to trace it back with a multimeter.

Exactly right. Someone has rewired the constant power to a battery source due to a loom problem. Just find the wire and put a relay on it with an ignition supply.

Common and easy fix for ignition loom problems also.

Edited by XGTRX
SiR_RB Grand Master

SiR_RB

Posted
  • Author
Posted

So I should strip back the loom and find the main positive supply cable for the injectors then wire a relay? Seems like an easy fix

Only shit thing is my loom is under the hypertune plenum, guess it has to come off again, unless that wire is on the ecu plug side in the passenger foot well ?

SiR_RB Grand Master

SiR_RB

Posted
  • Author
Posted

Obviously the loom gets a 12v power supply to run the show

Can anyone tell me where abouts this direct power feed comes from? I want to make sure no clown has connected any injector supply/control cables there

89CAL Grand Master

89CAL

Posted
Posted (edited)

There's a relay in the passenger footwell on R33's. Assume 32's would be the same. From memory power supply into the resistor pack and then it splits to the injectors individually from there

Grounded individually through the ECU on the way back.

Just had a look (at the R33) drawing, looks like power supply to the resistor comes straight from the key IGN

Grab meter and start probing. Maybe a wire has been mixed up on the ignition barrel

Edited by 89CAL

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