perry3188

I'm using a fiesta rst efi inlet manifold and fuel rail for an 1800 zetec turbo. Do I need to replace or adjust the regulator? Only running 1 bar of boost and still unsure what injectors to choose.
Cheers

grant_xr

You need to run whatever fuel pressure the management had been mapped to. What management you using?

Grant

xr2wishy

iTrader: (2)

rst efi fuel regs are adjustable anyhow, but grant is on the money.
fuel pressure is only one part, the others are injectors and mapping.
typically 3BAR on many injectors out there to get a nice spray pattern, but many can take more and will flow more at the expense of service life being shortened.

perry3188

Megasquirt. I've got an uprated in line fuel pump that runs happy at 3 bar and up to 8. Is the frst rising rate? Any idea what pressure it's set to?

studabear

it will be set to around 3 bar, yeah it is a rising rate, I would invest in a fuel pressure gauge for initial set up.

xr2wishy

iTrader: (2)

most fuel regs are rising rate at 1:1 which is what you need. not entirely sure what they are set to as standard, but think 3BAR, just pop the centre cap off the front of the reg (looks like a small circle) and under you will see the allen head for adjustment.
fuel pumps with boost need to be more than happy at 3BAR, they need to be happy at base pressure plus what ever boost e.g. 3 bar to injectors to maintain flow, plus 1 bar of boost will mean the pump will have to pump 4BAR and flow enough. an rst or cossie pump will do 200bhp+ no sweat, 4wd cossie would take 400bhp i've been told.
a gauge is a must, can be bought as cheap as Ł15 for testing purposes.

perry3188

So am I right in saying set it to 3 bar at idle? Or go to 3.5? Pump was advertised as a 250bhp pump.

xr2wishy

iTrader: (2)

nope, do not set it to 3 bar at idle, the vacuum in the inlet will create a low pressure area and actually effectively draw too much fuel through the injector.
you need to set it to 3bar when throttle open fully or engine not running.
to be fair with mappable engine management as long as the injectors aren't stressed then you can map around the pressure if you change it anyhow.

scoooby slayer

iTrader: (4)

it will all depend on the map.
normally its 3 bar base pressure which is vac pipe removed at idle, but if its been mapped with 2.5 bar base pressure then you need to run 2.5 bar.

studabear

Can you set it with the vac pipe disconnected then Sean?

This gauge should help you set it, http://www.ebay.co.uk/itm/Fuel-Press...item2a38cccdce

Then remove it once set.

xr2wishy

iTrader: (2)

you can do it with vac pipe off, having a tired moment lol!
that's the second child one week old making me stop thinking clearly....
as long as there is a 3bar differential of pressure from one side of the injector to the other it will be fine.

perry3188

Can anyone confirm the correct procedure to set the pressure? Gauge before rail? Engine off, pump running, vac disconnected?

scoooby slayer

iTrader: (4)

honestly I don't mean to sound funny but if you don't know you shouldn't really be messing with it.

if its not running you wont need to take the vac pipe off as there will be no vacuum there the pull the regulator into lower than base pressure.

does your pump just run constant bat feed or is it varied voltage ?
a change in fuel pressure can cause an engine to run lean very easily.......

perry3188

The pump will be wired direct 12v on a switched relay. I'm a qualified mechanic, just never adjusted fuel pressure as its not a job people want doing regularly at an MOT station! Just thought someone who had done the job on that specific regulator might be able to share their experience.