Fuel Pump Problem

[azza86]

Hey, i have an R33 Gtst and i just replaced the fuel pump with a Walbro Gss342 and since doing so have had trouble getting anymore than 40 psi at the regulator, its a brand new regulator and i tried two gauges with same results. It seems that the pump is struggling to make pressure does this sound like a faulty pump or something else, any advice would be much appreciated.

[Moodles2]

Skylines have a 6v/12v regulator on the fuel pump, Walbro pumps work ok'ish at 12v, and hate 6v even more (idle/low load). Give it direct alternator voltage and see if it still happens.

[Hanaldo]

As above, needs to be rewired.

[rondofj]

I had same prob, look for threads on how to rewire pump for direct 12v feed.

[azza86]

Thanks guys, checked voltage was only around 11V going to rewire it this afternoon.

[Hanaldo]

I had same prob, look for threads on how to rewire pump for direct 14v feed.

Fixed.

[azza86]

Okay I re-wired the fuel pump this afternoon checked the voltage was 13.8v got good fuel pressure while the engine was cold and screwed the reg back to 44 psi, after going for a short drive and warming the engine up i can't get any more than 40 psi again with the vac hose disconnected even if i screw the regulator right in.

[MrStabby]

Was the 40 psi at idle or at load? Were you able to get a decent AFR at idle/load?

[azza86]

It's definitely fixed now decided to put a direct earth wire to the battery, straight after doing this i noticed the difference and the fact that it pumped up to 100psi so i screwed it right back to 44psi no vac hose and everything seems normal now but makes me wonder might have a crappy earth connection somewhere where does the earth connect to on the body i see the battery is connected to the body buy where does everything else get its earth.

[MrStabby]

I was wondering if there was a problem with how the engine ran, or was it just that the low psi number concerned you.

[Crans]

As part of rewiring the fuel pump the fuel pumps earth should go straight to where the battery earths