Jump to content
SAU Community

Recommended Posts

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.

Link to comment
https://www.sau.com.au/forums/topic/92265-33gtr-pfc-problems/
Share on other sites

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.

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • 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
    • 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 
    • 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
    • I haven’t pulled the injectors to watch them spray yet but they are clicking from the cas and all of the spark plugs are wet with fuel. I’ve thought the cylinders were being flooded from the beginning and was hoping fuel pressure would fix it. Tonight I am going to pull the rail and watch the injectors spray. Don’t know how to test/diagnose if the plugs are firing in correct sequence but that should be a timing thing and as far as timing goes my car still has the half moon for the cas can only install it 1 way. And my mechanical timing is 100% correct I posted photos above. Confirmed with the balancer on and off. 
×
×
  • Create New...