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Fuel pressure regulator on fuel rail and new FPR

Posted: Wed Jun 27, 2007 10:28 am
by Speed breeder
Hi everyone

I installed a "7 bar" in tank fuel pump last year in my 200sx during building the car. Suffering from surging, I decided to install a autogauge fuel pressure regulator and replace all fuel hoses.

I left the original fuel pressure regulator on the fuel rail.

The car still seems to be surging.

The pressure before and after the new pressure regulator, which I installed directly after the fuel filter seems to be 3 bar only.

I have connected the fuel pressure regulator gauge before the FPR and an additional electronic pressure sender after the FPR which sends the signal to a gauge inside the car.

Both gauges indicate the same pressure.

My questions: Why would the pressure be so low if I purchased a 7 bar fuel pump?
What is the original fuel pump pressure delivery?

I will replace all the fuel filters this weekend- i have one before the fuel pump and one in the engine bay before the fuel pressure regulator.

The one in the tank is to protect the fuel pump.

The fuel pump is not a Mr Turbo pump but a bosch type which actually says 7 bar on the head, cost R700.

Re: Fuel pressure regulator on fuel rail and new FPR

Posted: Wed Jun 27, 2007 10:33 am
by veecee
Speed breeder wrote:Hi everyone

I installed a "7 bar" in tank fuel pump last year in my 200sx during building the car. Suffering from surging, I decided to install a autogauge fuel pressure regulator and replace all fuel hoses.

I left the original fuel pressure regulator on the fuel rail.

The car still seems to be surging.

The pressure before and after the new pressure regulator, which I installed directly after the fuel filter seems to be 3 bar only.

I have connected the fuel pressure regulator gauge before the FPR and an additional electronic pressure sender after the FPR which sends the signal to a gauge inside the car.

Both gauges indicate the same pressure.

My questions: Why would the pressure be so low if I purchased a 7 bar fuel pump?
What is the original fuel pump pressure delivery?

I will replace all the fuel filters this weekend- i have one before the fuel pump and one in the engine bay before the fuel pressure regulator.

The one in the tank is to protect the fuel pump.

The fuel pump is not a Mr Turbo pump but a bosch type which actually says 7 bar on the head, cost R700.
3 bar pressure after the regulator? interesting.

the stock regulator should limit the pressure to 2.5-3 bar. by adding an adjustable FPR and leaving the original (stock) one there, you kinda negate the use of the aftermarket one?

after the FPR though there, its just a run off back to the tank, and i'm not sure if my logic is correct, but there shouldnt be much pressure on that line at all.

Posted: Wed Jun 27, 2007 10:39 am
by Speed breeder
The second gauge is in the fuel delivery line to the fuel rail.

How do I go about removing the original FPR, as it looks like it forms part of the fuel rail?

How many connections would there be on the the aftermarket FPR?

I have one fuel line going in and one going out of the FPR

The only other connection is to the "retard/advance/throttle body/pop up valve" line. There is no other hole or feed to run a return line to the tank.

I thought the return line would be fed from the fuel rail.

Posted: Wed Jun 27, 2007 10:58 am
by veecee
it does.

the stock FPR is the installed on the fuel rail near the firewall, or piston 4, or whatever else makes sense!

so on a stock system, the fuel rail is pressurised up until that point. once the fuel has passed the pressure regulator, it gets flowed back to the tank.

take pics dude - but post them here. dont keep them to yourself like chemcool would. he's been setting a bad example!

you can get a little adapter from most stores that will bolt onto your fuel rail in place of your stock regulator. its usually an alloy plate, with holes on the sides for the screws, an insert with an o-ring that goes inside rail, and a barbed or flared nipple on the other side that you can attach a fuel hose to!

Posted: Wed Jun 27, 2007 11:14 am
by Speed breeder
Will Post pics...

In the meantime, does the stock FPR just pull out?
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Posted: Wed Jun 27, 2007 11:22 am
by veecee
you will need to remove the screws first, but then yes - it just pulls out!

Posted: Wed Jun 27, 2007 11:35 am
by Speed breeder
Screws, hmmm...I recon me remove them wiff a hammer then huh...
Seems like a pretty dumb question I asked...sorry....
You can see I haven't paid much attention to the old FPR.
Cool Thanks for ur help dude.

Posted: Wed Jun 27, 2007 12:05 pm
by veecee
NP.

Posted: Wed Jun 27, 2007 2:30 pm
by ChemCool
you can get a little adapter from most stores that will bolt onto your fuel rail in place of your stock regulator. its usually an alloy plate, with holes on the sides for the screws, an insert with an o-ring that goes inside rail, and a barbed or flared nipple on the other side that you can attach a fuel hose to!
Tell me about this store please. where are these stores?? :roll:

Posted: Thu Jun 28, 2007 10:14 am
by veecee
ChemCool wrote:
you can get a little adapter from most stores that will bolt onto your fuel rail in place of your stock regulator. its usually an alloy plate, with holes on the sides for the screws, an insert with an o-ring that goes inside rail, and a barbed or flared nipple on the other side that you can attach a fuel hose to!
Tell me about this store please. where are these stores?? :roll:
they should be available at most stores that sell adjustable or aftermarket FPR's.

when i bought my first FPR (which is for sale BTW) i got one of these little attachments for free, because i am a nice guy!!!

that was at volkspares in jet park. but i've seen them at many accessories stores!!!

or get gary to make some - its not difficult. i reckon you could make them with simple garage tools!

Posted: Thu Jun 28, 2007 10:29 am
by Speed breeder
where do I get these simple garage tools...are we talking about the hammer again????


Just kidding...

Posted: Thu Jun 28, 2007 11:04 am
by veecee
hmmm lets see...

i would need a vice, a hacksaw, thread sealant, tap and die set, drill and drillbits, probably a pen and paper, and maybe some spraypaint???

and then the parts - a smallish piece of aluminium, the nipple thingy (check hydraulics stores), a little o ring.

thats it i think!