Jump to content
SAU Community

Recommended Posts

Cubes,

If what you say is correct i will need to look into this quickly.

Just one question though, as you mention i didnt know that the normal trigger for the pump could shut down if the car stalled or such. Good to know really.

  • 5 weeks later...

Hi Guys,

This has been a really interesting read! I was hoping that you guys could clear up a few grey areas that i still have tho.

I am going to be running a bosch 040 or 044 pump inside my tank on my 32 GTR soon as i am upgrading the turbos and what not. My power aim will be around 320awkw and im wondering if this mod is required (as i know the pumps run approx. 230l/hr and 330l/hr respectively at 13.8v)?

Where abouts is the factory voltage control module located in the car?? Is it possible to rewire the pump but still use the factory voltage control module, as to only supply the pump with a lower voltage at idle but still have the 13.8v at higher rpm?? If not, im guessing the Jaycar kit that Sydneykid was talking about will be needed.

Thanks in advance for clearing it up for me.

Tony

I'm not sure about the other PFC's but when I dropped the PFC in to my R32 it constantly supplied the pump with high voltage. No more low voltage on idle with the PFC, In mine and other R32 GTST's I've seen.

I believe it would be possible to rewire the pump to still use the factory voltage control module. From memory I remember seeing something in the manual about the resistor pack to drop the fuel pumps voltage is located in the engine bay.

If its needed in your case.... suck and see... Unless you want to do it just to be safe and possibly save you having to go back for another tune, but chances are with a decent 044 even at the lowever voltage it will be fine. But really.. I don't know as there's a few variables that man influence if its up to the task, fuel pressure, boost and injectors size. Run less fuel pressure and the fuel pump will flow more.

anyone know what kind of current is drawn from the std fuel pump, same with the bosche 044 pumps?

with both of these running from direct power via a switched relay (each) finding its drawing alot of current making the car take longer to start

as in if i prime the system and turn the pumps off, then the car starts easier, then i switch the pumps on.

this is ona 550CA 60amp hour battery

  • 3 weeks later...

sorry about the late reply,

I would look at doing the oposite in your case and run larger cables to the starter motor. One thing that could be an issue is if your cables can not carry the current to run the starter motor, then the cable get hot during your start up, resistance of the cable goes up voltage goes down, then current goes up again! A very nasty circle.

Also a dircet cable from the negitive terminal to the engine block might help as well, if you dont have that already.

hmm its more ECU related than started motor ...

the dash lights go out when cranking then comeback on then the car starts

turning off the pumps just reduce the time the lights turn off for..

strange issue and i havent had time to play around with the currents that are being drawn when doing the above.

Strange,

does the starter motor sound like its struggling to turn the motor over. Do your self a favor if you have a multi meter connect it across the battery terminals and record what your minimum voltage was during the time your starter motor was turning over.

yeah will have a look, but no the starter turns the car over fine, just a momentary drop of power to the PFC

this is reduced further when jump starting the car..

can even get that bad if the battery is low that the car turns over but the lights never come on and it wont start ..

one day i'll find it

Have you had the motor out and rebuilt at any time?

May just be a bad earth.

motor hasn't been out, only ever head off..

have been looking into making my own earth kit for it all.... just a matter of free time which i dont have much of :D

only earth i know to be missing is the one the the turbo manifold.. which has been gone for years

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

    • I saw you mention this earlier and it raised a red flag, but I couldn't believe it was real. Yes, the vacuum signal should vary. It is the one and only load signal from the engine to the ECU, and it MUST vary. It is either not connected or is badly f**ked up in some way.
    • @Haggerty you still haven't answered my question.  Many things you are saying do not make sense for someone who can tune, yet I would not expect someone who cannot tune to be playing with the things in the ECU that you are.  This process would be a lot quicker to figure out if we can remove user error from the equation. 
    • If as it's stalling, the fuel pressure rises, it's saying there's less vacuum in the intake manifold. This is pretty typical of an engine that is slowing down.   While typically is agree it sounds fuel related, it really sounds fuel/air mixture related. Since the whole system has been refurbished, including injectors, pump, etc, it's likely we've altered how well the system is delivering fuel. If someone before you has messed with the IACV because it needed fiddling with as the fuel system was dieing out, we need to readjust it back. Getting things back to factory spec everywhere, is what's going to help the entire system. So if it idles at 400rpm with no IACV, that needs raising. Getting factory air flow back to normal will help us get everything back in spec, and likely help chase down any other issues. Back on IACV, if the base idle (no IACV plugged in) is too far out, it's a lot harder for the ECU to control idle. The IACV duty cycle causes non linear variations in reality. When I've tuned the idle valves in the past, you need to keep it in a relatively narrow window on aftermarket ecus to stop them doing wild dances. It also means if your base idle is too low, the valve needs to open too much, and then the smallest % change ends up being a huge variation.
    • I guess one thing that might be wrong is the manifold pressure.  It is a constant -5.9 and never moves even under 100% throttle and load.  I would expect it to atleast go to 0 correct?  It's doing this with the OEM MAP as well as the ECU vacuum sensor. When trying to tune the base map under load the crosshairs only climb vertically with RPM, but always in the -5.9 column.
    • AHHHH gotchaa, I'll do that once I am home again. I tried doing the harness with the multimeter but it seems the car needed a jump, there was no power when it was in the "ON" position. Not sure if I should use car battery jump starter or if its because the stuff that has been disconnect the car just does send power.
×
×
  • Create New...