Jump to content
SAU Community

R33 Fuel Pump - Stock Setup

MBS206

By MBS206,
in Engines & Forced Induction

 Share

Recommended Posts

MBS206 Grand Master

MBS206

Posted
Posted

Alrighty guys and girls.

Putting an ECU into my car, and have come across a problem whilst tuning.

At 5000RPM, 10.5PSi, my AFR (On a wideband 02) is going to the maximum richness of 13:1 (WOAH, thats bad!)

Now, car is running stock fuel pump, stock fuel reg, stock injectors.

Fuel pump is wired up using the fuel pump relay pin on the stock wiring loom, but from what I can gather, there is another circuit in there also, that enables the fuel pump to enter a faster running state. Now, from what I can see from wiring diagrams, this is something like pin 106, but the issue is, I would like to know how the stock ECU operates this.

Does it:

a) Provide 12Volts when the higher state is required?

b) Ground out the wire, when the higher state is required?

I know that this can be tested, but I can't get to the car right now, and won't be able to for a little while, and was just wanting some knowledge on how this setup operates.

Also: At the moment, I would prefer to NOT be going to do the fuel pump direct feed mod that is written in the FAQ section. So please, don't mention it.

And don't mention, "get a bigger pump" etc as this isn't the pump, or fuel systems limit.

The stock ECU, at the same boost pressure sees AFRs around 10.5:1 - 11:1 so it seems to be that the whole fuelling side of the car, I'm not quite understanding (Electrically on the fuel pump itself)

Any help on how this system works?

Link to comment
https://www.sau.com.au/forums/topic/176308-r33-fuel-pump-stock-setup/
Share on other sites
MBS206 Grand Master

MBS206

Posted
  • Author
Posted

Okay guys, I've been PM'd the info that I needed, and for those in the future who want this info.

The fuel pump runs at dual stage, just connect the fuel pump relay wire will give you low speed.

From the info I was sent, grounding pin 104 sends the pump into high speed mode, delivering more fuel.

Will let you know on Saturday night how I go.

This can be locked now if the mods want.

Matt

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • brillo
      Leak from Tokico BM50 Brake Master Cylinder

      By brillo · Posted

      Hi, SteveL Thank you very much for your reply, you seem to be the only person on the net who has come up with a definitive answer for which I am grateful. The "Leak" was more by way of wet bubbles when the pedal was depressed hard by a buddy while trying to gey a decent pedal when bleeding the system having fitted the rebuilt BM50 back in the car, which now makes perfect sense. A bit of a shame having just rebuilt my BM50, I did not touch the proportioning valve side of things, the BM50 was leaking from the primary piston seal and fluid was running down the the Brake booster hence the need to rebuild, I had never noticed any fluid leaking from that hole previously it only started when I refitted it to the car. The brake lines in the photo are "Kunifer" which is a Copper/Nickel alloy brake pipe, but are only the ones I use to bench bleed Master cylinders, they are perfectly legal to use on vehicles here in the UK, however the lines on the car are PVF coated steel. Thanks again for clearing this up for me, a purchase of a new BMC appears to be on the cards, I have been looking at various options in case my BM50 was not repairable and have looked at the HFM BM57 which I understand is manufactured in Australia.  
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      PXL_20250828_063541093.TS.mp4
    • Gantai
      R33 GTST Steering Rack (49001-19U05) Rebuild?

      By Gantai · Posted

      Well the install is officially done. Filled with fluid and bled it today, but didn't get a chance to take it on a test drive. I'll throw some final pics of the lines and whatnot but you can definitely install a DMAX rack in an R33 with pretty minor mods. I think the only other thing I had to do that isn't documented here is grind a bit of the larger banjo fitting to get it to clear since the banjos are grouped much tighter on the DMAX rack. Also the dust boots from a R33 do not fit either fyi, so if you end up doing this install for whatever reason you'll need to grab those too. One caveat with buying the S15 dust boots however is that the clamps are too small to fit on the R33 inner tie rod since they're much thicker so keep the old clamps around. The boots also twist a bit when adjusting toe but it's not a big deal. No issues or leaks so far, steering feels good and it looks like there's a bit more lock now than I had before. Getting an alignment on Saturday so I'll see how it feels then but seems like it'll be good to go       
    • PranK
      R35 GT-R production ends after 18 years

      By PranK · Posted

    • SteveL
      Leak from Tokico BM50 Brake Master Cylinder

      By SteveL · Posted

      I don't get in here much anymore but I can help you with this.   The hole is a vent (air relief) for the brake proportioning valve, which is built into the master cylinder.    The bad news is that if brake fluid is leaking from that hole then it's getting past the proportioning valve seals.   The really bad news is that no spare parts are available for the proportioning valve either from Nissan or after market.     It's a bit of a PITA getting the proportioning valve out of the master cylinder body anyway but, fortunately, leaks from that area are rare in my experience. BTW, if those are copper (as such) brake lines you should get rid of them.    Bundy (steel) tube is a far better choice (and legal  in Australia - if that's where you are).
×
×
  • Create New...