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Faulty Fpcm? No Signal To F/p

R.3.2.G.T.R

By R.3.2.G.T.R,
in General Maintenance

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R.3.2.G.T.R Grand Master

R.3.2.G.T.R

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Posted

so my R32 GTR randomly decided it doesnt want to start anymore, fuel pump no longer runs with ignition on

fuel pump had been re-wired for direct battery voltage and FPCM had been earthed so pump was alway on full voltage

checked the relay clicks (near ecu), directly jumping the fuel pump is fine, so issue appears to be signal to relay, swapped over relay in the boot and horn relay to another but no dice

checked engine bay and cabin fuses - all good

re-soldered a dry looking solder on pin connector of FPCM and re-did earth - no change

checked earth and power in boot, next to check the ecu (pfc handcontroller does not show F/P running till cranking - whereas with FPCM earthed, used to run continously on ign)

what's the go with pin 18 on the ECU, is it for ground or power signal to relay?

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89CAL Grand Master

89CAL

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Posted (edited)

Fuelpump_zps02b28fb5.jpg

IGN power to the top of the coil on the realy, then earthed through Pin 18 on the ECU

So if you don't have power on the relay coil siide with ignition on, then you have a power problem, If you have power then quite possibly an ECU issue

Depending on how you have done the Direct feed to the pump, it may still be utilizing the the FPCM, in which case you can get rid of it completely but just running the Battery power to one side and the other straight to ground. There is no need to keep the FPCM

Should be able to work it out with that diagram anyway

Edited by 89CAL
R.3.2.G.T.R Grand Master

R.3.2.G.T.R

Posted
  • Author
Posted

Thanks for the diagram, appears to be a power short somewhere, f/p fuse keeps blowing on ignition and no 12v to relay in boot

have disconnected ecu and front passenger side relays and still blowing, going to check wiring on cabin fuse block

89CAL Grand Master

89CAL

Posted
Posted

So 15amp fuse (Fuse #41)? It's not something silly like someone has put the wrong fuse in there?

That fuse is purely for the fuel pump relay by the look of it. Can you confirm that the fuel pump works?

Also have you bypassed the FPCM so it just goes straight in the pump and then to ground?

Really it can only be the relay or the fuel pump once you ground the other side of the pump (ignoring the FPCM)

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