Jump to content
SAU Community

Recommended Posts

Hi chaps,

It seems whenever I take my car to the local track (Barbagallo), I experience the following:

  • fuel surge when tank is approx <60% full
  • high fuel consumption - roughly 6 laps will consume 1/4 of the tank

Additionally, when at the tuners, they said that the injectors are maxed out; they're not completely sure what the reason is. Initially it was believed to be a lazy pump, however after swapping that out, it seems to still be the same.

My fuel setup (and other possibly pertinent information) is as follows

  • R34 GT-Four (not sure if they run a different style fuel tank, or smaller fuel hosing, given it used to be an N/A car from factory)
  • RB26DETT
  • Approx 515hp on a hub dyno, which is usually reading a bit higher than roller dynos
  • Running E85
  • Deatschwerks 1200cc injectors
  • Walbro 460lph intank fuel pump
  • Standard fuel rail and FPR
  • Unsure of fuel filter, I don't think it's anything fancy, but has been changed a couple of times since switching to E85

Since swapping fuel pumps, not completely sure if the surging is still present, as I kept the fuel topped up each time I went out; however the workshop said the previous pump was secured well, and was low down, so there was no reason for it to surge previously.

I am considering putting in a fuel surge tank, -10 micron filter, new fuel rail and an adjustable FPR to try and fix all the above items, however just wanted to see if someone has any ideas before I embark down this road.

The other strange thing is that I know another car which is exactly the same fuel pump and injectors as me, however is sitting at 100hp more with breathing room on the injectors, and another car which has same injectors (different fuel pump), but is over 700hp

Thanks!

You should have heaps of fuel for that power level. Fuel rail and FPR "should " be up to it. Have you tested the fuel pressure? Maybe you have struck a dud pump. Have you wired the pump for full battery voltage? Have you seen the afr chart? Is it possible that it is a problem with the tune?

Hey guys, thanks for that!

I don't have any fuel pressure gauges on it, that's something the tuner did and said they had maxed out

Pump is wired up for full voltage, the AFRs were previously a bit on the lean end up top, which has now been rectified so that they're "safe", but I don't have a copy of it sorry ...

The tuner is very good, I don't think there's any issue on that front

Sorry for the noob question, but I if I had a fuel pressure gauge on it, and for example the fuel filter is blocked, that would then be able to tell me that the filter is blocked and the injectors are over-working/hitting max duty-cycle, due to the reduced fuel flow (given by the pressure)?

My R34 has had issues with fuel filters before. Changed to an Earls and changed that when it became blocked, but I noticed this by the car running lean under power, which coincidentally was about the same amount of power you have :P

All it took for me was to run one tank of 98 and switching back to E85 to see my filter full of stuff. Pretty much want to change it any time I do an oil change now, I would lose my mind if I didn't have a wideband that will cut the engine if the event of a lean condition as I'm super paranoid about fuel filters now.

those are 1000cc with normal rail pressures, those DW are a 4 or 5 bar base 1200cc rating.

your power is around 390rwkw and is around right for getting close to max. (390-420)

It's interesting how DW and other brands feel the need to rate injectors at higher pressure to make them sound larger than they are.

My 1000's are actually 5000cc at 100 bar rail pressure. ;)

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

    • Yeah well per the video it took 15s for the stock unit to start up....even if I give it a few seconds discount for starting that is at least 12 sec before you get a reverse camera if you are trying to leave a park.  The android unit is way faster, but 2016 for the stock unit is a long time ago in consumer electronics
    • Yea that’s why I said ima test them with multimeter and see the reads.
    • Only at idle. Isn’t a problem when rev it seems.
    • @Haggerty This seems silly to ask, but are you confident in your ability to tune the Haltech?  
    • Next on the to-do list was an oil and filter change. Nothing exciting to add here except the oil filter is in a really stupid place (facing the engine mount/subframe/steering rack). GReddy do a relocation kit which puts it towards the gearbox, I would have preferred towards the front but there's obviously a lot more stuff there. Something I'll have to look at for the next service perhaps. First time using Valvoline oil, although I can't see it being any different to most other brands Nice... The oil filter location... At least the subframe wont rust any time soon I picked up a genuine fuel filter, this is part of the fuel pump assembly inside the fuel tank. Access can be found underneath the rear seat, you'll see this triangular cover Remove the 3x plastic 10mm nuts and lift the cover up, pushing the rubber grommet through The yellow fuel line clips push out in opposite directions, remove these completely. The two moulded fuel lines can now pull upwards to disconnect, along with the wire electrical plug. There's 8x 8mm bolts that secure the black retaining ring. The fuel pump assembly is now ready to lift out. Be mindful of the fuel hose on the side, the hose clamp on mine was catching the hose preventing it from lifting up The fuel pump/filter has an upper and lower section held on by 4 pressure clips. These did take a little bit of force, it sounded like the plastic tabs were going to break but they didn't (don't worry!) The lower section helps mount the fuel pump, there's a circular rubber gasket/grommet/seal thing on the bottom where the sock is. Undo the hose clip on the short fuel hose on the side to disconnect it from the 3 way distribution pipe to be able to lift the upper half away. Don't forget to unplug the fuel pump too! There's a few rubber O rings that will need transferring to the new filter housing, I show these in the video at the bottom of this write up. Reassembly is the reverse Here's a photo of the new filter installed, you'll be able to see where the tabs are more clearing against the yellow OEM plastic Once the assembly is re-installed, I turned the engine over a few times to help build up fuel pressure. I did panic when the car stopped turning over but I could hear the fuel pump making a noise. It eventually started and has been fine since. Found my 'lucky' coin underneath the rear seat too The Youtube video can be seen here: https://www.youtube.com/watch?v=uLJ65pmQt44&t=6s
×
×
  • Create New...