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Hi all,

I have a problem with a brand new power fc, it wont energise the fuel pump solinoid and as a result the engine is starved of fuel. now i have put the stock ecm back in for now and have tested all the electrical circuits to do with the fuel pump, eccs relay and fuel pump controle modual and all apear fine. so I think the ecm is just not negativele switching the relay when it is suppose to.

Now I have bought the pfc over east and before I start the whole shit fight of getting it replaced under warrenty, I want to make sure it is the ecm and not anything in the car. and want to try it in another car.

The Problem is I dont know any one else with an r33gtr to try it in and most people with one wouldnt want some guy they dont know poking arroud swaping ecms over in it.

So If there is anyone who could help me out with this. it would be greatly appreciated and you would be rewarded with a carton.

;) , Mark.

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OK, I got hold of the wiring diagram and realised that I did not undestand what the fuel pump controle modual is and did :D . I now know that it puts the negative side of the fuel pump to ground and when you bypass that and put it straight to ground the pump works correctly.

What I dont understand is why it dose that (is it checking current draw as safty mechanism for a failing pump)

and why the power fc dose not controle it correctly?

and is it ok/safe to bypas it as I have.

Im going to repost these questions in the main tech section as well.

regards Mark.

hey mate

i had similar problems with my ecu

there are two power sources for your ecu. while your factory ecu will work fine and runt he fuel pump and everything with only one power source, the aftermarket ecu requires two working power sources, otherwise you find that the voltage drops below what is required to power the ECU

check your fuses under the dash - if you find one is blown, this answers your question. If not, you need to check the wires powering your ecu, to check whether or not your ecu is receiving power on both of those pins ;)

hope ive helped. cheers

:)

hey mate

i had similar problems with my ecu

there are two power sources for your ecu. while your factory ecu will work fine and runt he fuel pump and everything with only one power source, the aftermarket ecu requires two working power sources, otherwise you find that the voltage drops below what is required to power the ECU

check your fuses under the dash - if you find one is blown, this answers your question. If not, you need to check the wires powering your ecu, to check whether or not your ecu is receiving power on both of those pins :D

hope ive helped. cheers

:)

Thanks tommyk I checked all the power and earth circuits to the ecm and they are all fine, all fuses werefine also, I have just run the negative side of the fuel pump to ground to get the car going and now the thing wont run properly it runs like it has a bad vacume leak but there isn't one. need try this ecm on another car to eliminate the ecm out of the equasion.

fuel preasure is a stable 45psi , no leaks , compression good, cam timing good, ignition timing good, even tryed the afm wiring in different ways to see if that made any difference. cant work out why itsdoing it, starting to shit me bad.

OK, I got hold of the wiring diagram and realised that I did not undestand what the fuel pump controle modual is and did :rolleyes: . I now know that it puts the negative side of the fuel pump to ground and when you bypass that and put it straight to ground the pump works correctly.

What I dont understand is why it dose that (is it checking current draw as safty mechanism for a failing pump)

and why the power fc dose not controle it correctly?

and is it ok/safe to bypas it as I have.

Im going to repost these questions in the main tech section as well.

regards Mark.

This is AFAIK a factory measure to reduce NVH - gtrs, gtst, silvias etc all do it.

The power fc is a piggy back design built on to a factory ecu and contained in the one box, so it should work fine - obviously.

Do you have the pfc boost control kit with your power fc? if not, did you switch the option off on the hand controller in the ETC menu?

If you dont have the boost control kit, and didnt switch it off with the hand controller, this may be your problem.

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